Dissertations / Theses on the topic 'Photo–Fenton process'

Durante o processo metalúrgico de usinagem de uma peça ocorre a geração de calor proveniente do atrito ferramenta/peça e cavaco/ferramenta. Para que ocorra uma menor geração de calor possibilitando o manuseio, bem como a minimização na deformação da peça, utilizam-se fluidos, que são soluções lubrificantes à base de óleos, água ou polímeros, podendo ser sintéticos ou não, diminuindo, assim, o coeficiente de atrito reduzindo-se a quantidade de calor gerado no processo. Há uma grande variedade de fluidos de corte disponíveis no mercado que são constituídos por diversos compostos como: aminas, compostos clorados e/ou aromáticos, glicóis, nitrosaminas além da presença de metais provenientes do processo de manufatura, portanto, sem tratamento, não podem ser lançados na rede de esgoto convencional. Atualmente não há um método de tratamento para os fluidos de corte nas indústrias. Nesse contexto, propõe-se um estudo sobre a viabilidade dos tipos de tratamento dos fluidos de corte para uma disposição adequada. Os processos de tratamento propostos neste trabalho compreendem hidrolise ácida e Processo Oxidativo Avançado (POA), mais especificamente, Sistema Fenton, além de propor um tratamento baseado na fotodegradação. A caracterização do fluido antes e após seu tratamento foi realizada por técnicas analíticas e espectrométricas. Os processos oxidativos mostraram-se satisfatórios para o tratamento dos efluentes, reduzindo os níveis de contaminantes aos permitidos pela legislação. O processo foto-Fenton mostrou-se mais eficiente que o processo Fenton na degradação de todos os parâmetros avaliados, incluindo BTEX e HPAs. Os processos de hidrólise ácida não apresentaram resultados satisfatórios, reduzindo apenas os metais aos níveis permitidos para descarte.
During the cutting process, part of the heat generation results from tool-part and chip-tool friction. So that it happens a smaller generation of heat making possible the handling, as well as minimization in the tool deformation, cutting fluids are used, that are the oils base, water or polymeric lubricating solutions, could be synthetic or no, decreasing the attrition coefficient being reduced the amount of heat generated in the process. There is a great variety of cutting fluids that are constituted for several composed as: amines, chlorinated and/or aromatic composed, glycols and nitrosamines besides the presence of metals proceeding of manufacture process, therefore, without a treatment, they cannot be discarded in the conventional sewerage system. At the moment there isn\'t a treatment method for the cut fluids in the industries. In that context, intends a study about the viability types of cutting fluids treatment for appropriate disposition. Treatment processes proposed in this work understand acid hydrolysis and Advanced Oxidative Process (AOP), more specifically, Fenton System, in addition proposing a treatment based on the photodegradation (photo-Fenton process). The characterization of fluid before and after treatment it was accomplished by analytical and spectrometry techniques. Oxidative processes were exposed satisfactory for cutting fluids treatment, reducing the levels of pollutants to the allowed by the legislation. Photo-Fenton process was shown more efficient than Fenton process in the oxidation of BTEX and PAHs. Acid hydrolysis processes didn\'t present satisfactory results, just reducing the metals at the levels allowed for discard.

Cilj  ovog  rada  bio  je  ispitivanje  mogućnosti  primene  modifikovanog  bentonita  kao katalizatora  (ferioksalat  i  Al,  Fe-bentonit  katalizatori)  u  Fenton  i  foto-Fenton  procesu  uklanjanja tekstilne  reaktivne  boje  Reactive  Red  120.  Do  sada  su  objavljene  studije  primene  heterogenog Fenton procesa sa različitim koncentracijama gvožđau katalizatorima i sa kompleksom ferioksalata,međutim, njihovo poređenje u smislu efikasnosti obezbojavanja nije istraženo, što je bio jedan od fokusa  istraživanja  u  ovom  radu.  Osim  toga,  potencijal  sunčeve  energije  predstavlja  16,7%  od ukupno  iskoristivog  potencijala  obnovljivih  izvora  energije  u  Srbiji,  dok  je  prosečno  sunčevo zračenje  u  Srbiji  oko  40%  više  od  evropskog  proseka,  čineći  ga  vrlo  zanimljivim  za  primenu  u ovom tipu tretmana. U cilju što boljeg iskorišćenjasunčevog zračenja i unapređenja fotokatalitičkih performansi  procesa  primenjen  je  parabolični  koncentrišući  reaktor,  koji  je  za  ovu  vrstu  procesa prvi put upotrebljavan. Proučavano je u kojoj meri je solarna fotokataliza značajan segment tehnike za tretman otpadnih voda tokom degradacije perzistentnih jedinjenja, kao što je organska azo boja. Takođe, utvrđen je i potencijal fotolize vodonik-peroksida za obezbojavanjem sintetičkog rastvora date  boje.  Prva  faza  imala  je  za  cilj  sintezu  materijala  primenom  različitih  metoda  pripreme  ikonstrukciju solarnog paraboličnog reaktora, koji će se koristiti u Fenton i foto-Fenton procesima degradacije boje Reactive Red 120. Druga faza je podrazumevala karakterizaciju novosintetisanih materijala i optimizaciju procesa fotokatalize primenom Fenton i foto-Fenton procesa i određivanje postignutih efikasnosti primenjenih procesa. Takođe, vršeno je određivanje stepena mineralizacije i identifikacija degradacionih produkata nakon procesa degradacije tekstilne boje Reactive Red 120, kao  i  primena  foto-Fenton  procesa  na  realnom  efluentu.  Na  osnovu  dobijenih  rezultata  tokom primene Fenton procesa i korišćenjem oba tipa katalizatora u periodima niskog i visokog intenziteta zračenja,  sa  aspekta  postizanja  visoke  efikasnosti  obezbojavanja  i  najmanjeg  izluživanja  gvožđa,može  se  zaključiti  da  je  Fenton  proces  najefikasniji  na  pH  vrednosti  3.  AlFeB  je  pokazao  veću reaktivnost čak i pri manje upotrebljenim dozama od0,05 g u odnosu na CuOFeB (0,2 g), kao i mogućnost  manje  upotrebe  vodonik-peroksida  od  2,5  mM,  za  postizanje  visoke  efikasnosti obezbojavanja i postignut visok stepen mineralizacije. Viši intenzitet sunčevog zračenja omogućava odvijanje reakcije obezbojavanja na višim pH vrednostima primenom oba katalizatora tokom fotoFenton  procesa.  Ovo  je  posebno  izraženo  kod  CuOFeB  tokom  letnjeg  perioda  (pH  7),  čak  i  pri nižim dozama katalizatora. Međutim, najveći udeo u  procesu obezbojavanja pri upotrebi CuOFeB katalizatora ima fotoliza vodonik-peroksida (80%). Suprotno ovim rezultatima, pri istim reakcionim uslovima,  potrebna  je  veća  količina  AlFeB  katalizatora  (0,1  g)  i  niža  pH  vrednost  reakcije,  a efikasnost  procesa  značajno  zavisi  od  početne  koncentracije  H ₂O₂.  Činjenica  da  se  u  pripremi katalizatora koristio bentonit kao prirodan, širokorasprostranjen i jeftin materijal i solarno zračenje kao obnovljiv i alternativni izvor fotona, gore navedene rezultate bi trebalo uzeti u obzir prilikom analize troškova efikasnosti primenjenog procesa. Takođe, primena unapređenih procesa oksidacije se  razmatra  kao  predlog  za  najbolju  dostupnu  tehniku  kada  je  u  pitanju  tretman  otpadne  vode tekstilne industrije, dok se kao dodatne nove tehnike uzimaju u obzir foto-oksidacije i ispitivanje mogućnosti  njihove  primene  u  prečišćavanju  otpadne  vode  u  tercijarnom  tretmanu  na poluindustrijskim sistemima. 
The aim of this study was to investigate the decolorization efficiency of Reactive Red 120  (RR120) synthetic solution using ferrioxalate (CuOFeB) and Al, Fe-bentonite (AlFeB) catalysts in  Fenton  and  photo-Fenton  process.  So  far,  studies  of the  application  of  a  solar-assisted  heterogeneous Fenton process with various Fe loaded catalysts and with ferrioxalate complex have  been published, but according to   the author’s knowledge, their comparison in terms of efficacy of  decolorization  has  not  been  performed,  which  was  one  of  the  focus  of  research  in  this  paper.  In addition, the potential of solar energy represents  16.7% of the total utilized  potential of renewable  energy sources in Serbia, while the average solar radiation in  Serbia is  about 40% higher than the  European average, making it very interesting for  application in this type of treatment. In order to  optimize the use of solar radiation and to improve  the photocatalytic performance of the process, parabolic  concentrating  reactor  was  used  for  the  first  time.  As  a  significant  segment  of  the  wastewater  treatment  technique  during  the  degradation  of  persistent  compounds,  such  as  organic azo dye, solar photocatalysis was studied. Also, the potential of photolysis of hydrogen peroxide for  decolorization of the synthetic dye solution was determined. Aim of the first phase of the study was synthesizing  materials  by  using  different  methods  of  preparation,  and  construction  of  a  solar  parabolic reactor, which will be used in Fenton andphoto-Fenton dye degradation processes. The second phase involved the characterization of newlysynthesized materials and the optimization of the  photocatalytic  process  by  applying  Fenton  and  photo-Fonton  processes,  as  well  as  the  determination  of  achieved efficiency  of  the  appliedprocesses.  Also, the degree  of mineralization and the identification of degradation products after applied processes were determined. Application  of the photo-Fenton process on a real effluent was conducted as well. Based on the obtained results  during  Fenton  process  and  using  both  types  of  catalysts  in  periods  of  low  and  high  intensity  of  radiation, from the aspect of achieving high efficiency of decolorization and smallest iron leaching,  it  can  be  concluded  that  the  Fenton  process  is  most effective  at  pH  3.  AlFeB  showed  greater  reactivity even at less used doses of 0.05  g, compared to CuOFeB (0.2 g), and the possibility of using  less  hydrogen  peroxide  (2.5  mM),  achieving  high  efficiency  and  a  high  degree  of mineralization. Higher intensity of solar radiationallows the reaction to be carried out at higher pH values when using both catalysts during the photo-Fenton process. This is particularly pronounced largest part in the decolorization process using the CuOFeB catalyst has  a photolysis of hydrogen peroxide  (80%).  Contrary  to  these  results,  under  the  same  reaction  conditions,  a  higher  doses  of AlFeB catalyst (0.1 g) is needed at lower pH value  of the reaction, and the process efficiency is significantly dependent on the initial concentration of H ₂O₂. The fact that in the preparation of the catalysts bentonite as a natural, abundant, inexpensive material was used and solar  radiation as a renewable and alternative source of photons, the above results should  be taken into account in the cost-effectiveness  analysis  of  the  applied  process. Also,  the  application  of  advanced  oxidation processes is considered as a proposal  for the best available technique when it comes to the treatment of  wastewater  from  the  textile  industry,  while  as  additional  new  techniques,  photooxidation  is considered as a candidate and the possibility of their application in the treatment of wastewater in tertiary treatment on semi-industrial systems.

The growth of population density in some areas of the planet and the increasing fast advances in technology and energy issues, have resulted in a remarkable increment in the necessity for goods and services, with a subsequent over-exploitation and pollution of the environmental resources. Water, a non-renewable resource, does not escape from the harmful effects of human activity and its increasing pollution levels threaten the normal development of ecosystems and life as well. In the last decades, the occurrence of a new generation of contaminants has been detected in wastewaters, surface and underground waters, and even in drinking water. These substances, called "emerging contaminants" or "emerging pollutants", are not subject to regulation, but their recalcitrant character and their effects as endocrine disruptors suggest that their bio-accumulation will have severe consequences to the environment. These non-biodegradable compunds cannot be removed in conventional wastewater treatment plants, and there is a need for chemical processes to oxidize them at least to bio-degradable or non-toxic species. Advanced oxidation processes (AOPs) have demonstrated to be particularly useful in degrading and eventually mineralizing emerging contaminants, but the complexity of their mechanisms and the high reagent and energy costs involved, make necessary to develop options to improve their performance. This thesis specifically addresses the photo-Fenton process, an advanced oxidation process which has been widely applied and has demonstrated to be efficient in the degradation of recalcitrant organic contaminants. The objective of this thesis is to investigate and to propose operating alternatives to improve the performance of photo-Fenton process. For that aim, it was necessary to fulfill some specific objectives: to perform a detailed study of the variables involved in the process, propose its enhancement throughout a systematic dosage of hydrogen peroxide along the treatment span, simulate the process and to investigate opportunities to optimize the process batch recipe. In the first stage of the investigation, with a clear experimental approach, the variables involved in the process were studied and a novel, flexible and easy-to-implement hydrogen peroxide systematic dosage protocol was proposed, improving the mineralization of three emerging contaminants, reaching almost total mineralization in some of the cases. However, the effectiveness of the protocol is strongly influenced by the crossed effect between the involved parameters. In a subsequent stage, a computational approach, the process involving the proposed dosage protocol is simulated and the performance of the process was predicted at different operational conditions. The opportunities for improving process performance when the parameters concerning the dosage protocol are conveniently adjusted can be addressed. Finally, taking a step forward, a first attempt to investigate the alternatives for process optimization was investigated, demonstrating that operational costs can be reduced without diminishing the quality of the final product. As a final remark, this thesis supposes a step forward in the improvement of advanced oxidation processes and it opens the door to continue developing strategies to model, simulate and optimize these complex processes.

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FACEPE
A presente pesquisa foi motivada pelo desafio em propor um tratamento, em escala laboratorial, para degradar eficientemente os poluentes dos lixiviados provenientes do Aterro Sanitário de Altinho – PE, localizado no Agreste do Estado e em funcionamento e Aterro Controlado da Muribeca – PE, localizado na Região Metropolitana do Recife e fechado desde 2009. Assim, baseado na característica de alta carga orgânica, porém baixa biodegradabilidade dos lixiviados, foi realizado um tratamento físico-químico com aplicação dos processos de coagulação/floculação (CF) e oxidativos avançados do tipo foto-Fenton. Inicialmente, foi feito um tratamento preliminar dos lixiviados por meio de um planejamento fatorial 24, tendo como variáveis independentes: massa do coagulante hidróxido de cálcio, tempo e velocidade de rotação de floculação e tempo de sedimentação. Em seguida, foi aplicado o processo de fotoFenton, sob as mesmas condições, ao sobrenadante proveniente das amostras pré-tratadas por CF e diretamente às amostras brutas. Os resultados mostraram remoções de 89,6% e 83,4% de DQO para a amostra pré-tratada por CF e bruta de Altinho, respectivamente; e remoções de 91,5% e 85,2% de DQO para a amostra pré-tratada por CF e amostra bruta da Muribeca, respectivamente. Comparando esses resultados, decidiu-se pela não realização de um tratamento preliminar visto que o percentual de remoção entre as amostras pré-tratadas e brutas foram relativamente próximos, evitando assim o gasto extra de energia, materiais e tempo. Um planejamento fatorial 33 foi realizado para o tratamento por foto-Fenton para cada amostra de lixiviado dos aterros, variando-se concentração de H2O2, proporção de FeSO4.7H2O:H2O2 e pH, em um tempo reacional de 240 minutos sob radiação solar. Foram obtidos resultados de percentuais de remoções nas faixas de 52,5% a 87% de DQO, 43,5 a 77% de carbono orgânico total (COT) e 39 a 74% de substâncias húmicas (SH) para o lixiviado de Altinho; e 53 a 91% de DQO, 38,5 a 77% de COT e 30 a 64% de SH para o lixiviado da Muribeca. O estudo estatístico de correlação entre pares dessas variáveis mostrou que essas possuem correlação de moderada a altamente forte. Os dados experimentais se ajustaram a um modelo cinético de primeira ordem, alcançando-se 70% de degradação do COT dos dois lixiviados em 30 minutos de reação. Obteve-se a constante cinética (k) igual a 0,0408 min-1 e coeficiente de regressão linear (R2) igual a 0,9862 para o lixiviado de Altinho e k = 0,0373 min-1 e R2 = 0,9727 para Muribeca. A caracterização do lixiviado de Altinho e da Muribeca tratados, em suas condições ótimas, indicou um aumento da biodegradabilidade e uma remoção eficiente da carga orgânica, cor e turbidez. Os lixiviados tratados com diluição 1:10 não apresentaram toxicidade.
This research was motivated by the challenge to propose a treatment in laboratory scale to efficiently degrade pollutants of leachate from the landfill of Altinho - PE, located in the arid zone of the state and in operation, and landfill of Muribeca - PE, located in Metropolitan Region of Recife and closed since 2009. Thus, based on the high organic loading characteristic but low biodegradability of the leachates, a physical-chemical treatment with application of coagulation/flocculation (CF) and advanced oxidative (photo-Fenton) processes were made. Initially, a preliminary treatment of the leachate was done by an experimental design 24 using as independents variables: mass of the calcium hydroxide coagulant, flocculation time, flocculation rotation speed and settling time. Then, the photo-Fenton process was applied, under the same conditions, to the supernatant from the pretreated samples and directly to the raw samples. The results showed 89.6% and 83.4% COD removal for the pretreated sample by CF and raw sample from Altinho, respectively; and 91.5% and 85.2% COD removal for the pretreated sample by CF and raw sample from Muribeca, respectively. Comparing these results, it was decide not to do a pretreatment since the removal percentage between pretreated and raw samples were relatively close, avoiding the extra expense of energy, materials and time. A 33 factorial design was done for the photo-Fenton treatment to each landfills leachate sample, ranging the concentration of H2O2, the proportion of FeSO4.7H2O:H2O2 and pH, at a reaction time of 240 minutes under solar radiation. Percentages of removal results were obtained in the ranges of 52.5% to 87% of COD, 43.5 to 77% of TOC and 39 to 74% of humic substances (HS) to the Altinho’s leachate; and 53 to 91% of COD, 38.5 to 77% of TOC and 30 to 64% of HS to the Muribeca’s leachate. The statistical correlation study between pairs of these variables showed that it has a moderate to highly strong correlation. The experimental data fitted to a first order kinetic model, achieving 70% of TOC degradation for the leachate samples at 30 minutes of reaction. The rate constant (k) was 0.0408 min-1 and the linear regression coefficient (R2) was 0.9862 for Altinho´s leachate and k = 0.0373 min-1 and R2 = 0.9727 for Muribeca’s leachate. The characterization of Altinho and Muribeca treated leachate in its optimal condition, indicated an increase in biodegradability and efficient removal of organic matter, color and turbidity. The both treated leachate samples with dilution 1:10 showed no toxicity.

