Relevant bibliographies by topics / Hexavalent chromium reduction

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Academic literature on the topic 'Hexavalent chromium reduction'

Author: Grafiati
Published: 4 June 2021
Last updated: 8 February 2022

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Journal articles on the topic "Hexavalent chromium reduction"

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Kajitvichyanukul, Puangrat, and Chulaluck Changul. "PHOTOCATALYTIC REMOVAL OF TR I- AND HEXA-VALENT CHROMIUM IONS FROM CHROME-ELECTROPL ATING WASTEWATER." ASEAN Journal on Science and Technology for Development 22, no. 4 (November 11, 2017): 355. http://dx.doi.org/10.29037/ajstd.171.

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A novel technique based on photocatalysis was applied to eliminate chromium ions, a toxic hazardous environmental pollutant. The photoreduction of each species of chromium (total, hexavalent, and trivalent chromiums) from chrome-electroplating wastewater was investigated using a titanium dioxide suspension under irradiation by a low-pressure mercury lamp. The initial concentration of total chromium was 300 mg/l. The applied conditions were the direct photocatalytic reduction process at pH 3.65 and the indirect photocatalytic reduction with added hole scavengers at the same solution pH. Results from both processes were comparatively discussed. Result show that chromium was not efficiently removed by direct photoreduction. In contrast, with the adding of hole scavengers, which were formate ions, the photoreduction of chromium was very favorable. Both hexavalent and trivalent chromiums were efficiently removed. The photocatalytic mechanism is purposed in this study.
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Wang, Yi-Tin, and Hai Shen. "Bacterial reduction of hexavalent chromium." Journal of Industrial Microbiology 14, no. 2 (February 1995): 159–63. http://dx.doi.org/10.1007/bf01569898.

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Horitsu, Hiroyuki, Satoshi Futo, Yoshimi Miyazawa, Shusuke Ogai, and Keiichi Kawai. "Enzymatic Reduction of Hexavalent Chromium by Hexavalent Chromium TolerantPseudomonas ambiguaG-1." Agricultural and Biological Chemistry 51, no. 9 (September 1987): 2417–20. http://dx.doi.org/10.1080/00021369.1987.10868422.

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Patterson, J. W., E. Gasca, and Y. Wang. "Optimization for Reduction/Precipitation Treatment of Hexavalent Chromium." Water Science and Technology 29, no. 9 (May 1, 1994): 275–84. http://dx.doi.org/10.2166/wst.1994.0495.

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This paper describes wastewater treatment optimization studies performed on an industrial wastewater generated in Boston, Massachusetts, USA. The manufacturing plant generates hexavalent chromium [Cr(VI)] wastewater as a result of chromating brass, bronze and copper parts produced in the manufacturing operations. The facility utilizes a continuous flow treatment train, involving segregated Cr(VI) reduction with sodium metabisulfite (Na2S2O5) under acidic conditions, followed by combined wastestream two-stage pH adjustment, metals precipitation, and clarification before discharge to the municipal sewer. The objectives of the studies were to define and evaluate critical parameters, such as pH and oxidation reduction potential (ORP) for hexavalent and total chromium control and to perform treatability studies to optimize the performance of the wastewater treatment plant (WWTP). The treatability studies included Cr(VI) reduction versus Na2S2O5 dosage evaluations and corresponding chromium reduction kinetic studies, and trivalent chromium hydroxide precipitation. The Cr(VI) reduction experiments and chromic hydroxide precipitation studies were performed for three different wastewaters collected from within the manufacturing process; a high, typical, and dilute strength wastewater.
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Georgios, Samiotis, Lefteri Lefteris, Mavromatidou Charoula, Tsioptsias Costas, Trikilidou Eleni, Batsi Anna, and Amanatidou Elisavet. "Hexavalent Chromium Removal from Groundwater—A Low-Tech Approach." Environmental Sciences Proceedings 2, no. 1 (August 14, 2020): 25. http://dx.doi.org/10.3390/environsciproc2020002025.

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Chromium occurs in nature mainly in its trivalent or hexavalent form. Hexavalent chromium Cr(VI) is particularly toxic to humans, animals, and plants. The extensive pollution of groundwaters with Cr(VI) necessitates the complete understanding