Nos últimos anos, os processos oxidativos avançados (POAs) têm emergido como métodos potencialmente poderosos para transformar poluentes orgânicos recalcitrantes em substâncias menos tóxicas. O presente trabalho visa estudar a degradação de clorofenóis 2,4-diclorofenol (2,4-DCF) e pentaclorofenol (PCF) em solução aquosa por meio do processo foto-Fenton. Os experimentos foram realizados em um reator fotoquímico, em regime batelada, com recirculação e admissão contínua de peróxido de hidrogênio. Os efeitos das concentrações iniciais de clorofenóis, H2O2 e Fe(II), bem como, da potência da lâmpada de vapor de mercúrio, foram estudados a partir de um planejamento experimental Doehlert em multiplos níveis e analisados segundo a metodologia de superfícies de respostas. A foto-oxidação foi monitorada por medidas da concentração de carbono orgânico total (TOC) e do espectro de absorção da solução ao longo do tempo e, em alguns casos, medidas de toxicidade por meio de bioensaios com Artemia sp. Os resultados dos experimentos realizados com 2,4-DCF evidenciaram degradação gradativa, com remoções de TOC superiores a 99%, após 1 hora de tratamento, além de remoção de toxicidade, mesmo para altas concentrações iniciais do poluente (até ca. 415 mgC L-1). Nos experimentos realizados com PCF observouse decaimento inicial de TOC bastante rápido (15 minutos), o que sugere que a degradação dos clorofenóis torna-se mais rápida com o aumento do número de átomos de cloro ligados ao anel aromático. Foi removida mais da metade do TOC inicial por volta de 30 minutos de reação, obtendo-se remoções de até 90,8% ao final do tratamento. Por outro lado, comparado ao 2,4-DCF, no caso do PCF observou-se redução acentuada da taxa de remoção de TOC após esse tempo, o que pode ser explicado a partir da maior concentração de íons cloreto em solução, da formação de complexo estável desses íons com Fe(III) e de espécies geradas a partir de reações envolvendo esse complexo. No conjunto, os resultados comprovam a viabilidade do processo foto-Fenton para remediação de efluentes aquosos contendo clorofenóis.
In recent years, advanced oxidation processes (AOP) have emerged as potentially powerful methods to transforming organic pollutants into harmless substances. The present work aims to study the degradation of chlorophenols (2,4-dichlorophenol and pentachlorophenol) in aqueous solution by the photo-Fenton process. The experiments were conducted in a batch recycle photochemical reactor with continuous feed of hydrogen peroxide solution. The effects of the initial concentrations of chlorophenols, H2O2, and Fe(II), as well as of the electric power of mercury vapor lamp, were studied by means of a Doehlert multivariate experimental design at multiple levels. Experimental results were analyzed according to the response surface methodology. In order to characterize the degradation of the pollutant, time-measurements of the total organic carbon concentration (TOC) as well as the absorbance spectra of the solution, were carried out. In some cases toxicity bioassays were carried out with Artemia sp. The results obtained from experiments with 2,4-dichlorophenol showed a gradual degradation, with more than 99% of TOC removals after 1 hour of treatment, along with toxicity removal, even for high initial pollutant concentrations (ca. 415 mgC L-1). In the case of pentachlorophenol, a fast initial TOC decrease (around 15 minutes) was observed, suggesting that chlorophenols degradation becomes faster with the increment of chloro atoms number bounded to the aromatic ring. More than a half of the initial TOC was removed around 30 minutes of reaction, rising 90.8% of TOC removal at the end of the treatment. In the other hand, comparing to 2,4-DCF, for PCF a marked reduction of the maximum rate of TOC removal after that time. This can be explained by higher concentrations of chloride ions in the solution, for the formation of stable complexes with Fe(III) ion and resulting species in reaction involving such complexes. As a whole, the results confirm the effectiveness of the photo-Fenton process for the remediation of aqueous solutions containing chlorophenols.

The present study is aimed to analyse the degradation of caffeine in water employing an advanced oxidation process, the photo-Fenton reaction (H2O2/Fe2+/UV). Different concentrations of H2O2 and Fe2+ are used to evaluate the effects of the two reagents on the quality of the water after the reaction and on the kinetics of degradation. The quality of the water is estimated in terms of conductivity, turbidity, colour and aromaticity. These quantities were found to be not dependent on H2O2 concentrations, whereas the Fe2+ concentration affects them in a proportional way. Compared to the limits of European Directives, the resulting conductivity is acceptable. Turbidity and colour exceed the limits, and the observed influence of the catalyst suggests that they are due to iron species, not to reaction products. Finally, the method employed to evaluate the aromaticity, based on absorbance at 254 nm, does not seem to be reliable. The kinetics of degradation are elaborated through measurements of the absorbance at 272 nm as a function of time. The dependence of the reaction rate on H2O2 concentration observed here is small, but even the lowest concentration employed is 16 times larger than that of caffeine. When the H2O2 concentration is kept constant, a nearly direct proportionality results between reaction rates and Fe2+ doses. Further analyses have shown that caffeine can also be degraded only under UV-visible irradiation (no reagents), but the reaction would need a very long time (6% in 45 minutes). With the addition of Fe2+ (without H2O2) the reaction rate was found somewhat higher, while with the addition of only H2O2 (without Fe2+) the photo-degradation rate was found to be 2/3 of that measured using both reagents. Therefore, the Fe2+ catalyst contributes to the degradation, but dissociation of the perossidic O-O bond of H2O2 to give OH• radicals can also be directly caused by UV irradiation.

Substâncias tóxicas como o fenol e outros compostos aromáticos dificultam o tratamento de efluentes via digestores biológicos. Estes compostos tóxicos em altas concentrações são nocivos aos lodos biológicos, podendo inviabilizar por completo o tratamento. Nas últimas décadas, os Processos Oxidativos Avançados (POAs), como os processos Fenton e foto- Fenton, surgiram como alternativa para o tratamento de compostos tóxicos. Os POAs degradam os compostos orgânicos pela geração de compostos oxidantes fortes, como o radical hidroxila, a partir de reagentes como peróxido de hidrogênio. Os processos Fenton e foto-Fenton fazem uso de ferro (II), um catalisador relativamente barato, para catalisar a decomposição do peróxido de hidrogênio, reação denominada como reação de Fenton. Em virtude dos complexos mecanismos presentes nos processos Fenton e foto-Fenton, torna-se necessária uma compreensão da cinética do processo, que envolve reações térmicas e fotoquímicas, por meio de sua modelagem matemática fenomenológica. A modelagem da degradação do fenol via processos Fenton e foto-Fenton proposta por este trabalho começa pela estequiometria dos dois processos, que descreve as reações químicas, térmicas e fotoquímicas existentes. A partir destas, é possível desenvolver o modelo cinético dos processos Fenton e foto-Fenton, no qual se determina a velocidade com que estas reações ocorrem. O passo seguinte é o da modelagem hidráulica (ou de escoamento) dos reatores de processo Fenton e foto-Fenton, sendo que para o segundo processo, o modelo deve levar em conta a propagação da radiação por dentro de reator. Foram realizados 3 experimentos de degradação de fenol via processo Fenton para análise das variações das concentrações de fenol, catecol e hidroquinona. Os dados experimentais são comparados com resultados simulados com intuito do ajuste das constantes cinéticas do modelo. Com as constantes ajustadas, são realizadas comparações entre os processos Fenton e foto-Fenton para análise de suas eficiências. A partir dos modelos matemáticos dos reatores de processos Fenton e foto-Fenton, é desenvolvido um modelo de otimização baseado em superestrutura de redes de reatores para a síntese de uma planta de tratamento de efluentes contaminados com fenol. Objetivou-se a redução dos custos de capital, operação e depreciação desta planta, sujeitos às restrições de projeto e ao modelo da superestrutura, resultando em modelos de programação não-linear inteira mista. Foram geradas soluções ótimas para o tratamento de efluentes contaminados com fenol em redes de um, dois e três reatores de POAs.
Toxic substances such as phenol and other aromatic compounds make the wastewater treatment by biological (aerobic or anaerobic) digestors more difficult. These toxic compounds in high concentrations are harmful for the biological sludge and they may render the treatment impractical. In recent decades, Advanced Oxidative Processes (AOPs) appeared as an alternative for the treatment of toxic compounds. AOPs degrade the organic compounds by generating strong oxidizing compounds, such as the hydroxyl radical, from reactants such as hydrogen peroxide. The Fenton and photo-Fenton processes make use of iron (II), a relatively inexpensive catalyst, to catalyze the hydrogen peroxide decomposition, reaction known as the Fenton reaction. Because of the complex nature of the mechanisms that take place in the Fenton and photo-Fenton processes, the understanding of the process kinetics, which involves thermal and photochemical reactions, becomes necessary through its first-principle mathematical modeling. The modeling of phenol degradation by the Fenton and photo-Fenton processes proposed in this work starts with the stoichiometry of the two processes that enumerates the existing thermal and photochemical reactions. Furthermore, it is possible to develop the Fenton and photo- Fenton kinetic model, which determines the reaction rates. The next step is to model the hydraulic (or flow) behavior of the Fenton and photo-Fenton process reactor, whereas the model for the latter must consider how the radiation propagates inside the reactor. Three experiments of the phenol degradation by the Fenton process were carried out to analyze the concentration variation for phenol, catechol and hydroquinone. The experimental data are compared with simulated results aiming the estimation of the kinetic constants of the model. Using the adjusted constants, the Fenton and photo-Fenton processes were compared to analyze their efficiencies. From the mathematical models of the Fenton and photo-Fenton process reactors, an optimization model based on reactor network superstructure is developed for the synthesis of a phenol contaminated wastewater treatment plant. The objective is to minimize the plant capital, operation and depreciation costs, subject to design constraints and to the superstructure model, thus resulting in mixed integer nonlinear programming models. Optimal solutions were generated for the phenol contaminated wastewater treatment in networks with one, two and three AOP reactors.

O 2,4-diclorofenol (2,4-DCF), poluente modelo usado neste trabalho, é um composto empregado na produção de pesticidas, herbicidas e anti-sépticos, e comumente encontrado em efluentes industriais, sendo considerado um poluente prioritário devido a sua elevada toxicidade e alto poder de persistência no ambiente. Este trabalho objetivou estudar a degradação do 2,4-DCF em reator fotoquímico tubular com coletores parabólicos compostos (CPC) irradiado pelo Sol, operado em batelada com recirculação e admissão contínua de peróxido de hidrogênio à vazão de 11 mL min-1. A oxidação do poluente foi baseada no processo foto-Fenton catalisado por tris(oxalato) ferrato(III) (FeOx), investigando-se os efeitos das seguintes variáveis: concentração inicial de 2,4-DCF ([2,4-DCF] = 21-520 mgCL-1), concentrações de oxidante ([H2O2] = 9,9-130 Mm) e de fotocatalisador ([FeOx] = 0,2-1,8 mM) e área de coleta de fótons (0,196-0,98 m2), estudadas a partir de um planejamento Doehlert em múltiplos níveis. A foto-oxidação foi monitorada por medidas da concentração de carbono orgânico total (TOC) e oxigênio dissolvido (OD), tendo sido identificadas condições com remoção de TOC alcançando 99,8% em 90 minutos de tratamento. Nas análises estatísticas dos resultados, os efeitos da área de coleta de fótons e da concentração de H2O2 concordaram com o comportamento esperado, sugerindo, porém, efeitos sequestradores de radicais hidroxila quando a concentração de H2O2 é alta. A partir dos dados experimentais, obteve-se um modelo de redes neurais, usado para previsão da taxa de remoção de TOC em função do tempo. Através do método HIPR (Holdback Input Randomization Method) e dos pesos associados a cada variável de entrada da rede neural, avaliou-se a importância relativa das variáveis de entrada. De maneira geral, os resultados comprovaram a viabilidade do processo foto-Fenton catalisado por tris(oxalato) ferrato III e irradiado pelo Sol para o tratamento de efluentes aquosos contendo 2,4-diclorofenol.
2,4-dichlorophenol (2,4-DCF), the model pollutant selected in this work, is a compound used in the production of pesticides, herbicides, antiseptics, and commonly found in industrial wastewaters. It is considered a priority pollutant due to its high toxicity and high persistence in the environment. This study investigated the degradation of 2,4-DCF in a tubular photochemical reactor with compound parabolic collectors (CPC) irradiated by the sun, operated in batch with recirculation and continuous feed of hydrogen peroxide at a flow rate of 11 mL min-1. The oxidation of the pollutant was based on the photo-Fenton process catalyzed by tris (oxalate) ferrate (III) (FeOx). The effects of the following variables were investigated: initial concentration of 2,4-DCF ([2,4-DCF] = 21-520 mgCL-1), concentrations of oxidant ([H2O2] = 9,9-130 Mm)); photocatalyst ([FeOx]= 0,2-1,8 mM)), and photon collection surface (0,196-0,98 m2), according to a Doehlert design on multiple levels. The photo-oxidation was monitored by measurements of the concentration of total organic carbon (TOC) and dissolved oxygen (OD). Conditions with TOC removal achieving 99.8% within 90 minutes of treatment were identified. The statistical analysis of the results showed that the effects of photon collection area and the concentration of H2O2 agreed with the expected behavior, but suggests scavenging effects of hydroxyl radicals when the concentration of H2O2 is high. From the experimental data, a model of neural networks was obtained and used to predict the rate of TOC removal with time. Using the method HIPR (Holdback Input Randomization Method) and the weights associated with each input variable to the neural network, the relative importance of input variables was determined. Overall, the results proved the feasibility of photo-Fenton process catalyzed by tris(oxalate) ferrate III and irradiated by the sun, for the treatment of aqueous effluents containing 2,4-dichlorophenol.

Cette étude porte sur l'application de différents procédés d'oxydation avancée, POA (plasma d'air humide, électro-Fenton, photo-Fenton et oxydation anodique avec BDD) pour le traitement des colorants de textile. La particularité de ces procédés tient à la génération dans le milieu d'entités très réactives et très oxydantes, les radicaux hydroxyles *OH qui sont capables d'oxyder n'importe quelle molécule organique jusqu'au stade ultime d'oxydation, c'est-à-dire la minéralisation (transformation en CO2 et H2O). Le plasma d'air humide a été appliqué pour l'oxydation d'un colorant azoïque, l'OD 61. Différents catalyseurs (Fe2+, Fe3+ et TiO2) ont été ajoutés dans leurs conditions optimisées afin d'améliorer les performances du système Glidarc. La combinaison des deux catalyseurs: Fe2+ et TiO2 a permis de décolorer 91% de l'OD 61 au bout de 3 heures et d'atteindre un taux d'abattement du COT de l'ordre de 52% après 10 heures de traitement. La méthodologie de la recherche expérimentale a été appliquée dans ce mémoire afin d'étudier l'influence de: l'intensité du courant, la concentration du colorant et le temps d'électrolyse sur la vitesse de disparition de l'OD 61 et afin de déterminer les conditions optimales de sa minéralisation. Dans les conditions optimales obtenues ([colorant] = 0,53.10-3 mol.L-1, I = 250 mA), le procédé électro-Fenton (EF) permet d'atteindre des taux de minéralisation de l'ordre de 98% dans le cas de l'OD 61 et l'AO 7 et de 88% dans le cas de l'indigo carmine. L'identification des produits intermédiaires au cours de l'électrolyse a permis de proposer un mécanisme de minéralisation de l'AO7. Les constantes cinétiques apparentes et absolues ont été déterminées. La dégradation de l'indigo a été étudiée par oxydation anodique avec BDD (OA-BDD) et par procédé photo-Fenton (PF). Cette étude a montré que l'électrolyse de l'indigo suit une cinétique de pseudo premier ordre et que le taux d'abattement du COT était de l'ordre de 97% et 63% respectivement avec OA-BDD et PF. Une étude comparative pour l'oxydation de l'AO 7 a été menée par trois procédés d'oxydation avancée: PF, OA- BDD et EF-Pt et EF-BDD. Cette étude a montré que le procédé photo-Fenton permet d'atteindre des taux d'abattement supérieurs à 90% après seulement 2 heures de traitement. Toutefois, le PF s'est révélé le plus coûteux suite à l'utilisation de la lumière artificielle UV et l'ajout des réactifs. Par ailleurs, le traitement d'un effluent réel issu de l'industrie de textile par le procédé électro-Fenton avec une anode de platine a permis la minéralisation presque totale du rejet initial (94% du COT initial ont été éliminés).

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The aim of this work was to study the performance of the photo-Fenton process using both the artificial UV and solar sources on the textile effluent treatments. Preliminary photo-Fenton experiments for mineralization and degradation of organic and inorganic pollutants as well as of synthetic dyes were carried out in order to assess the best experimental conditions by photo-Fenton process. As synthetic textile effluent a mixture of six dyes: Solophenyl orange TGL (C25H33ClN6O6S2), Solophenyl blue 71 (C40H23N7Na4O13S4), Solophenyl scarlet BNLE (C44H32N10Na4O16S4), Solophenyl yellow ARL (C48H26N8Na6O18S6), Solophenyl black FR (C44H32N13Na3O11S3) e Navy Blue 98 (C38H24N5Na3O13S3) that contained 50 mg L-1 concentration was prepared and diluted in distillated water. The photo-Fenton experiments by using a set of high-pressure mercury lamps and solar light as artificial and natural UV irradiation sources were performed in laboratory scale. As reactor operational parameters to be optimized by a 33 full factorial experimental design: hydrogen peroxide and divalent iron ion as well as the initial solution pH were chosen as variables, keeping constant a reaction time of 120 min that was enough to warrant the maximum (chemical oxygen demand) COD and color removal. The efficiency of photo-Fenton process applied in the treatment of synthetic and real effluents, was evaluated based on the parameters: values of COD, color, turbidity, total organic carbon (TOC), absorbance at a wavelength of maximum absorption for the dyes and simple aromatic compounds and conjugated reductions, as well as behavior analysis of the evolution the sulfate, nitrate inorganic, organic nitrogen and ammonia concentrations. Second-degree models for the COD and color removal percents were proposed to model the photo-Fenton experiments data in order to reduce the cost of running such a photo-Fenton experiment as well as to obtain optimum values of the reactor operating parameters. Second-degree models were also validated by ANOVA. Predicted yields showed good validation with experimental yields. The values of the optimized reactor operational parameters were 3.0, 6.0 g L-1, and 0.05 g L-1 for initial pH, hydrogen peroxide and divalent iron concentrations, respectively, for both photo-Fenton processes. Based on this optimized experimental conditions, almost 100% removals of physico-chemical parameter such as COD, color, turbidity and COT for real textile effluents. The aromatics compounds were showed more resistant to reaction, persisting for longer. It can be noticed that the degradtion of the organic and inorganic matters were verified by the nitrification process and, the sulfates formation and reduction. The process presented similar efficiencies with both solar and artificial irradiation, thus suggesting the use of solar photo-Fenton, as it proved to be an efficient alternative besides using a source of clean and renewable energy.
O objetivo deste trabalho é avaliar o desempenho do processo foto-Fenton, utilizando energia solar e artificial como fontes de irradiação UV, no tratamento de efluentes têxteis. Foram realizados experimentos preliminares para avaliar a eficiência do processo foto-Fenton na mineralização e degradação dos poluentes orgânicos e inorgânicos, bem como dos corantes sintéticos. Para tanto, foi preparado o efluente têxtil sintético pela mistura de seis corantes: Laranja TGL (C25H33ClN6O6S2), Azul FGLE (C40H23N7Na4O13S4), Escarlate BNLE (C44H32N10Na4O16S4), Amarelo ARLE (C48H26N8Na6O18S6), Preto FR (C44H32N13Na3O11S3) e Marinho BLE (C38H24N5Na3O13S3), em água destilada, com concentração de 50 mg L-1. Os experimentos foram realizados em reatores de escala laboratorial utilizando fontes de irradiação UV natural e artificial. Os parâmetros operacionais dos reatores: pH inicial e a concentração dos reagentes H2O2 e Fe2+, foram otimizados baseados nos valores da demanda química de oxigênio (DQO) e descoloração, a partir de um planejamento fatorial 33 completo com o tempo de irradiação constante em 120 minutos. A eficiência do processo foto-Fenton, aplicado no tratamento dos efluentes sintético e real, foi avaliada baseada nos parâmetros: redução dos valores da DQO, cor, turbidez, carbono orgânico total (COT), absorvância nos comprimentos de onda de máxima absorção relativos aos corantes e aos compostos aromáticos simples e conjugados, além da análise do comportamento da evolução das concentrações de sulfato, nitrato inorgânico, nitrogênio orgânico e amoniacal. Para auxiliar na obtenção das condições ótimas dos parâmetros operacionais do reator e redução dos custos do processo foto-Fenton, as respostas experimentais para a redução da DQO e da cor foram ajustados por um modelo previsto de segunda ordem, o qual apresentou uma boa modelagem dos dados, validado pela ANOVA. Os valores ótimos operacionais do reator, para ambos os processos foto-Fenton no tratamento do efluente real, foram: pH = 3,0, concentração de H2O2 = 6,0 g L-1 e concentração de Fe2+ = 0,05 g L-1. Nestas condições, foram obtidos valores próximos a 100% de redução dos parâmetros físico-químicos DQO, cor, turbidez e COT. Os compostos aromáticos se mostraram mais resistentes a reação, persistindo por mais tempo. A degradação da matéria orgânica e inorgânica foi verificada analisando a evolução do processo de nitrificação e a formação ou redução de sulfatos. Os processos apresentaram eficiências similares tanto com irradiação solar como artificial, desta forma, sugere-se a utilização do processo foto-Fenton solar, pois mostrou ser uma alternativa eficiente além de utilizar uma fonte de energia limpa e renovável.

O lixiviado de aterro sanitário possui constituição complexa e é altamente poluente. Neste contexto, os processos oxidativos avançados se destacam como pré-tratamento, objetivando a remoção ou diminuição da recalcitrância do lixiviado. Neste trabalho foram utilizados os Processos Oxidativos Avançados (POAs) foto-Fenton, ozônio e ozônio combinado com peróxido de hidrogênio. Avaliou-se a influência do pré-tratamento por air-stripping, a variação na produção de ozônio em 80 e 100%, a melhor dose de peróxido de hidrogênio correspondente a 20, 40 e 80% da dose de 6g O3/L empregada nos tratamentos com ozônio, a remoção de matéria orgânica, nitrogênio amoniacal total (NAT), alcalinidade, sólidos dissolvidos totais (SDT) (cloretos), produção de nitrito e nitrato, melhor razão molar [H2O2]/[Fe2+] para o tempo de contato de 80 min no foto-Fenton, uso do número médio de oxidação do carbono (NMOC) e a quantificação do ácido oxálico formado após a aplicação dos POAs. O tratamento por O3/H2O2 (1,2 g H2O2/L e produção de O3 em 80%) obteve a maior remoção de matéria orgânica, 0,14 g massa removida de Carbono Orgânico Total (COT) / massa consumida de O3 e 0,43 g/g para a Demanda Química de Oxigênio (DQO). Quanto ao foto-Fenton, averiguou-se o máximo de 74% remoção de COT e 65% remoção DQO para a razão molar [H2O2]/[Fe2+] igual a 2. Também se notou formação de sólidos sedimentáveis neste processo aplicado ao lixiviado bruto. O pré-tratamento por air-stripping não promoveu incremento na remoção de matéria orgânica. As concentrações de NAT, alcalinidade, SDT (cloretos) se mantiveram elevadas após a aplicação dos POA. Ocorreu formação de nitrato em todos os tratamentos. O uso do NMOC foi adequado e demonstrou ocorrência de oxidação nos processos. A quantificação do ácido oxálico formado após a aplicação dos POAs não foi apropriada nesta pesquisa.
The landfill leachate is a major waste produced by the landfill and its constitution complex and highly polluting motivate research in order to adapt their disposal on the environment. In this context, the advanced oxidation processes stand out as a pretreatment, in order to remove or decrease the recalcitrance of the leachate. In this work we used the photo-Fenton AOPs, ozone and ozone combined with hydrogen peroxide. We evaluated the effect of pretreatment for air-stripping, the variation in the production of ozone 80 and 100%, the best dose of hydrogen peroxide equal to 20, 40 and 80% of the dose of 6g O3/ L used in the treatments with ozone, the removal of organic matter, total ammonia nitrogen, alkalinity, dissolved solids (chlorides), production of nitrite and nitrate, best molar ratio [H2O2]/[Fe2+] to the contact time of 80 min in the photo-Fenton, average number of carbon oxidation use and the measurement of oxalic acid formed after application of the AOPs. The AOP O3/H2O2 (1.2g H2O2/L and O3 production by 80%) had the highest removal of organic matter, 0.14 g of TOC removed mass/ mass consumed O3 and 0.43 g/g for COD. As for the photo-Fenton, it was found a maximum of 74% removal of TOC and 65% for COD removal molar ratio [H2O2]/[Fe2+] equal to 2. It was also noted the formation of settle able solids in the process applied to the raw leachate. Pretreatment by air-stripping did not promote an increase in organic matter removal. Total ammonia nitrogen concentrations, alkalinity, dissolved solids (chlorides) remained high after application of the AOP, indicating possible oxidant demand. For nitrate formation occurred in all treatments, while only the photo-Fenton was no formation of nitrite. The use of average number of carbon oxidation was adequate and showed occurrence of oxidation processes. The quantification of oxalic acid formed after the application of AOPs was not appropriate in this research.

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Pollution is a currently environmental problem of world concern. There are many events such as the discharging of untreated effluents in watercourses that cause the eutrophization of water bodies and bad water quality, as well as an inefficiency or lack of a current environmental law. The main goal of this dissertation was the application of solar and artificial-based photo-Fenton processes and aluminum electrodes-based electrocoagulation method in non coupled mode and in an integrated mode for the tannery effluent treatment. These effluent treatments were carried out in lab-scale reactors. In order to evaluate the performance of the reactor experimental conditions of photo-Fenton reactor, a 33 complete experimental design was performed. The lab scale EC reactor was operated at the 4 A electrical current, 4 cm electrode distance and 3 initial pH optimized values, according to the previous results obtained in another work, while the electrolysis time was varied from 5 to 120 min. For EC and photo-Fenton reactors, their performance was evaluated on the removal values of chemical oxygem demand (COD), color, turbidity, total solids (TS), total fixed solids (TFS), total volatile solids (TVS) and metal concentration. Measurements of physico-chemical parameters for untreated and treated effluent samples were performed applying the Standard Method for water analysis, while metal concentrations were determined by the Synchrotron radiation total Reflexion X-ray Fluorescence technique at Brazilian Light Synchrotron Laboratory. By an optimized photon-Fenton process at 0.5 g Fe2+ L-1, 30 g H2O2 L-1, 3 initial pH, and 120 min reaction time, tannery effluent was treated achieving a high performance in pollutant removal as reported by 98.1, 96.4, 98.8, 71.8, 32.1 and 98.5 percent removal for COD, color, turbidity, TS, TFS, and TVS, respectively. As a primer treatment stage, electrocoagulation technique was not achieved a well successful result based on the physico-chemical parameter values reduction as compared with photo-Fenton process. However, an integrated solar irradiation-based photo-Fenton and Al electrodes-based electrocoagulation with 15 min electrolysis time has achieved recommended values by the Brazilian environmental law for Cr concentration (0.24 mg Cr L-1) and DQO (107 mg O2 L-1). Considering both the costs of electrical energy and material and the generated sludge discharging, one m3 of tannery effluent should cost R$ 56.30 for a treatment system based on an integrated and optimized photo Fenton and electrocoagulation processes. Finally, the integrated solar-based photo Fenton and electrocoagulation method is suggested as an efficient one, instead to apply a unique process.
A poluição ambiental é um dos grandes problemas nos países desenvolvidos e em desenvolvimento. Isto é decorrente de uma série de fatores, como o despejo de efluentes não tratados em corpos hídricos e a ineficiência e/ou a falta de legislação ambiental vigente. O objetivo principal deste trabalho é aplicar os processos foto-Fenton com irradiação solar e/ou artificial, a técnica da eletrofloculação e a integração destes processos no tratamento de efluente de curtume. Ambos os processos de tratamento do foto-Fenton e da eletrofloculação foram conduzidos em reatores a escala laboratorial. Para a técnica da eletrofloculação foi utilizado um par de placas de alumínio como eletrodos no reator de eletrofloculação. Para avaliar as melhores condições de processo do sistema foto-Fenton, foi aplicado um planejamento experimental 33 completo. Para a técnica da eletrofloculação manteve-se constante a intensidade de corrente, pH inicial do efluente bruto e distância entre os eletrodos, variando-se o tempo de eletrólise de 5 à 120 min. A eficiência de ambos os processos foram avaliadas com base na redução de Demanda química de oxigênio (DQO), cor, turbidez, sólidos totais (ST), sólidos totais fixos (STF), sólidos totais voláteis (STV). Para a técnica da eletrofloculação e dos processos integrados também foram avaliados a redução da concentração dos metais pesados. Todas as medidas dos parâmetros físico-químicos foram realizadas aplicando os métodos padrões do Standard Methods for the Examination of Water and Wastewater para amostra não tratada e tratada. As concentrações dos metais pesados foram determinadas usando a técnica de fluorescência de raio X por reflexão total, na linha de Luz (D09-XRF) do Laboratório Nacional de Luz Synchrotron. A maior eficiência na redução dos poluentes verificada no processo foto-Fenton foi de 98,1, 96,4, 98,8, 71,8, 32,1 e 98,5 para valores da DQO, cor, turbidez, ST, STF e STV, respectivamente, nas condições operacionais do reator: concentração de ferro de 0,5 gL-1, concentração de peróxido de hidrogênio de 30 gL-1, pH inicial 3 e tempo reacional de 120 min. No entanto a técnica da eletrofloculação não apresentou boa redução nos valores dos parâmetros físico-químicos. Após a aplicação dos processos integrados do foto-Fenton com irradiação solar e da eletrofloculação em tempo de eletrólise de 15 min, foi alcançado valores mínimos de Cr e DQO no efluente tratado, contendo 0,24 mg Cr L-1 e 107 mg O2 L-1 da DQO. O custo do tratamento do efluente e da disposição final do lodo gerado no processo integrado FFs→EF foi de R$ 56,30 m3 do efluente de curtume tratado. Este processo integrado reduziu as concentrações de cromo, ferro e DQO, a níveis permitidos pelas legislações ambientais. Baseada na redução da matéria orgânica e inorgânica, o método integrado FFs→EF pode ser recomendado como uma substituição eficiente ao método individual.

Philosophiae Doctor - PhD
Emerging micropollutants such as bisphenol-A and 2-nitrophenol present a great threat in drinking water due to their adverse effects. Most conventional technologies in water and wastewater treatment are not designed to eliminate these xenobiotics; instead pollutants are merely transferred from one phase to another. Advanced oxidation technologies (AOTs) however, have been identified as suitable routes for the degradation of these potential damaging substances based on free radical mechanisms and use of less expensive chemicals. Moreover, due to the structural complexity of wastewater and the existence of pollutants as mixtures, no single advanced oxidation technology can convincingly remove all forms of contaminants and then most often than not, a combination of treatment processes is required for an effective purification process. Besides, the problem of adequate degradation of emerging contaminants in the environment, when AOT(s) are used individually, they present inherent problems. For instance, powder TiO₂ photocatalysts obstruct light penetration, thus prevent effective interaction of UV light with the target pollutants, and particulates present problems of post-filtration and recovery of catalyst particles after treatment. Additionally, TiO₂ has a high band gap energy, high electron-hole recombination rate, and is prone to aggregation of the suspended particles. Similarly, the dielectric barrier discharge (DBD) system produces ultra violet light and hydrogen peroxide within the plasma zone which is not fully maximised for the mineralization of persistent organic pollutants. Rapid oxidation and aggregation of nano zero valent iron particles in photo-Fentons process reduce the particles mobility and affect its performance. In the same vein, the jet loop reactor (JLR) system is characterised by low impingement yield, which is responsible for low mineralization rate. In light of this background, this research investigated the degradation of bisphenol-A and 2- nitrophenol in aqueous solution using the following combined advanced oxidation methods: DBD/supported TiO₂ or Ag doped TiO₂ photocatalysts, DBD/photo-Fenton induced process and JLR/UV/H₂O₂. The target was to assess the performance of each single system and then identify the best combined AOTs capable of significantly mineralizing the target compounds. Firstly, two materials were developed namely supported TiO₂ and stabilized nano zero valent Fe. The TiO₂ photocatalyst supported on a stainless steel mesh was synthesised using sol-gel solution of 8 % PAN/DMF/TiCl₄. The influence of calcination temperature and holding time on the formation of nanocrystals was investigated. Afterwards, various amounts of metallic silver were deposited on the (optimum) supported TiO₂ photocatalyst using thermal evaporation. The catalysts were characterized by several analytical methods; HRSEM, HRTEM, EDS, SAED, FTIR, TGA-DSC, UV-vis/diffuse reflectance spectroscopy, XRD, BET, and XPS. The photocatalytic activity of the prepared catalysts was determined using methylene blue as a model pollutant under ultra-violet light irradiation. Secondly, the TiO2 photocatalyst and 2.4 % Ag doped TiO₂ nanocomposites obtained as optimums (in section 1) were combined with the DBD to decompose BPA or 2-NP in aqueous solution. Moreover, the photo-Fenton process was applied for degradation of the model pollutants, and different dosages of stabilized nZVI (in the range of 0.02 -1.00 g) were added to the DBD system to induce the photo-Fenton process and improve BPA or 2-NP degradation efficiency. Finally, a jet loop reactor (JLR) presenting advanced mixing by the “impinging effect” was explored to decompose BPA or 2-NP in aqueous solution as a function of inlet applied pressure, solution pH, and initial concentration of BPA or 2-NP. Subsequently, different concentrations of hydrogen peroxide (H₂O₂) were added to the JLR to enhance the mineralization process. Furthermore, a combination of JLR with in-line UV light and H₂O₂ were further utilised to decompose BPA or 2-NP in aqueous solution. The residual concentration of the model compounds and intermediates were analysed using high performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LCMS). The concentration of the ozone, hydrogen peroxide and hydroxyl radicals generated by the DBD in the presence or absence of a catalyst was monitored using Ultraviolet-visible spectroscopy and Photoluminescence spectroscopy. The results revealed that the optimal thermal conditions to obtain well supported uniformly grown, highly active crystalline TiO₂ catalysts with high specific surface area was 350 ºC at a 3 h holding time in N2 atmosphere with a flow rate of 20 mL/min. Pyrolysis temperature and holding time played an important role on the crystalline nature and photocatalytic activity of the catalyst. Moreover, 2.4 % Ag doped TiO₂ nanocomposites exhibited higher photocatalytic activity for methylene blue degradation than the undoped supported TiO₂ nanocrystals. The results indicated that combining DBD with 2.4 % Ag doped TiO₂ nanocomposites achieved 89 % and 81 % removal efficiency for BPA or 2-NP compared to 67.22 % or 56.8 % obtain when using the DBD system alone. The 2.4 % Ag doped TiO₂ nanocomposites demonstrated excellent activity and offered photochemical stability after four repeated applications.In the case of the photo-Fenton induced process, nano zero valent iron particles (nZVI) stabilized with polyethylene glycol were synthesised using a modified borohydride reduction method. The HRSEM, BET, XRD, and XPS analysis confirmed the formation of filamentous, high surface area iron nanoparticles in the zero valent state. Unlike combined DBD/Ag doped TiO2 nanocomposites, 100 % or complete removal of BPA or 2-NP in aqueous solution was achieved with DBD/nZVI system within 30 minutes compared to 67.9 % (BPA) or 56.8 % (2-NP) with DBD alone after 80 minutes. The removal efficiency was attributable to the production of an increased concentration of OH radicals as well as existence of a synergetic effect in the combined DBD/nZVI system. Five new transformation products namely: 4-nitrophenol (C₆H₅NO₃), 4-nitrosophenolate (C₆H₄NO₂), 4-(prop-1-en-2-yl) cyclohexa-3,5-diene-1,2-dione, (C₉H₈O₂), 4-(2- hydroxylpropan-2-yl)cyclohexane-3,5-diene-1,2-dione (C₉H₁₀O₃), and 1,2-dimethyl-4-(2- nitropropan-2-yl)benzene (C₉H₁₀NO₄) were identified during the degradation of BPA. While, three aromatic intermediate compounds such as 2-nitro-1,3,5-benzenetriolate (C₆H₂NO₅), 2- nitro-1,4-benzoquinone (C₆H₃NO₄), and 2,5-dihydroxyl-1,4-benzoquinone (C₆H₄O₄) respectively were identified during the degradation of 2-NP for the first time in the DBD with JT14 or JT17 using LC-MS. These intermediate compounds have never been reported in the literature, thereby expanding the number of BPA or 2-NP intermediates in the data base in the DBD/JT14 or DBD/nZVI system. BPA degradation proceeded via ozonation, hydroxylation, dimerization, and decarboxylation and nitration step, while 2-NP proceeded via hydroxylation, nitration and denitration respectively. Furthermore, maximum removal efficiency of BPA or 2-NP in aqueous solution using JLR alone under the optimum solution pH (3), inlet pressure (4 bar), flow rate (0.0007 m3/s) was 14.0 % and 13.2 % respectively after 80 minutes. A removal efficiency of 34.9 % was recorded for BPA while 33.2 % was achieved for 2-NP using combined JLR/UV under the same conditions as JLR alone. For the combined JLR/H₂O₂ under optimum conditions of inlet pressure (4 bar), solution pH (3) and peroxide dosage (0.34 g/L), a 51.3 % and 50.1 % removal efficiency was achieved for BPA and 2-NP respectively under same conditions relative to JLR alone. Combination of JLR/UV/H₂O₂ achieved 77.7 % (BPA) or 76.6 % (2- NP) removal efficiency under the same conditions. The combined JLR/UV/H₂O₂ process was found to be most effective combination under the optimized operating parameters due to existence of a synergetic index value of 6.42 or 6.84. This implies that JLR should be coupled with UV and H₂O₂ to achieve greater mineralization efficiency instead of using the system individually. The obtained experimental data of these combined treatment processes fitted the pseudo-first order kinetic models. The combination of the JLR/UV/H₂O₂ was found to be energy efficient and could effectively degrade BPA or 2-NP in aqueous solution to a greater extent than the JLR, JLR/UV or JLR/H₂O₂ system. However, the total organic carbon (TOC) reduction value by all combined DBD and JLR system recorded was not completely achieved due to the formation of recalcitrant intermediate compounds under the applied conditions. In conclusion, this study is reporting for the first time a combination of supported 2.4 % Ag doped TiO₂ nanocomposites with dielectric barrier discharge system for BPA/2-NP degradation in aqueous solution; a combination jet loop reactor based on impingement with in-line UV lamp and H2O2 for successfully decomposing BPA or 2-NP in aqueous solution; as well as a combination of dielectric barrier discharge system and stabilised nano zero valent iron particles, which induced a photo-Fenton process for highly effective removal of BPA or 2-NP in aqueous solution. This study conclusively supports the hypothesis that combined advanced oxidation technologies offer a sustainable and highly efficient means of achieving partial or complete removal of BPA or 2-NP in aqueous solutions. Considering all the combinations of AOTs investigated in this study, the novel DBD/photo-Fenton-induced process under optimised operating parameters was found to be the most efficient in the elimination of BPA or 2-NP in aqueous solutions. The combination of DBD with photo- Fenton like process offers a promising advanced waste water purification technology in the immediate future. Based on these findings, it is recommended that DBD should be redesigned to prevent loss of ozone and JLR system reconfigured to increase impingement and cavitational yield in order to have an effective combination treatment strategy for waste water purification especially in large scale waste water management.
National Research Foundation (NRF) and Water Research Commission, South Africa

Espécies nitrogenadas vem sendo adicionadas ao meio ambiente de forma intensa desde o desenvolvimento do processo Haber-Bosch para transformação de N2 em NH3, alterando significativamente o ciclo biogeoquímico do nitrogênio no ambiente. Uma vez na atmosfera, o nitrogênio reativo é depositado de volta à superfície da Terra por processos de deposição úmida e seca. A importância de levar em conta as formas orgânicas de nitrogênio para estimar a deposição de nitrogênio atmosférico pela chuva (úmida) já é conhecida, no entanto, ainda há poucos trabalhos que avaliam essa fração devido às dificuldades e incertezas impostas pelos métodos analíticos disponíveis. Este trabalho traz o desenvolvimento de um novo método, simples e de baixo custo, para a determinação de nitrogênio orgânico (N-org) em água de chuva utilizando o processo foto-Fenton e um foto-reator construído de forma artesanal. Por meio da adição de solução de Fenton (50 µmol L-1 Fe2+ e 2 mmol L-1 H2O2) e 90 min de radiação UV (85 °C) foi possível obter em média 106 ± 8% de recuperação de nitrogênio para soluções contendo 50 µmol N L-1 das moléculas modelos: ureia, serina, glicina e histidina. No caso da arginina, 90 min de radiação foi suficiente para degradar soluções contendo 10 µmol N L-1. O reator comercial se mostrou mais eficiente na degradação dos compostos testados (30 min), no entanto, com um tempo de 75 min, o reator artesanal atingiu os mesmos resultados. Com o uso de 0,2 g L-1 TiO2 e 120 min de radiação UV, também foi possível obter resultados satisfatórios. Porém, esse método possuiu valores de branco elevados, havendo necessidade de filtrar as amostras irradiadas antes da análise, adicionando tempo e custo ao procedimento analítico. O método desenvolvido utilizando foto-Fenton foi aplicado para a determinação de N-org em amostras de água de chuva coletadas na cidade de Ribeirão Preto (SP) de 2013 a 2017. A concentração de N-org variou de 3,5 a 195 µmol N L-1 com concentração média ponderada pelo volume (MPV) de 17,7 ± 1,0 µmol N L-1 (n=236). Essa média foi maior que aquelas obtidas em água de chuva de várias partes do mundo, podendo ser atribuída a elevada queima de biomassa na região de estudo. As concentrações de aminoácidos livres dissolvidos (AA) representaram em média 15 ± 12% (n=144) em relação à fração orgânica de nitrogênio na chuva, enquanto as concentrações de ureia foram próximas ou inferiores ao limite de quantificação do método (0,5 µmol N L-1). Considerando toda série temporal iniciada no mesmo sítio amostral desde 2005, as concentrações MPV calculadas para os íons NH4+ foi de 22,2 ± 1,1 µmol L-1 (n=460), NO3- de 13,3 ± 0,6 µmol L-1 (n=466), sendo que a concentração de NO2- foi irrelevante. Foram obtidas concentrações significativamente mais elevadas (teste-t, P=0,05) de NH4+, NO3-, N-org e AA no período de safra da cana (seco) com relação à entressafra (chuvoso), para todos os anos avaliados. Apesar da colheita manual da cana ter sido drasticamente reduzida, o fato de manter a mesma tendência sazonal desde 2005, demonstra que a prática da queima de biomassa ainda é intensa na região. O uso de fogo para manejo na área rural ainda é comum, além de haver grandes áreas queimadas de forma acidental. A deposição úmida de nitrogênio (N-org + NH4+ + NO3-) para Ribeirão Preto foi de 10,5 kg (N) ha-1 ano-1, sendo que a fração orgânica representou 33% dessa deposição, demonstrando a importância de se determinar N-org para melhor estimar os fluxos atmosféricos de deposição. A massa estimada de nitrogênio depositada pela chuva é cerca de 16% do nitrogênio aplicado por meio de fertilizantes em culturas de cana. Somando as deposições de nitrogênio pelo material particulado, pela fase gasosa, e úmida, esta última representa 71% do fluxo atmosférico de nitrogênio. Nesse contexto, a fração orgânica corresponde a 24% da deposição total, sendo que este valor ainda pode estar sendo subestimado, pois as concentrações de N-org no material particulado não foram determinadas. A simplicidade e exatidão do método aqui proposto pode facilitar a aquisição de dados de N-org na chuva de outras partes do mundo, melhorando assim o conhecimento sobre o ciclo biogeoquímico global do nitrogênio.
Nitrogen species have been intensively added to the environment since the development of Haber-Bosch process for N2 transformation to NH3, significantly altering the biogeochemical cycle of nitrogen. Once in the atmosphere, reactive nitrogen is deposited back to the Earth\'s surface by wet and dry deposition processes. The importance of taking into account the organic forms of nitrogen to estimate atmospheric nitrogen deposition by rain is already known. However, few studies evaluated this fraction due to the difficulties and uncertainties imposed by the available analytical methods. This work presents the development of a new, simple and low-cost method for the determination of organic nitrogen (N-org) in rainwater using photo-Fenton process and a homemade photo-reactor. By adding Fenton solution (50 mol L-1 Fe2+ and 2 mmol L-1 H2O2) and keeping the reaction under UV radiation for 90 min (85 °C), it was possible to obtain an average of 106 ± 8% nitrogen recovery for solutions containing 50 mol N L-1 of the model molecules: urea, serine, glycine and histidine. In the case of arginine, 90 min of radiation was sufficient to degrade solutions containing 10 mol N L-1. A commercial reactor showed to be more efficient in degradation of the tested compounds (30 min). However, with a time of 75 min, the homemade reactor achieved the same results. With 0.2 g L-1 TiO2 and 120 min of UV radiation, it was also possible to obtain satisfactory results. Nevertheless, this method had high blank values, and filtration of irradiated samples before the analysis was necessary, which increased time and cost to the analytical procedure. The developed method using photo-Fenton was applied to determine N-org in rainwater samples collected in Ribeirão Preto city (SP) from 2013 to 2017. N-org concentrations ranged from 3.5 to 195 mol N L-1 with a volume-weighted mean concentration (VWM) of 17.7 ± 1.0 mol N L-1 (n = 236). This value was higher than those reported for rainwater from different parts of the world, and this fact can be attributed to the high biomass burning in the study region. Dissolved free amino acids (AA) mean concentrations represented 15 ± 12% (n = 144) of the organic nitrogen fraction in rain, while urea concentrations were close to or below the limit of quantification of the method (0.5 mol N L-1). Considering all temporal series, initiated in 2005 at the same sampling site, the VWM concentration calculated for NH4+ ions was 22.2 ± 1.1 mol L-1 (n = 460) and for NO3- was 13.3 ± 0.6 mol L-1 (n = 466), while NO2- mean concentration was irrelevant. Significantly higher concentrations (t-test, P = 0.05) of NH4+, NO3-, N-org and AA were obtained during the harvest period (dry season) in relation to the non-harvest one (rainy season), for all evaluated years. Although manual harvesting was drastically reduced, the fact that the same seasonal trend has been maintained since 2005 demonstrates that the practice of biomass burning is still intense in the region. In rural area, using fire for land management is still common, in addition to large areas burned by unintentional fires. Nitrogen deposition (N-org + NH4+ + NO3-) in Ribeirão Preto was 10.5 kg (N) ha-1 year-1, and the organic fraction represented 33% of this deposition, demonstrating the importance of determining N-org to better estimate the atmospheric deposition fluxes. The estimated mass of nitrogen deposited by rain represents approximately 16% of the nitrogen introduced by fertilizers in sugarcane crops. Summing up the nitrogen deposition by particulate matter, by gas phase, and by rain, the latter represents 71% of the atmospheric nitrogen flux. In this context, the organic fraction corresponds to 24% of the total deposition, and this value may still be underestimated, since N-org concentrations in particulate matter were not determined. The simplicity and accuracy of the method proposed here may facilitate acquisition of N-org data in rainwater from other parts of the world, thus improving the knowledge on the global biogeochemical cycle of nitrogen.

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Com o aumento da população nas últimas décadas, consequentemente aumenta o número de indústrias para suprir as necessidades básicas da população. Dentre essas empresas, a indústria que ganha destaque na região do Paraná é o setor têxtil, onde ocupa o 2º maior pólo confeccionista do Brasil. O grande problema desse setor é que durante o beneficiamento dos tecidos 10-15% dos corantes são lixiviados ao meio ambiente, acarretando sérios danos ao próprio meio ambiente. Desta forma, buscam-se métodos mais eficientes para degradação desta matéria orgânica poluidora, dentre os métodos alternativos que têm sido estudados o Processo Avançado Oxidativo (PAO) é baseado na geração do radical hidroxila (HO•), que é um forte agente oxidante levando a oxidação da matéria orgânica. Esse processo ainda pode ser dividido em vários tipos, como processos com e sem radiação, homogêneos e heterogêneos. Assim o objetivo deste trabalho foi estudar a degradação de um efluente têxtil real utilizando o processo “tipo-Fenton”, onde utiliza-se os filtros de cigarros como material suporte para a imobilização de íons férricos. Para monitorar a degradação foi utilizado técnicas analíticas como Carbono Orgânico Total (COT), Demanda Química de Oxigênio (DQO),Turbidez, Cor, detecção de Ferro Total, e a detecção de peróxido de hidrogênio. Os resultados mostraram que no reator contínuo o COT foi reduzido em 78,62%, a DQO em 64%, a turbidez 65,5%, enquanto que a cor 42% em 90 minutos de reação. A lixiviação de ferro total foi de 0, 072 mg L-1 e o peróxido residual foi 29 mg L-1. Isso mostra a eficiência desse método para tratamento de efluentes têxteis.
With the increase of the population in the last decades, consequently the number of industries increases to satisfy the basic necessities of the population. Among these companies, the industry that stands out in the region of Paraná is the textile sector, where it occupies the second largest confectionary pole in Brazil. The biggest problem of this sector is that during the processing of the tissues 10-15% of the dyes are leached to the environment, causing serious damages to the own environment. The Oxidative Advanced Process (PAO) is based on the generation of the hydroxyl radical (HO•), which is a strong oxidizing agent leading to the oxidation of organic problem. This process can still be divided into several types, such as homogeneous and heterogeneous processes with and without radiation. Thus the objective of this work was to study the degradation of a real textile effluent using the "Fenton-like" process, where the cigarette filters are used as support material for the immobilization of ferric ions. To monitor the degradation, analytical techniques such as Total Organic Carbon (TOC), Chemical Oxygen Demand (COD), Turbidity, Color, Total Iron Detection and the detection of hydrogen peroxide.The results showed that in the continuous reactor the TOC was reduced by 78.62%, the COD by 64%, the turbidity 65.5%, while the color 42% by 90 minutes of reaction. Total iron leaching was 0.072 mg L-1 and the residual peroxide was 29 mg L-1. This shows us the efficiency of this method for treatment of textile effluents.

Neste trabalho, utilizou-se um Processo Oxidativo Avançado (POA) para a degradação de uma solução aquosa contendo uma mistura de metilparabeno e propilparabeno (50 μg L-1 cada). O processo estudado foi o foto-Fenton solar, em um reator do tipo CPC operado no modo batelada com reciclo total. As condições operacionais foram otimizadas por meio da Metodologia de Superfície de Resposta (MSR), sendo elas: 771,6 μg H2O2 L-1, 65,3 μg Fe3+ L-1 e vazão 0,9 L min-1. O pH foi fixado em 2,5. A determinação das concentrações dos analitos foi realizada por Cromatografia Líquida de Alta Eficiência acoplada a um Detector de Arranjo de Diodos (CLAE-DAD), tendo sido monitorado o comprimento de onda 258 nm. Utilizou-se como técnica extratora e de pré-concentração a Microextração Líquido-Líquido Dispersiva (MELLD), sendo o n-octanol o solvente extrator e a acetona o solvente dispersivo. Avaliou-se a cinética de degradação do processo otimizado (em triplicata), obtendo-se uma degradação > 99% em 50 min. As constantes de taxa (em função da dose de energia, unidades m² kW-1) foram 1,2 ± 0,034 (R² = 0,987) e 1,1 ± 0,042 (R² = 0,979) para o metilparabeno e o propilparabeno, respectivamente. O efluente do reator mostrou-se biologicamente inativo, tendo sido testadas sua ecotoxicidade (Lactuca sativa) e sua atividade antimicrobiana (Escherichia coli).
In this work, an Advanced Oxidation Process (AOP) was used for the degradation of aqueous methylparaben and propylparaben (50 μg L-1 each). The studied process was the solar photo-Fenton reaction, using a CPC-type reactor, which was operated in batch mode with total recycle. The experimental conditions were optimized using the Response Surface Methodology (RSM) and the obtained results were: 771.6 μg H2O2 L-1, 65.3 μg Fe3+ L-1, and flow rate 0,9 L min-1. The solution pH was set at 2.5. The analytes concentration were determined by High Efficiency Liquid Chromatography coupled to a Diode-Array Detector (HPLC-DAD), monitoring the 258 nm wavelength. The Dispersive Liquid-Liquid Extraction was used as a pre-concentration and extraction technique before injection, whereas n-octanol was the extraction solvent and acetone was the dispersive one. The optimized degradation process kinetics was assessed (triplicate) and more than 99% degradation was obtained after 50 min. The rate constants (normalized by the energy dose, m2 kW-1 units) were 1.2 ± 0.034 (Rsup>2 = 0.987) and 1.1 ± 0.042 (R2 = 0.979) for methylparaben and propylparaben, respectively. The reactor effluent was biologically inactive, regarding its ecotoxicity (Lactuca sativa) and antimicrobial activity (Escherichia coli).

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Este trabalho tem como objetivo avaliar a atividade catalítica de um rejeito de mineração de ferro para a degradação de micropoluentes presentes no meio aquático em processo foto-Fenton heterogêneo. Como poluentes alvos, foram estudados os fármacos: sulfatiazol (STZ) e sulfametazina (SMZ), fármacos de uso estendido no tratamento humano e veterinário. Esses fármacos têm sido detectados em concentrações de ng L-1 a μg L-1 em águas superficiais, subterrâneas, águas de abastecimento, além de Estações de Tratamento de Esgoto (ETE) onde por processos convencionais não conseguem ser eliminados devido à baixa biodegradabilidade ambiental. Foi realizado um planejamento fatorial 24 para determinar os efeitos dos parâmetros reacionais ̶ pH, concentração de peróxido de hidrogênio, dose de rejeito e tamanho de partícula ̶ sendo a variável resposta a porcentagem de degradação do fármaco quantificado por Cromatografia Liquida de Alta Eficiência (HPLC-DAD) com Limites de Detecção (LD) e de Quantificação (LQ) de 6 μg L-1 e 20 μg L-1, respectivamente. O rejeito de minério foi caracterizado por Difração de Raios- X (DRX), Microscopia Eletrônica de Varredura de Alta Resolução (MEV-FEG), Espectroscopia de fotoelétrons excitados por raios- X (XPS) e Área Superficial Específica (BET). O rejeito foi caracterizado separando-se em duas faixas de tamanho de partícula <180 e ≥180 μm, além do rejeito bruto (sem separar). O resíduo apresentou entre seus principais minerais Fe2O3, SiO2, P2O5, CeO2, TiO2, ZnO, MgO além de outros traços, sendo que não apresenta diferenças significativas na composição nas duas faixas. A condição ótima para a degradação foi em pH 2,5 com 1 mmol L-1 de peróxido de hidrogênio, dose de rejeito de 0,3 g L-1 e usando-se o rejeito bruto como catalisador. Os experimentos de degradação tanto no escuro, quanto irradiado, mostraram boas porcentagens de degradação para os dois fármacos estudados, com porcentagens acima do 50% no escuro e acima de 80% sob irradiação, com cinéticas de pseudo primeira ordem seguindo o modelo cinético de Langmuir- Hinshelwood (L-H) com (r = 0,9861 a 0,9964) com constantes Kaparente de 0,0869 ± 0,0084 e 0,0718 ± 0,0035 para o STZ e SMZ respectivamente. Foi possível também a degradação simultânea de ambos os fármacos nas melhores condições experimentais. Considerando-se que não foi observada remoção por adsorção nem fotólise direita dos fármacos é possível afirmar que o rejeito de minério de ferro atua como catalisador eficiente em processos Fenton uma vez que altas porcentagens de degradação foram obtidas e pode ser um material promissor para esta aplicação, possibilitando agregar valor ao resíduo e diminuir o custo operacional do processo de tratamento.
This work aims to evaluate the catalytic activity of a residue from iron mining on the degradation of micropolluants present in the aquatic environment, by using the heterogeneous photo-Fenton process. The target pollutants studied was: sulfathiazole (STZ) and sulfamethazine (SMZ), drugs that are used in human and animal treatments, which has been detected in concentrations of ng.L-1 and ug.L-1 in superficial and underground water, human water supply and sewage treatment station where by conventional processes can’t be eliminated due to the low environmental biodegradability. A factorial design was performed 24 to determine the effects of the reaction parameters (pH, hydrogen peroxide concentration, residue dose and particle size). The response variable was the percentage of degradation of the drug, quantified by High Performance Liquid Chromatography (HPLC- DAD) with Detection Limits (DL) and Quantification (QL) of 6 μg L-1 and 20 μg L-1, respectively. Iron mining was characterized by X-ray diffraction (XRD), high resolution scanning electron microscopy (SEM), X-ray photoelectron Spectroscopy (XPS) and surface-specific spectroscopy (BET) spectroscopy. The reject was characterized by separating into two particles size < 180 and ≥ 180 μm in addition to the crude (unseparated) reject. The residue presented among its main minerals Fe2O3, SiO2, P2O5, CeO2, TiO2, ZnO, MgO in addition to other traces, and it does not present significant differences in the composition in the two different particle fractions. The optimum degradation condition was at pH 2.5 with 1 mmol L-1 of hydrogen peroxide, waste dose of 0.3 g L-1 and using the crude waste as catalyst. Both the dark and irradiated degradation experiments showed good percentages of degradation for the two drugs studied, with percentages above 50% in the dark and above 80% under irradiation, with pseudo first order kinetics following the Langmuir-Hinshelwood (L-H) kinetic model with (r = 0.9861 to 0.9964) with Kapp constants of 0.0869 ± 0.0084 and 0.0718 ± 0.0035 for STZ and SMZ respectively. It was also possible the simultaneous degradation of both drugs under the best experimental conditions. Considering that adsorption removal and direct photolysis of the drugs were not observed, it is possible to state that the iron ore acts as an efficient catalyst in Fenton processes since high percentages of degradation have been obtained, it can be a promising material for this application. Making it possible to add value to the waste and reduce the operational cost of the treatment process.

O objetivo desta pesquisa foi estudar a degradação,pelo processo foto-Fenton, de um poluente-modelo (um antibiótico da classe dos nitrufuranos:a nitrofurantoína), utilizando-seLEDs-UV no lugar das lâmpadas tradicionalmente utilizadas, ou seja, das lâmpadas fluorescentes negras.Foram comparadas duas câmaras de irradiação, cada uma com um tipo de fonte, em termos de: porcentagem de remoção, ecotoxicidade (Lactuca sativa), atividade antimicrobiana (Escherichia coli), custos de capital (equipamentos), de operação (consumo energético) e das fontes luminosas, além do espaço ocupado. Os experimentos de degradação foramrealizados e otimizados via planejamento experimental, utilizando-se a Metodologia de Superfície de Resposta, obtendo-se as concentrações ótimas denitrofurantoína, de íons férricoe de peróxido de nitrogênio para cada caso.As câmaras estudadas apresentaram desempenhos semelhantes na remoção de nitrofurantoína (mais de 95% em 15 min), além de não ter havido a geração de produtos ecotóxicos (Lactuca sativa) e de ter sido alcançada a inativação biológica (Escherichia coli) do fármaco.A câmara de irradiação com LEDs é compacta, custa duas vezes menos que a outra e é quatro vezes mais eficiente em termos de consumo elétrico. A única desvantagem encontrada foi o custo dos LEDs-UV. Levando-se em conta o número de LEDs e de lâmpadas fluorescentes negras nas câmaras, o custo é trinta vezes maior. No entanto, o custo adicional dos LEDs-UV em relação às lâmpadas fluorescentes negras é facilmente compensado pela economia realizada nos custos de capital (aquisição do equipamento) e de operação (consumo energético).Em suma, pelo menos no caso da degradação da nitrofurantoína pelo processo foto-Fenton, os LEDs-UV mostraram-se substitutos vantajosos das lâmpadas fluorescentes negras, tradicionalmente utilizadas.
The goal of this research was to study the degradation, by the photo-Fenton process, of a model-pollutant (an antibiotic fromthe nitrofurans group: nitrofurantoin), using UV-LEDs instead of the lamps traditionally used, i.e. black fluorescent lamps. Two irradiation chambers were compared, each one of them with a type of light source, regarding: removal percentage, ecotoxicity (Lactuca sativa), antimicrobial activity (Escherichia coli), capital costs (equipment), operating costs (energy consumption), and light sources costs, as well as the space the chambers occupy.The degradation experiments were performed and optimized by experimental design, using the Response Surface Methodology, and obtaining the optimum concentrations of nitrofurantoin, ferric ions, and hydrogen peroxide, for each of the chambers. The studied chambers showed similar performances regarding nitrofurantoin removal (more than 95% in 15 min), besides the generation of no ecotoxic products (Lactuca sativa) and the biological inactivation (Escherichia coli) of the drug. The irradiation chamber with UV-LEDs is compact,cheaper (it is half of the price of the other one), and it is four times more efficient in terms of electric consumption. The sole disadvantage found was the cost of the UV-LEDs. Taking into consideration the number of LEDs and black fluorescent lamps used in the chambers, thiscost is 30 times greater. However, the additional cost of the UV-LEDsin comparison to black fluorescent lamps is easily compensated by the savings in capital costs (equipment acquisition) and operating costs (electric consumption). In summary, at least regarding the nitrofurantoin degradation by the photo-Fenton process, the UV-LEDs proved to beworthwhile alternatives for black fluorescent lamps, which are traditionally used.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The occurrence and identification of organic microcontaminants has attracted the interest of many researchers for the development and improvement in processes for the removal of these contaminants from effluents. In general, degradation of microcontaminants by conventional methods is very difficult, because of the low concentrations that they are found. Thus, the photo Fenton process and Ultraviolet Radiation (UV) has been a promising alternative for the removal of such water contamination. This study aims to perform the investigation of degradation, in effluent, of atrazine (ATZ) using the photo Fenton process and degradation of the pharmaceuticals propranolol (PRO) and metronidazole (MET) using UV radiation. In the ATZ (0,1 mg L-1) degradation study, UV-A photo Fenton process was used (H2O2= 5,0 mg L-1 e Fe2+ = 5,0 mg L-1), achieving a microcontaminant degradation of about 62 %, and the UV-C photo-Fenton process (H2O2 = 5,0 mg L-1 e Fe2+ = 5,0 mg L-1), reached about 98% of ATZ degradation. The analysis of organic matter removal during the photo Fenton treatment showed no significant change in the studied parameters. In the UV photolysis degradation study of the pharmaceuticals solutions (100 mg L-1) a degradation of 35% (PRO) and 50% (MET) was obtained after 8 hours of treatment, whereas using solar radiation a degradation of 36% (PRO) and 16% (MET) were obtained. From the kinetic constants and half-lives calculated, it was found that direct photolysis using solar radiation was so effective as the system using UV-C radiation to promote photodegradation of PRO, and for the MET results showed that the pharmaceutical has a higher degradation rate when the UV-C radiation was employed.
O surgimento e a identificação dos microcontaminantes orgânicos têm atraído o interesse de inúmeros pesquisadores para o desenvolvimento e melhoria nos processos de degradação desses contaminantes de efluentes. Em geral, a degradação de microcontaminantes por processos convencionais é bastante dificultada, em razão das baixas concentrações que eles são encontrados. Desta forma, o processo foto Fenton e a Radiação Ultravioleta (UV) têm sido uma alternativa promissora na eliminação deste tipo de contaminação da água. O presente trabalho teve como objetivo realizar o estudo da degradação, em efluentes, da atrazina (ATZ) utilizando o processo foto Fenton e da degradação dos fármacos propranolol (PRO) e metronidazol (MET) utilizando radiação UV. No estudo da degradação da ATZ (0,1 mg L-1) foi utilizado o processo foto Fenton UV-A (H2O2 = 5,0 mg L-1 e Fe2+ = 5,0 mg L-1), sendo obtida uma degradação do microcontaminante de cerca de 62%, e o processo foto Fenton UV-C (H2O2 = 5,0 mg L-1 e Fe2+ = 1,0 mg L-1), obtendo 98 % de degradação da ATZ. A análise da remoção da matéria orgânica durante o tratamento foto Fenton mostrou que não houve alteração significativa nos parâmetros estudados. No estudo da degradação por fotólise UV das soluções dos fármacos (100 mg L-1), foram obtidas taxas de degradação de 35% (PRO) e 50% (MET), após 8 horas de tratamento, enquanto que no processo utilizando a luz solar foram obtidos taxas de degradação de 36% (PRO) e 16% (MET). A partir das contantes cinéticas e das meias-vidas obtidas, foi verificado que a fotólise direta utilizando a radiação solar é tão eficaz quanto o sistema utilizando radiação UV-C para promover a fotodegradação do PRO, e para o MET, os resultados mostraram que o fármaco apresenta uma maior taxa de degradação quando a radiação UV-C foi utilizada. Palavras-chave: Microcontaminantes; Radiação UV; foto Fenton O surgimento e a identificação dos microcontaminantes orgânicos têm atraídoo interesse de inúmeros pesquisadores para o desenvolvimento e melhoria nosprocessos de degradação desses contaminantes de efluentes. Em geral, adegradação de microcontaminantes por processos convencionais é bastantedificultada, em razão das baixas concentrações que eles são encontrados. Destaforma, o processo foto Fenton e a Radiação Ultravioleta (UV) têm sido umaalternativa promissora na eliminação deste tipo de contaminação da água. Opresente trabalho teve como objetivo realizar o estudo da degradação, em efluentes,da atrazina (ATZ) utilizando o processo foto Fenton e da degradação dos fármacospropranolol (PRO) e metronidazol (MET) utilizando radiação UV. No estudo dadegradação da ATZ (0,1 mg L-1) foi utilizado o processo foto Fenton UV-A (H2O2 =5,0 mg L-1 e Fe2+ = 5,0 mg L-1), sendo obtida uma degradação do microcontaminantede cerca de 62%, e o processo foto Fenton UV-C (H2O2 = 5,0 mg L-1 e Fe2+ = 1,0 mgL-1), obtendo 98 % de degradação da ATZ. A análise da remoção da matériaorgânica durante o tratamento foto Fenton mostrou que não houve alteraçãosignificativa nos parâmetros estudados. No estudo da degradação por fotólise UVdas soluções dos fármacos (100 mg L-1), foram obtidas taxas de degradação de 35%(PRO) e 50% (MET), após 8 horas de tratamento, enquanto que no processoutilizando a luz solar foram obtidos taxas de degradação de 36% (PRO) e 16%(MET). A partir das contantes cinéticas e das meias-vidas obtidas, foi verificado quea fotólise direta utilizando a radiação solar é tão eficaz quanto o sistema utilizandoradiação UV-C para promover a fotodegradação do PRO, e para o MET, osresultados mostraram que o fármaco apresenta uma maior taxa de degradaçãoquando a radiação UV-C foi utilizada.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The solar photo-Fenton process appears as an attractive alternative to post-treatment of landfill leachate to reduce the recalcitrant organic load of these effluents and, at the same time, to reduce energy costs of treatment by the use of a clean, renewable and free energy source. In this way, the present study aimed to evaluate the efficiency of the solar photo- Fenton process in the final physicochemical and toxicological quality of the biologically pretreated leachate from the landfill of João Pessoa city using a pilot-scale photoreactor. Initially, the operating conditions were investigated (flow, reaction time and pH adjustment) for the solar photo-Fenton process in pilot-scale. For this, three tests were performed with different flow rates (test1=65L.min-1, test2 = 48L.min-1, test3 = 35L.min-1). Then, the test 4 was carried to evaluate the reaction time process (60, 120 and 180 minutes) and the influence of pH adjustment (pH8) in the samples after the process. Under defined conditions, the efficiency of the solar photo-Fenton process was evaluated in terms of physicochemical and toxicological parameters (test 5). The influence of solar photolysis treatment was also observed. As a result, it was verified that the flow does not interfere directly in the removal of COD; then the minimum flow (35L.min-1) was adopted. In 60 minutes of reaction, it was possible to obtain high COD (76.1%) and color (93.45%) removals, so, this time was chosen for the process. The pH adjustment procedure was adopted to standardize the phototreated samples, since it increased the COD removal around 4%. In general, there was no change in the physicochemical characteristics of the leachate after the solar photolysis process. The solar photo-Fenton process provided high removals of color (87.5%), COD (81.7%) and recalcitrance, in terms of BOD5/COD (which increased from 0.12 to 0.32) and aromatic compounds (A254: 87,1% and A280: 87,74%). In addition, the solar photo-Fenton process reduced 76% of the leachate phytotoxicity on the lettuce plant (Lactuca sativa), in terms of EC50. In that way, it can be concluded that the solar photo-Fenton process was efficient when applied in pilot-scale, acting as an interesting post-treatment alternative for reduction of COD, color, recalcitrance and toxicity from landfill leachate.
O processo foto-Fenton solar surge como uma alternativa atrativa no pós-tratamento de lixiviados de aterros sanitários capaz de atuar na redução da carga orgânica recalcitrante desses efluentes e, ao mesmo tempo, possibilitar a miminização dos custos energéticos do tratamento pela utilização de uma fonte limpa, renovável e gratuita de energia. Dessa forma, a presente pesquisa objetivou avaliar a eficiência do processo foto-Fenton solar na qualidade físico-química e toxicológica final do lixiviado proveniente do sistema de tratamento biológico do Aterro Sanitário Metropolitano de João Pessoa (ASMJP) usando um fotorreator em escala piloto. Inicialmente, foram investigadas as condições operacionais (vazão, tempo de reação e ajuste do pH) para o processo foto-Fenton solar, em escala piloto. Para isso, foram realizados três testes com vazões diferenciadas (teste1=65L.min-1; teste2=48L.min-1; teste3=35L.min-1). Foi realizado ainda o teste 4, onde o tempo de reação (60, 120 e 180 minutos) foi investigado, bem como verificou-se a influência do ajuste de pH (pH8) nas amostras após o tratamento. Sob as condições definidas, a eficiência do processo foto-Fenton solar foi avaliada em termos de parâmetros físicos, químicos e toxicológicos (teste 5). A influência da fotólise solar no tratamento também foi verificada. Como resultados, pôde-se observar que a vazão não interferiu diretamente na remoção de DQO das amostras, adotou-se então a vazão mínima estudada (35L.min-1). Observou-se ainda que em 60 minutos de reação já foi possível obter elevados percentuais de remoção de DQO (76,1%) e cor (93,45%), sendo portanto o tempo escolhido para o tratamento. O procedimento de ajuste de pH foi adotado para padronização das amostras fototratadas, visto que ele elevou a remoção de DQO em torno de 4%. Em geral, não se verificou alteração nas características físico-químicas do lixiviado após a fotólise solar. O processo foto-Fenton solar proporcionou elevadas eficiências de remoção de cor (87,5%), DQO (81,7%) e recalcitrância, em termos de DBO5/DQO (que aumentou de 0,12 para 0,32) e redução de compostos aromáticos (A254: 87,1% e A280: 87,74%). Além de que, reduziu em 76% a elevada fitotoxicidade do lixiviado sobre a espécie Lactuca sativa (alface), em termos de CE50. Assim, pode-se concluir que o processo foto- Fenton solar foi eficiente quando aplicado em escala piloto sendo uma alternativa de póstratamento interessante na redução de DQO, cor, recalcitrância e toxicidade do lixiviado.

Cilj  ove  doktorske  disertacije  je  bio  razvoj  brzih  i  pouzdanih  voltametrijskih  metoda zasnovanih na primeni jednostavnih i savremenih elektroda/senzora na bazi ugljeničnih materijala (ugljenične  paste  napravljene  od  grafitnog  praha  i  parafinskog  ulja  i  štampanih  ugljeničnih elektroda)  za  određivanje  H ₂O₂ u  odabranim  složenim  model  i  realnim  uzorcima.  U  tu  svrhu, ispitana je primenljivost različitih radnih elektroda. Amperometrijska  metoda  zasnovana  na  elektrodi  od  ugljenične  paste  (CPE)  zapreminski modifikovane  sa  5%  (m:m)  MnO2 je,  pri  optimizovanim  uslovima  i  pri  radnom  potencijalu  od 0,40 V  u  odnosu  na  zasićenu  kalomelovu  elektrodu  (ZKE)  u  fosfatnom  puferu  pH  7,50  kao pomoćnom elektrolitu, omogućila kvantifikaciju H ₂O₂ u opsegu koncentracija od 1,4 do 65 µg mL -1 sa  relativnom  standardnom  devijacijom  (RSD)  manjom  od  10%.  Ova  metoda  je  primenjena  za određivanje sadržaja H ₂O₂ u uzorcima podzemne vode iz centralnog Banata (Pokrajina Vojvodina, Srbija)  tretirane  Fentonovim  (Fe ²⁺ i  H ₂O₂ )  i  Fentonu-sličnim  (Fe ³⁺ i  H ₂O₂ )  reagensima  u  cilju uklanjanja  prirodnih  organskih  materija  (POM)  pri  čemu  su  korišćene  različite  početne koncentracije  gvožđa  i  različiti  odnosi  molarnih  koncentracija  gvožđa  i  H ₂O₂ .  Utvrđeno  je  da oksidaciono  stanje  gvožđe  (Fe ²⁺ ili  Fe ³⁺)  i  molarni  odnos  jona  Fe  i  H ₂O₂ utiču  na  stepen potrošnje/razgradnje  H ₂O₂u  podzemnoj  vodi  sa  visokim  sadržajem  POM.  Takođe,  u  slučaju Fentonu-sličnog  procesa,  za  sve  početne  koncentracije  Fe ³⁺ i  H ₂O_{2 ,}  signifikantna  količina  H ₂O₂ ostaje  neiskorišćena,  što  ukazuje  na  nižu  efikasnost  ovakvog  sistema u  poređenju  sa  Fentonovim procesom.Štampana  ugljenična  elektroda  (SPCE)  zapreminski  modifikovana  sa  MnO 2 kao medijatorom  je  primenjena  za  određivanje  sadržaja  H ₂O₂ u  toku  Fentonovog  (Fe ²⁺ ,  H₂O₂ )  i vidljivom  svetlošću  potpomognutog  foto-Fentonovog  (Fe ²⁺ ,  H ₂O₂ ,  hν)  procesa  uklanjanja neonikotinoidnog  insekticida  acetamiprida  (ACT).  Pri  optimizovanim  uslovima  (radni  potencijal 0,40  V  u  odnosu  na  ZKE,  fosfatni  pufer  pH  7,50  kao  pomoćni  elektrolit)  amperometrijskog određivanja  H ₂O₂ ,  postignuta  je  linearnost  u  opsegu  koncentracija  0,01–1,24  mmol  L-1(0,34– 42,2 µg mL -1) i vrednost RSD nije prelazila 4,2%. U ispitivanimuzorcima (nakon odgovarajućegpodešavanja pH vrednosti od 2,8 do 7,5 odmah nakon  uzorkovanja radi stopiranja ili maksimalnog usporavanja  procesa  oksidacije,  filtriranja,  zamrzavanja  i  odmrzavanja  neposredno  pre  merenja) sadržaj  H ₂O₂ je  određen  metodom  standardnog  dodatka  analiziranjem  odgovarajućih amperometrijskih  krivi.  Paralelna  HPLC-DAD  merenja  su  vršena  u  cilju  praćenja koncentracije/uklanjanja ACT. U slučaju foto-Fentonovog procesa (početne koncentracije 0,31; 2,0 i 3,0 mmol L -1 (70,0; 111,7 i 102,1 µg mL -1 ) za ACT, Fe²⁺ i H ₂O₂, redom) nakon 10 min H ₂O₂ je izreagovao, a može se smatrati da je ACT uklonjen nakon 5 min. U toku Fentonovog procesa ACT je  uklonjen  nakon  20  min  tretmana  i  oko  10%  početne  koncentracije  H ₂O₂ je  ostalo  u  sistemuneiskorišćeno.CPE  je  površinski  modifikovane  kompozitom  na  bazi  nanočestica  Pt  (<  5  nm)  i grafitizovanog  ugljenika  (Pt-C,  10%  Pt  na  Vulkanu  XC72)   etodom  nanošenja  kapi. Nemodifikovana  CPE  i  modifikovana  (Pt-C/CPE)  su   okarakterisane  primenom  SEM/EDS  i  CV merenja.  Pt-C/CPE  je  pokazala  izuzetne  elektrokatalitičke  osobine  u  pogledu  elektrohemijskeredoks  reakcije  H₂O₂ u  poređenju  sa  nemodifikovanom  CPE  u  fosfatnom  puferu  (0,1 mol  L -1 ;pH 7,50),  a  takođe  i  u  acetatnom  puferu  (0,1  mol  L -1 ;  pH  4,50)  kao   pomoćnim  elektrolitima. Prilikom  amperometrijskog  određivanja  H ₂O₂ primenom  Pt-C/CPE  u  model  sistemima, zadovoljavajuća linearnost je postignuta u koncentracionom opseguH₂O₂od 0,15 do 1,45 µg mL -1 ,dok su vrednosti GO iznosile 0,06 µg mL -1 (pH 7,50, radni potencijal 0,20 V) i 0,10 µg mL -1 (pH4,50,  radni  potencijal  0,50  V).  Optimizovane  analitičke  metode  su  primenjene  za  određivanje sadržaja H ₂O₂ u komercijalno dostupnim proizvodima za ličnu negu: rastvoru za dezinfekciju (pH 7,50)  i  rastvoru  za  čišćenje  kontaktnih  sočiva  (pH  4,50).  Amperometrijski  dobijeni  rezultati  su  u dobrom  slaganju  sa  rezultatima  dobijenim  primenom  tradicionalne  spektrofotometrijske  metode bazirane  na  titanijum-sulfatu  kao  reagensu  sa  određenim  koncentracijama  2,91%  i  2,94%  zadezinfekcioni rastvor i 3,04% i 3,17% za rastvor zakontaktna sočiva, redom. RSD je bila manja od 2%.  Postignuti  rezultati  su  u  dobrom  slaganju  sa  sadržajem  H₂O₂ deklarisanim  od  strane proizvođača (3%) u oba ispitivana uzorka. Pt-C/CPE je takođe testirana za praćenje koncentracije H₂O₂ u rastvoru za kontaktna sočiva u toku procesa njegove neutralizacije/razgradnje. Nakon 6 h procesa neutralizacije, 24,68  µg mL -1 je bila određena koncentracija H ₂O_{2 ,} što je ispod dozvoljeneH₂O₂ koncentracije u rastvoru za kontaktna sočiva imajući u vidu granicu koja izaziva iritaciju oka. CPE  je  površinski  modifikovana  višezidnim  ugljeničnim  nanocevima  (MWCNT)  i kompozitima MnO 2 -MWCNT ili Pt-MWCNT metodom nanošenja kapi radi pripreme jednostavnih, osetljivih i pouzdanih voltametrijskih senzora za  određivanje H ₂O₂ u odabranom uzorku. Rezultati SEM/EDS  analize  kompozitnih  materijala  su  potvrdili da  su  medijatori,  čestice  MnO 2 i  Pt, nasumično  raspoređeni na površini MWCNT i zastupljeni sa blizu 5% (m:m) u kompozitu izraženopreko Mn i Pt. CV merenja su vršena sa pripremljenim radnim elektrodama u acetatnom (pH 4,50), fosfatnom  (pH  7,50)  i  boratnom  (pH  9,18)  puferu  kako  bi  se  okarakterisalo  osnovno elektrohemijsko  ponašanje  H ₂O₂ i  odabrali  pogodni  radni  potencijali  za  amperometrijsko određivanje ovog ciljnog analita. Pt- WCNT/CPE je primenljiva za rad kako u fosfatnom puferu pH  7,50  tako  i  u  acetatnom  puferu  pH  4,50  V  kako  pri  negativnim  tako  i  pri  pozitivnim  radnimpotencijalima, pri  čemu su vrednosti RSD uglavnom ispod 2,5%. U slučaju MnO 2-MWCNT/CPE, na  potencijalu  0,30  V  i  višim  vrednostima,  oksidacioni  signali  H₂O₂ su  signifikantni  u  blago alkalnoj sredini (pH 7,50), pri pH 4,50 ova elektroda pokazuje nezadovoljavajuće ponašanje, dok  pri pH 9,18 ima prihvatljive performanse. Granice određivanja (GO) su bile u oblasti µg mL -1 . H ₂O₂ je  određen  u  spajkovanom  uzorku  mleka  metodom  standardnog  dodatka  nakon  odgovarajuće pripreme  uzorka  (pH  podešavanje  i  centrifugiranje)  i  primenom  optimizovane  amperometrijske procedure (acetatni pufer pH 4,50, radni  potencijal-0,75 V) koristeći Pt-MWCNT/CPE kao radnu elektrodu. RSD za tri  ponovljena merenja je iznosila 2,5%, dok je prinos metode bio nešto veći od 71%.Kompozitni materijali koji se sastoje od MWCNT i  čestica na bazi Pd (Pd-MWCNT) ili Pt (Pt-MWCNT) su primenjeni za pripremu zapreminski modifikovanih SPCE (Pd-MWCNT-SPCE i Pt-MWCNT-SPCE)  i  površinski  modifikovane  SPCE  (Pd-MWCNT/SPCE).  Ove  elektrode,  kao  i nemodifikovana  SPCE  i  MWCNT-SPCE,  su  okarakterisane primenom  CV  i  amperometrije  u fosfatnom puferu pH 7,50 radi određivanja H ₂O₂ . Pd-MWCNT-SPCE i Pd-MWCNT/SPCE su se pokazale  pogodnim  za  određivanje  H ₂O₂ na  radnim  potencijalima  između  -0,50  i  0,50  V,  a  PtMWCNT-SPCE na ispitivanim radnim potencijalima od -0,80 do 0,70 V. Ove  elektrode su zatim modifikovane  enzimom  glukoza  oksidazom  (GOx)  metodom  nanošenja  kapi  rastvora  GOx  i Nafion ® -a  na  njihovu  površinu,  pri  čemu  je  optimizovana  količina  nanetog  biofilma.  GOx/PdMWCNT-SPCE  je  pokazala  bolje  analitičke  performanse  za  određivanje  glukoze  u  poređenju  sa GOx/Pd- WCNT/SPCE.  Kao  optimalan  radni  potencijal  GOx/Pd-MWCNT-SPCE  je  odabranavrednost  potencijala  -0,40  V  u  odnosu  na  ZKE,  sa  zadovoljavajućom  linearnošću  u  ispitivanom opsegu  koncentracija  glukoze  od  0,16  do  0,97  mmol  L -1 (od  29,1  do  174  µg  mL -1),  dok  je  GO iznosila 0,14 mmol L -1 (25 µg mL-1 ). Optimizovana metoda zasnovana na GOx/Pd-MWCNT-SPCE je  uspešno  primenjena  za  određivanje  glukoze  u  uzorku  livadskog  meda.  Dobijeni  rezultati  su  u dobroj  saglasnosti  sa  onima  dobijenim  primenom  komercijalno  dostupnog  aparata  za  merenje glukoze. Pogodan radni potencijal za GOx/Pt-MWCNT-SPCE je bio -0,50 V u odnosu na ZKE, pri čemu je zadovoljavajuća linearnost postignuta u ispitivanom opsegu koncentracija glukoze od 65,8 do 260,6 µg mL -1 , sa GO 35 µg mL -1 . Optimizovana metoda zasnovana na GOx/Pt-MWCNT-SPCE je  uspešno  primenjena  za  određivanje  glukoze  u  u  uzorku  belog  grožđa  i  uzorku  tableta (Traubenzucker-bonbons),  pri  čemu  su  dobijeni  rezultati  u  dobroj  saglasnosti  sa  rezultatima dobijenim primenom Accu-Chek aparata.Na  osnovu  dobijenih  rezultata  može  se  zaključiti  da  su  razvijene  analitičke  metode  pre svega jednostavne, pouzdane i pogodne za dobijanje brzih informacija o sadržaju H ₂O₂ u različitim tipovima  uzoraka.  Svakako  odabir  pogodne  radne  elektrode,  kao  i  optimizacija  eksperimentalnih uslova su ključni faktori za uspešno određivanje H ₂O₂
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The aim of this doctoral dissertation was the development of fast and reliable voltammetric methods  based  on  the  application  of  simple  and  contemporary  electrodes/sensors  based  on carbonaceous materials (carbon paste made of graphite powder and paraffin oil and screen printed carbon electrodes) for the determination of H  ₂ O₂ in the selected complex model and real samples.For this purpose, applicability of different working electrodes was investigated.The  amperometric  method  based  on  carbon  paste  electrode  (CPE)  bulk- modified     with 5% (m:m) MnO 2 , under optimized conditions, with a working potential of 0.40 V vs. the saturated calomel  elect rode  (SCE)  and  a  phosphate  buffer  solution  (pH  7.50)  as  supporting  electrolyte, enabled the quantitation of H  ₂ O₂in the concentration interval from 1.4 to 65 µg mL −1 with a relative standard deviation (RSD) of less than 10%. This meth od was applied for the determination of the H ₂ O₂ consumption  in  samples  of  groundwater  fro m  the  Central  Banat  region  (Province  of Vojvodina, Serbia) treated by the Fenton (Fe ²⁺ and H ₂O₂ ) and Fenton-  like (Fe ³⁺and H ₂O₂ ) reagents to remove natural organic matter (NOM) at  differentinitial concentrations of iron species, and of their molar ratios to the initial concentration of H₂O₂ . It was found that the form of Fe (Fe ²⁺ or Fe ³⁺ )and the molar  ratio to H ₂O₂influenced the degree of the H ₂O₂ decomposition in the groundwater with high NOM content. Besides, in the case of the Fenton-like process, for all initial doses of Fe ³⁺ and H  ₂ O₂, a sign ificant amount of H  ₂ O₂ remained unused, whi ch also indicates a lower efficiency of such system compared to the Fenton process. Screen  printed  carbon  electrode  (SPCE)  bulk-modified  with  MnO  ₂ as  a  mediator  was applied  for  amperometric  determination  of  the  H  ₂ O₂ content  during  the  Fenton  (Fe ²⁺ ,  H  ₂ O₂ )  and  visible  light-assisted ,  photo-Fenton  (Fe ²⁺  ,  H  ₂ O₂ ,  hν)   based  removal  of  neonicotinoid  insecticide acetamiprid (ACT). Under  optimized conditions (working potential of 0.40 V vs. SCE, phosphate buffer  pH  7.50  as  supporting  electrolyte)  amperometric  determination  of  H  ₂ O₂ showed  a  linear dynamic range from 0.01 to 1.24 mmol L -1 (from 0.34 to 42.2 µg mL -1) and the RSD did not exceed 4.2%. In the investigated samples (after appropriate pH adjustment from 2.8 to 7.5 instantly after the sampling  to stop or maximum decelerate the oxidation processes, filtering, and storage of the deep- frozen sample with defrosting immediately before the measurements) the H  ₂ O₂  contents were determined by the standard addition method by analyzing the corresponding amperometric curves. Parallel HPLC-DAD measurements were performed to monito r the concentration/removal of ACT. In the case of the photo- Fenton process (initial concentrations: 0.31; 2.0 and 3.0 mmol L -1 (70.0; 111.7 and 102.1 µg mL -1 ) of ACT, Fe ²⁺ and H  ₂ O₂, respec tively) after 10 min of irradiation H  ₂ O₂ was  consumed  and  it  can  be  consi dered  that  ACT  was  removed  after  5  min.  During  the  Fenton process ACT was removed after 20 min of treatment and around 10% of the initial concentration of the H 2O2 remained still unused.CPE  was  surface  modified  with  a  composite  of  Pt  nanoparticles  (<  5  nm)  on  graphitized carbon (Pt-C, 10% Pt on Vulcan XC72) by simply dropcoating method. The unmodified CPE and the  modified  one  (Pt-C/CPE)  were  characterized  by   EM/EDS  and  CV  measurements.  The  PtC/CPE showed remarkable electrocatalytic propertiestoward the electrochemical redox reaction of H ₂ O₂ compared to  modified CPE in phosphate buffer (0.1 mol L -1 ; pH 7.50), as well in acetatebuffer  (0.1 mol  L -1 ; pH .50) supporting  electrolytes. Amperometry of  H2O2 in the concentration range from 0.15 to 1.45 µg mL -1 with the Pt-C/CPE showed acceptable linearity, while the obtained values of LOQs were 0.06 µg mL -1  (pH 7.50, working potential 0.20 V) and 0.10 µg mL -1 (pH 4 .50, working potential 0.50 V). The proposed analytical  methods were applied to the determination of the H 2O2 content in commercially available personal care products; i.e., disinfection (pH 7.50) and contact lens cleaning solutions (pH 4.50). The obtained amperometric results are in good agreement with those measured by traditional titanium sulfatereagent based spectrophotometric method with determined concentrations as 2.91% and 2.94%  for the disinfection product, and 3.04% and 3.17% for the contact lens solution, respectively. RSD was lower than 2%. The obtained results are in a good agreement with the amounts of the H  ₂ O₂ declared by producers (3%) in the both investigated samples. The Pt-C/CPE was also tested for monitoring of the H  ₂ O₂ residual concentration in contact lens  solution  during  its  neutralization/decomposition  rocess.  At  6  h  of   neutralization  treatment 24.68 µg mL -1 of the H  ₂ O₂ was  determined which is almost half of the allowedH2 O2 concentration in the case of the contact lens solution concerningthe limit of eye irritation. CPE  was  surface   modified  with  multiwalled  carbon  nanotubes  (MWCNT)  and  with composites of MnO ₂ -MWCNT or Pt-MWCNT by drop coating method to prepare simply, sensitive and reliable volta mmetric sensors for the determination of H  ₂ O₂ in selected sample. The results of the  SEM/ EDS  analysis  of  composite  materials  have  confirmed  that  the  mediators,  MnO ₂ and  Pt  articles, are randomly distributed on the surface of MWCNT and represent nearly 5% (m:m) of the composite expressed as Mn and Pt. CV measurements were performed  with prepared electrodes in acetate  (pH  4.50),  phosphate  (pH  7.50)  and  borate  (pH  9.18)  buffers  to  characterize  the  basic electrochemical  behavior  of  H  ₂ O₂ and  to  select  the  working  potentials  suitable  for  amperometric determination  of  this  target  analyte.  The  Pt-MWCNT/CPE  performs  well  in  phosphate  buffer pH .50 and acetate buffer solution pH 4.50 in the  negative as well as in the positive polarization range with RSD mainly lower than 2.5%. In case of MnO ₂ -MWCNT/CPE at  0.30 V and above the H ₂ O₂ oxidation signal is rem arkable in slightly alkaline media (pH 7.50), at pH 4.50 this electrode showed poor behavior and at pH 9.18 offered acceptable performance. LOQs were in the µg mL -1 concentration  range.  H ₂ O₂ was  determined  in  a  spiked  milk  sample  by  standard addition  method after  appropriate  sample  preparation  (pH  adjustment and  centrifugation)  and  using  optimized amperometric p rocedure (acetate buffer pH 4.50, working potential -0.75 V) by Pt-MWCNT/CPE as a working electrode. RSD for three repeated measurements was 2.5%, while the recovery of the method was a bit higher than 71%. The  composite  materials  consisting  of  MWCNT  and  Pd  (Pd-MWCNT)  or  Pt  containing particles  (Pt-WCNT)  were  applied  to  the  preparation  of  bulk- modified  SPCEs  (Pd-MWCNTSPCE and Pt-MWCNT-SPCE) and surface modifiedSPCE (Pd- MWCNT/SPCE). These electrodes, as well as unmodified SPCE and MWCNT-SPCE,  were characterized by CV and  amperometry  in phosphate  buffer  solution  of  pH  7.50  for  the  H  ₂ O₂ determination.  Pd-MWCNT-SPCE  and  PdMWCNT/SPCEare convenient for the etermination of H 2O2 at working potentials from -0.50 to 0.50 V, and Pt-MWCNT-SPCE at investigated working potentials in the range from -0.80 to 0.70 V. These electrodes were then modified with glucose  oxidase (GOx) by drop coating a solution of GOxand Nafion ® on their surface, whereby the applied amount of biococktail was optimized. GOx/PdMWCNT-SPCE  showed  better  analytical  performance  for  glucose  determination  in  comparison with  GOx/Pd-MWCNT/SPCE.  The  optimal  working  potential  for  GOx/Pd-MWCNT- SPCE  was -0.40 V vs. SCE and  satisfactory linearity was obtained in the investigated glucose concentration range from 0.16 to 0.97 mmol L -1 (from 29.1 to 174  µg mL -1 ), hile the LOQ was 0.14 mmol L -1 (25 µg mL -1 ). The optimized method based on GOx/Pd-MWCNT-SPCE was successfully applied to the determination of glucose in multifloral honey sample.  The results are in a good agreement with those  obtained by commercially available equipment for determination of glucose. Optimal working potential  for  GOx/Pt-MWCNT-SPCE  was  -0.50  V  vs.  SCE,  and  the   satisfactory  linearity  was obtained in the investigated concentration range ofglucose from 65.8 to 260.6  µg mL -1 , with LOQ of 35  µg mL -1 . The optimized method based on GOx/Pt- MWCNT-SPCE was successfully applied for determination of glucose in white grape and glucose tablets (Traubenzucker-bonbons) samples, whereby  the  obtained  results  were  in  a  good  agreement  with  the  results  obtained  by  Accu-Chek device. Based on the results, the developed analytical methods are first of all simple, reliable and suitable  for  obtaining  fast  information  about  the  content  of  H ₂O₂ in  different  types  of  samples. Certainly the selection of a suitable working electrode, as well as the optimization of experimental conditions are key factors for the successful determination of H₂O₂ .

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O presente trabalho aborda a degradação simultânea de dois contaminantes emergentes, o plastificante bisfenol A (BPA) e o fármaco carbamazepina (CBZ), aplicando-se processos oxidativos avançados (POA), particularmente o processo foto-Fenton. Durante os ensaios de degradação, o BPA e a CBZ foram determinados por cromatografia líquida de alta eficiência (CLAE) em uma única análise, utilizando dois detectores acoplados em série, o detector de fluorescência (FLU) para o BPA e detector de arranjo de diodos (DAD) para a CBZ. Foi necessária a otimização das condições do método cromatográfico, tais como, composição da fase móvel, 50% etanol-água, vazão, 0,500 mL min-1, comprimento de onda de excitação e emissão para o BPA, 277 e 300 nm nesta ordem, e absorção para a CBZ de 286 nm ou 211 nm. Após a construção da curva analítica foram determinados os parâmetros analíticos como: linearidade, limites de detecção e quantificação. Os ensaios de degradação foram efetuados em duas matrizes distintas, água e efluente de estação de tratamento de esgoto, coletado antes do lançamento nos rios, objetivando desenvolver um método de degradação em baixas concentrações em amostras reais. Pela complexidade da matriz foi necessário fazer o “clean up” das amostras por extração em fase sólida (EFS) nas alíquotas retiradas durante as degradações no efluente. A faixa de recuperação da EFS foi avaliada em três níveis e atingiu de 82 a 84% para o BPA e de 92 a 99% para a CBZ. A velocidade de degradação tanto de BPA como de CBZ foi influenciada pela matriz, pois foi maior em água do que no efluente. O tempo de degradação em água foi de 60 minutos e em efluente de 90 minutos. A degradação de BPA atingiu 88% em água e 77% em efluente, enquanto que de CBZ atingiu 95% em água e 61% em efluente. A remoção de carbono orgânico dissolvido (COD) nas amostras de efluente foi avaliada, porém as concentrações de Fe(III) e H2O2 utilizadas, 12,0 μmol L-1 e 300 μmol L-1 nesta ordem, não foram suficientes para degradar a matéria orgânica do efluente, mas foram suficientes para a degradação dos compostos alvos na concentração de 250 μg L-1.

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Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
Effluents from pesticide industries have great difficulty to decontaminate the environment and, moreover, are characterized by high organic charge and toxicity. The research group Center for Chemical Systems Engineering (CESQ) at the Department of Chemical Engineering of Polytechnical School of University of S?o Paulo and Department of Chemical Engineering, Federal University of Rio Grande do Norte have been applying the Advanced Oxidation Processes (AOP's) for the degradation of various types of pollutants. These processes are based on the generation of hydroxyl radicals, highly reactive substances. Thus, this dissertation aims to explore this process, since it has been proven to be quite effective in removing organic charge. Therefore, it was decided by photo-Fenton process applied to the degradation of the fungicide Thiophanate methyl in aqueous system using annular reactor (with lamp Philips HPLN 125W) and solar. The samples were collected during the experiment and analyzed for dissolved organic carbon (TOC) using a Shimadzu TOC (Shimadzu 5050A e VCP). The Doehlert experimental design has been used to evaluate the influence of ultraviolet radiation, the concentrations of methyl thiophanate (C12H14N4O4S2), hydrogen peroxide (H2O2) and iron ions (Fe2+), among these parameters, was considered the best experimental conditions, [Fe2+] = 0.6 mmol/L and [H2O2] = 0.038 mol/L in EXP 5 experiment and in SOL 5 experiment, obtaining a percentage of TOC removal of 60% in the annular reactor and 75% in the solar reactor
Os efluentes das ind?strias de agrot?xicos apresentam grande dificuldade quanto ? sua descontamina??o no meio ambiente e, al?m disso, s?o caracterizados por possu?rem alta carga org?nica e toxicidade. O grupo de pesquisa do Centro de Engenharia de Sistemas Qu?micos (CESQ) do Departamento de Engenharia Qu?mica da Escola Polit?cnica da Universidade de S?o Paulo e do Departamento de Engenharia Qu?mica da Universidade Federal do Rio Grande do Norte vem aplicando os Processos Oxidativos Avan?ados (POA) ? degrada??o de diversos tipos de poluentes. Estes processos s?o baseados na gera??o de radicais hidroxila, subst?ncias altamente reativas. Desta forma, buscou-se explorar esse processo, j? que o mesmo vem se apresentando bastante eficaz na remo??o de carga org?nica. Portanto, decidiu-se pelo processo foto- Fenton aplicado na degrada??o do fungicida tiofanato met?lico em sistema aquoso, utilizando reator anular (com l?mpada Philips, HPLN de 125W) e solar. As amostras foram coletadas durante o experimento e analisadas quanto ao teor de carbono org?nico dissolvido (COT) utilizando um analizador TOC (Shimadzu 5050A e Shimadzu VCH). O planejamento experimental Doehlert utilizado para avaliar a influ?ncia da radia??o ultravioleta, das concentra??es do tiofanato met?lico (C12H14N4O4S2), do per?xido de hidrog?nio (H2O2) e dos ?ons de ferro [Fe2+]. Dentre estes par?metros, foram consideradas as melhores condi??es experimentais, sendo: [Fe2+] = 0,600 mmol/L e [H2O2] = 0,038 mol/L no experimento EXP 5 e no experimento SOL 5, obtendo um percentual de remo??o de COT de 60% no reator anular e de 75% no reator solar

碩士
國立聯合大學
環境與安全衛生工程學系碩士班
94
Chlorophenols constitute an important category of organic water pollutants that are highly toxic and are not readily biodegradable. Consequently, conventional treatment process is not very effective for removing chlorophenols from chemical effluents. In this study, a novel alternative – solar photo-Fenton process was used to treatment chlorophenols in water. The effect of Fenton oxidation of chlorophenols, including 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), and 2,4-dichlorophenol (2,4-DCP), promoted by solar irradiation was investigated. The parameters including solar light intensity, the dosage of H2O2, the dosage of Fe2+, and the ratio of H2O2/Fe2+/chlorophenol were examined. In addition, the variation of pH and ORP, dechlorination efficiency, and Fe3+-containing sludge production during chlorophenols oxidation were probed to realize intensely the assisted effect of solar irradiation on the degradation of chlorophenols in water. In this study, all experiments were carried out in batch mode. 1 mM of chlorophenol solution was prepared with tap water and used for each experiment. The dosage of H2O2 and Fe2+ was in the range of 2.5 mM ~ 20.0 mM and 0.2 mM ~ 1.0 mM, respectively. It was found that Fenton process irradiated by solar light improved significantly the COD removal and mineralization efficiency of chlorophenolsin water. Basically, a higher solar light irradiation on Fenton process showed an increased degradation efficiency of chlorophenols. Increasing initial H2O2 dosage was much more beneficinal for COD removal and mineralization efficiency than increasing initial Fe2+ dosage. This could be due to incessant photo-reduction reaction of Fe3+ (Fe(OH)2+) ion under solar irradiation, leading to a lower dosage of Fe2+ being sufficient to catalyze H2O2 for generating hydroxyl radicals in solution. Moreover, solar photo-Fenton reaction at higher initial Fe2+ dosage led to the formation of a brown turbidity in the reaction vessel, which may decreased the absorption of solar light and promoted the recombination of hydroxyl radicals. The COD removal and mineralization efficiency of chlorophenols were more than 90 % for an only 30 min treatment of solar photo-Fenton oxidation with an optimum [H2O2]0/[Fe2+]0/[chlorophenol]0 ratio of 12.5/0.3/1.0, 12.5/0.3/1.0, and 12.5/1.0/1.0 for 2-CP, 4-CP, and 2,4-DCP, respectively. Under the optimum conditions, the COD removal efficiency increased 58.7 %, 65.1 %, and 36.3 % for 2-CP, 4-CP, and 2,4-DCP, respectively as compared to those of Fenton process. At the same time, the mineralization efficiency increased 67.0 %, 68.3 %, and 55.9 % for 2-CP, 4-CP, and 2,4-DCP, respectively. In addition, the average oxidation state (AOS) values of chlorophenols solution treated by solar photo-Fenton process increased from -0.33, -0.33, and 0.00 to 1.86, 1.80, and 1.29 for 2-CP, 4-CP, and 2,4-DCP, respectively while no significant improvement for AOS values was found in Fenton process. It was believed that the promoted effects was mostly due to much higher H2O2 utilization efficiency, enhanced dechlorination and intermediates being more oxidized. Furthermore, the degradation and mineralization of chlorophenols was found to follow the pseudo-first order reaction kinetics. The rate constant of chlorophenols degradation increased more than 3 times as Fenton process assisted by solar irradiation. Under the same required degradation efficiency of chlorophenols, the amount of sludge generated by solar photo-Fenton process was less 50 % than that of Fenton process. On the strength of the results obtained in this study, a great increased in COD removal efficiency, mineralization efficiency and AOS value could be achieved by the combination solar irradiation and Fenton reaction with a lower Fe2+ dosage, leading to a lower sludge production. Accordingly, solar photo-Fenton process showed a potential application for the treatment of refractory pollutants such as chlorophenols in water.

碩士
國立中興大學
環境工程學系所
103
In recent years, people are paying more attention to emerging contaminants due to their great influence and the threat they may impose on the environment. Advanced oxidation processes (AOPs) can effectively produce strongly oxidizing and non-specific hydroxyl radical (．OH) to degrade pollutants, and thus are widely used to process various organic pollutants in the wastewater. This study uses antibiotic chlortetracycline (CTC) as the target pollutant and perform UV/H2O2 process, Fenton process and photo-Fenton process of AOP to degrade CTC and chemical oxygen demand (COD) in wastewater through changing different parameters (H2O2 concentration, Fe2+ concentration, light intensity). In addition, we also discuss the influences and differences between processes. The result shows that when concentration of CTC pollutant is 10 mg / L, the optimal treatment conditions for UV/H2O2 process are [H2O2] = 1.97 mM, light intensity = 90 W, pH = 3 and the removal rate is 72.3 %; the optimal treatment conditions for Fenton process are [H2O2] = 1.18 mM, [Fe2+] = 0.059 mM, light intensity = 90 W, pH = 3 and the removal rate is 85.4 %; the optimal treatment conditions for photo-Fenton process are [H2O2] = 1.97 mM, [Fe2+] = 0.059 mM, light intensity = 90 W, pH = 3 and the removal rate is 96.8 %. Hence, among the three processes, the effect of photo-Fenton process was the best in terms of both CTC and COD pollutants removal rate. Furthermore, for Fenton process and photo-Fenton process, equilibrium was achieved after 20 to 30 minutes of treatment, suggesting AOP to be a very effective treatment method.

碩士
國立雲林科技大學
環境與安全衛生工程系
107
Fenton and sunlight photo-Fenton photodegradation of aqueous Rhodamine B (Rh B) were carried out using zero-valent iron Fe(0) as a catalyst to investigate the effect of different dosing amounts of hydrogen peroxide (H2O2) and zero-valent iron on degradation. The experimental results showed that using Fenton completely degraded Rh B with an initial concentration of 20 mg/L at 2.0 mM H2O2 and 17.86 mM of Fe(0), however using the photo-Fenton method only required 0.5 mM of H2O2 and 8.92 mM of Fe(0) to completely decompose Rh B at the same initial contaminant concentration. Moreover, the removal efficiency of organic matter compared that using Fenton was a COD removal rate of only 36.36% for Rh B, and using photo Fenton reached 78.79%. This study highlights the utility of the photo Fenton method in the use of sunlight. Since the Fe(0) is fine-grained and has the feasibility of repeated use, this study used a linear estimation of the removal rate under each batch (reaction time of 20 minutes) then nine repeated experiments, and predicted at least 33 times to be reused at 50% of the residual pollutants as the endpoint. According to the optimized dose cost analysis, if Fenton did not recycle and use Fe(0) at a dose of 17.86 mM and a H2O2 of 2.0 mM, the dosing cost was 213.71 NT dollars/ton of wastewater, while photo Fenton added the dose only required a Fe(0) of 8.92 mM and a H2O2 of 0.5 mM, basing on zero-valent iron reused for at least 33 times, the cost of dosing calculated to be 8.81 NT dollars/ton of wastewater. To sum up, sunlight photo Fenton effectively and rapidly degraded the refractory pollutant Rh B in water and using Fe(0) as a reused catalyst, at the same complete degradation effect, photo Fenton greatly reduced the cost from dose.

碩士
國立成功大學
化學工程學系碩博士班
99
Hydroxyl radical is very reactive, underlying the chemistry of advanced oxidation processes (AOPs) for degrading organic compounds in water. Among various AOPs, Fenton’s reagent has been known to be an effective and simple oxidant. It is found that the Fenton reaction can be an efficiency enhanced in photo-electro-Fenton process since ferric may complex with certain target compounds or byproducts, especially those acting as ligands, produced by UVA light and current. The new design of our system came from the concept of promoting the ferric reduction rate, which can increase the amount of hydroxyl radicals. In this study investigated photo-electro-Fentonto oxidize 1 mM of 2,6-dimethylaniline and 1.6 mM pyridine. This investigation reveals that photo-electro-Fenton can completely degrade 1 mM of 2,6-dimethylaniline. However only 83.44 % of TOC removal can be eliminated after 240 min of reaction at of 200 mg L-1 of Fe2+, pHi=2, 1800 mg L-1 H2O2, CDc=23.19 A m-2. 94% pyridine degradation and 70% TOC can be removed after 240 min of the reaction in the presence of 50 mg L-1 Fe2+, pHi=2, 1600 mg L-1 H2O2, CDc=4.64 A m-2. In addition, we also calculated the observed reaction constant k1 and k2 with different condition of operation using pseudo-first-order reaction. Futhermore, the mechanism of 2,6-dimethylaniline and pyridine was proposed in this study. It is also found that 2,6-dimethylaniline can not completely be oxidized to carbon dioxide but transformed to some intermediates which have similar like of 2,6-dimethylaniline and No heterocyclic intermediate in the pyridine system.

碩士
國立中興大學
環境工程學系所
100
All of Advanced oxidation processes (AOPs) have the same characteristic, which can produce strong oxidation ability, non-specific hydroxyl radical (‧OH) to effectively decompose a variety of organic pollutants in the wastewater. This study investigates the removal and chemical oxygen demand (COD) of octylphenol polyethoxylates (Triton X-100, TX-100) surfactant by Fenton process, or combined UV light at various operating parameters in UV/H2O2, Fe2+/H2O2 and UV/Fe2+/H2O2 systems. Furthermore, the efficiencies of three oxidation processes were compared. The maximum removal rate for Triton X-100 wastewater with UV/H2O2, Fenton and photo-Fenton processes were 43%, 95% and 97% respectively. And COD removal rate were 4%, 44% and 50% respectively. The optimum operating conditions for photo-Fenton process in this study was as follows : UV light intensity = 90 W, pH = 3, [H2O2]/[Fe2+] molar ratio = 4.5 ([H2O2]/[Fe2+] = 1.155/0.257 mM, [H2O2]/[TX-100] molar ratio = 15) Under the same Fenton reagent ratio and dosage, the sequence of three processes was photo-Fenton > Fenton > UV/H2O2. The removal rate with photo-Fenton processes was 97% after 90 min of reaction, Fenton and UV/H2O2 were 69% and 10% respectively after 120 min of reaction. The results showed that the oxidation by UV/Fe2+/H2O2 was the strongest, and even greater than the arithmetic sum of the other two processes.

碩士
國立交通大學
工學院碩士在職專班永續環境科技組
98
In the semiconductor substrate process, stripping liquids use for washing unfinished surface. Ethylenediamine (C2H4N2) about 10% in the organic stripping liquids, is the main organic pollutant source in the wastewater of the industry. The decomposition by traditional acid process or physical oxidation and biological disposal are undesirable. This incomplete treatment of the wastewater will impact environment. The photo-degradation process i.e. a higher oxidative treatment, results in the rapid degradation of the target compound compared to other methods. It has been reported that hydroxyl radicals with great destruction power upon excitation of Fe (III) aqua complexes and UV irradiation were useful for the degradation and mineralization of complicated compound. Therefore, photochemical oxidation using Fenton’s reagent and UV irradiation has been considered as a promising technology for the treatment of organic stripping liquids, but higher running cost, and electrical energy demand. Biological treatment is still regarded for general common and economical way treatment of contaminants wastewater. The activate sludge process have demonstrated potentials to fundamentally advance the technology and practice of wastewater treatment. However, they have limitation in the degradation of recalcitrant substance such as the organic stripping liquids. The results show, 50 mg/L Ethylenediamine solution, under the conditions at pH 3.0, Fe2+ concentration of 267 mg/L, Fe2+/H2O2 0.1 to 10, the reaction time is 1 hour to photo-Fenton process in the decomposition of Ethylenediamine The average TOC removal after about 7%; before and after photo-Fenton reaction, the NH3-N, NO2- and NO3- concentration did not change significantly. In Fe2+/H2O2 is 0.75, the removal of 1% of the TOC produced by Ethylenediamine takes about 4.625 mg/L of H2O2 consumption. COD removal rate along with Fe2+/H2O2 ratio increases, in addition to H2O2 was 200mg/L, COD removal rate decreased, much of H2O2 showed possible competition effects added. And its average BOD5/COD ratio greater than 0.7, indicating photo-Fenton process can effectively enhance the biodegradability of Ethylenediamine.

碩士
大葉大學
環境工程學系碩士班
98
This study discusses the effects of ultrasound (US) irradiation on the decolorization of C.I. Reactive Red 2 (RR2) in UV/Fenton and UV/Fenton-like systems. The used oxidants were H2O2 and Na2S2O8; additionally, the metal ions were Fe2+ and Fe3+. The effects of oxidant concentration, metal ion dosage, wavelength of UV light, US irradiation and the addition of radical scavenger were determined in this work. The experimental data indicated that the concentration of oxidant had a threshold limit for the decolorization of RR2. However, the decolorization rate of RR2 increased with the metal ion dosage increasing. This work found that the decolorization rate fitted with the pseudo-first-order kinetics. The irradiation of UV light promoted the decolorization rate of RR2 in Fenton and Fenton-like systems; moreover, the decolorization rate of 254 nm irradiation was higher than that of 365 nm. Under 0.01 mM metal ion addition, the decolorization rate followed the order US/Fenton (0.0710 min-1) > Fenton (0.0503 min-1) > US/Na2S2O8/Fe2+ (0.0217 min-1) > Na2S2O8/Fe2+ (0.0192 min-1) > US/H2O2/Fe3+ (0.0070 min-1) > US/Na2S2O8/Fe3+ (0.0049 min-1) > H2O2/Fe3+ (0.0020 min-1) > Na2S2O8/Fe3+ (0.0005 min-1). This study showed that the irradiation of US accelerated the decolorization rate of RR2 in Fenton and Fenton-like systems. The addition of C2H5OH inhibited the decolorization rate of RR2 in UV/US/Fenton and UV/US/H2O2/Fe3+ systems; hence, this research suggested that the hydroxyl radicals were the main oxidation reagents. However, the addition of C2H5OH did not terminate the decolorization of RR2 in UV/US/Na2S2O8/Fe2+ and UV/US/Na2S2O8/Fe3+ systems; accordingly, the oxidation of HO2 and sulfate radicals could not be ignored in UV/Fenton-like systems.

博士
國立交通大學
環境工程系所
100
Carbofuran, a pesticide belong to the category of carbamate derivative, will contaminate surface and groundwater through leaching from applied site. Since carbofuran exhibits a special biorefractory character and require longer biodegradation time, its complete degradation in a shorter time could only be achieved by advanced oxidation processes. Therefore, photochemical oxidation i.e. photo-Fenton process has been considered as a promising technology for the degradation of carbofuran. The effects of irradiation time, carbofuran concentration, pH, H2O2 dosage rate and Fe3+ dosage on photo-Fenton treatment of carbofuran were evaluated in this study. The treatment efficiency was estimated based on the reductions of carbofuran concentration and dissolved organic carbon (DOC). The outcomes demonstrate that all the parameters had positive effect on carbofuran degradation except carbofuran concentration. With carbofuran concentration of 50 mg L-1, no significant improvement in the carbofuran and DOC removals was observed when the H2O2 dosage rate and Fe3+ dosage were increased beyond 4 mg L-1 min-1 and 35 mg L-1, respectively. Furthermore, the value of pH 3 was found to be the best suitable for carbofuran degradation and mineralization under the photo-Fenton process. At pH value of 3, carbofuran (50 mg L-1) was completely degraded within 30 min and 93% DOC removal was achieved after 120 min reaction under H2O2 dosage rate 4 mg L-1 min-1 and Fe3+ dosage 35 mg L-1. A two factor central composite design along with response surface methodology was employed to estimate the favorable H2O2 dosage rate (1-10 mg L-1 min-1) and Fe3+ dosage (1-100 mg L-1) in the photo-Fenton treatment of carbofuran and to develop the second-order polynomial equations in terms of carbofuran and DOC removals and BOD5/DOC ratio as responses with different reaction times. DOC removal is found to be highly related with H2O2 concentration in the system. Therefore, high loading of H2O2 dosage rate must be employed to achieve high carbofuran mineralization within a short reaction time. Based on the results of carbofuran removal and BOD5/DOC ratio, H2O2 dosage rate of 5.4 mg L-1 min-1 and Fe3+ dosage of 59 mg L-1 were found to be the favorable reagent dosages for carbofuran degradation. Carbofuran (100 mg L-1) was completely removed within 30 min reaction and 41% DOC removal was reached at these conditions. Moreover, the H2O2/Fe3+ ratio was found to be varied from 0.75 to 9.04 within 60 min reaction. Based on the results of Microtox® test and BOD5/COD ratio at the favorable reagent dosages, a reaction of 45 min was chosen as the appropriate time for coupling the photo-Fenton process with biological treatment. Under these conditions, 96% carbofuran removal was achieved, the toxicity unit (TU) measured with 15 min exposure was decreased to 10 and the biodegradability evaluated by BOD5/COD ratio was increased from 0 to 0.38. The reduction of TU and increase of biodegradability represented an easily biodegradable effluent. Moreover, average oxidation state and carbon oxidation state were increased from -0.03 to 0.42 and 1.82, respectively, which revealed the strong mineralization and generation of oxidized organic intermediates during the photo-Fenton treatment of carbofuran. Furthermore, five major carbofuran intermediates were identified, which indicate that C-O bond of the carbamate group and 3-C position of the furan ring were oxidized as a result of the photo-Fenton reaction. The results obtained in this study demonstrate that the photo-Fenton process is a promising pretreatment method before the application of biological treatment for carbofuran removal from contaminated water/wastewater.

碩士
淡江大學
水資源及環境工程學系
89
The type of iron salts is one of important operational variables in the photo-Fenton process. The ferric ions can be reduced to ferrous ion by UV photolysis. The ferrous ions react with hydrogen peroxide to occur the Fenton reaction. This study was to evaluate the decomposition and decolorization of a reactive dye by the Photo-Fenton process. The commercial available reactive dye, Blue 19, was employed to prepare the synthetic wastewater sample. The experimental variables studied include dosages of hydrogen peroxide and iron salts, and type of iron salts. All experiments were conducted by a batch photo reactor. Moreover, the sulfate ferrous and nitrate ferric were used iron salts. The residual color and dye was determined by the ADMI method and high performance liquid chromatograph (HPLC), respectively. The results show that the solubility of iron salts decreases with the increase of pH. The solubility of ferric increases in the presence of oxalate. The Fe(III)-oxalate is the predominant complex compound under acidic pH ranged from 4 to 6. Since the oxalate is a organic compound. It can compete hydorxyl radicals (OH·) with the dye and reduce the removal of color. The optimal oxidation time for the removal of color and dye was 5 min by the Ferrioxalate /H2O2/UV process. Due to the color-contained ferrous-dye complexes, the color resurgence was observed as the oxidation time more than 5 min. The color resurgence was significant at higher ferrous dosages. Furthermore, the color removal increases significantly with the increase of H2O2 dosage. The color resurgence was less at higher H2O2 dosage. In contrast, the color and dye was removed for reaction time only 1 min by the Fe2+/H2O2/UV process. The color resurgence does not occur during the reaction period. Comparing the removal of color and dye by these two processes, results indicate the Ferrioxalate/H2O2/UV process performs higher removal of dye and color than that by Fe2+/H2O2/UV process, in early reaction period. However, the Fe2+/H2O2/UV process has higher removal of color with a longer reaction time.

碩士
國立聯合大學
環境與安全衛生工程學系碩士班
101
Photo-Fenton process, especially using natural solar light as light source, has attracted great interest for the treatment of dye wastewater in recent years. However, the inductive mechanisms and effect of solar photo-enhancement involving reduction of ferric ion to ferrous ion on degradation of dye wastewater are still not clear nowadays. The possible inductive Fe(III) reduction i.e. Fe(II) regeneration mechanisms may include direct photoreduction, photodecarboxylation, photosensitization, and quinone-like cycle reduction. Therefore, the objective of this study is mainly to investigate the effect of various inductive Fe(III) reduction mechanisms involved in solar photo-Fenton (like) process for treatment of dye wastewater. Moreover, the ANOVA and ANN analysis were applied to examine the qualitative and quantitative effect of three main factor, namely, gH2O2/gCOD, [H2O2]0/[Fe3+]0, and reaction time, on the mineralization efficiency of dye wastewater. Three organic dyes wastewater with different structure and characteristics including Acid Orange 10 (AO10), Alizarin Violet 3B (AV), and Methylene Blue (MB) were investigated in this study. Results showed that the Fe3+ reduction pathways could be divided into three stages in solar photo-Fenton-like degradation of AO10 and MB wastewater. In the initial reaction stage (0-0.01 min), the direct photoreduction accounted for a 28-39% of Fe3+ reduction and the Fenton-like mechanism account for a 54-64% of Fe3+ reduction while Fe3+ reduction was only 4-6% through photosensitization. In the second reaction stage (1-10 min), because the intermediate - oxalic acid was generated, leading to the major Fe(III) reduction mechanism transferred to photodecarboxylation, which accounted for a 91-97% of Fe3+ reduction in this stage. In addition, the reduction rate of Fe(III) was more than tens of times and hundreds of times of direct photoreduction and Fenton-like reaction mechanism, respectively. In the third reaction stage (15 min later), H2O2 and the generated oxalic acid were decomposed gradually, resulting in the Fe3+ reduction through the photodecarboxylation and Fenton-like mechanisms were consequently reduced and the Fe3+ reduction would be majorly by way of direct photoreduction. On the other hand, because the molecular structure of AV has a quinone-like structure, the Fe3+ reduction was mainly through the pathway of quinone-like cycle reduction (48.6%) and photodecarboxylation (47%) in the initial reaction. Therefore, the direct photoreduction and Fenton-like Fe3+ reduction mechanisms only accounted for 1.73% and 1.93% of total Fe3+reduction, respectively. Photo-Fenton (like) process with the radiation of various light wave bands would affect the degradation efficiency of dye wastewater as well as the Fe3+ reduction mechanisms. It was found that because the Fe3+ reduction mechanisms relied primarily on the direct photoreduction and Fenton-like pathway in the initial degradation of AO10 and MB wastewater, the degradation efficiency of AO10 and MB wastewater was not noticeable with the irradiation of visible light band. On the other hand, more Fe2+ could be generated through the quinone-like cycle reduction pathway in AV wastewater so that the impact of irradiation of light wave band was less. In contrast, photo-Fenton (like) process with the radiation of UV light band showed much higher degradation efficiency for AO10 and MB, even AV wastewater since the photodecarboxylation accompanying with Fe3+ reduction was more effective. The use of the analysis of variance (ANOVA) and the connection weights of the artificial neural networks (ANN) allow to perform an analysis of the relative relevance of each factor with respect to others. Results showed that the quantitative saliency of three main factor (gH2O2/gCOD, [H2O2]0/[Fe3+]0, and reaction time) on the mineralization efficiency of dye wastewater were 43.63%, 10.91%, and 45.44% for AO10, respectively, 11.71%, 30.08%, and 58.20% for MB, respectively, and 25.16%, 20.71%, and 54.13% for AV, respectively. It can be concluded that the reaction time is the most significant factor affecting dye mineralization. The dosage of [H2O2]0/[Fe3+]0 have a greater impact weights in MB and AV while an increasing in dosage of gH2O2/gCOD is more beneficial for the mineralization of AO10. Based on the results obtained in this study, it was revealed that solar energy had a significant promotion effect on the Fenton like reaction mainly through various and incessant mechanism of reduction of Fe3+ ions and regeneration of Fe2+ ions, especially for dye wastewater. The use of ANOVA and ANN analysis provided meaningful information for controlling major process factors efficiently, leading to improve reaction efficiency in practical application. Keywords: solar photo-Fenton (like) process, dye wastewater, Fe3+ reduction mechanism, ANOVA, artificial neural network , direct photoreduction, photosensitization reduction, photodecarboxylation, quinone-like cycle reduction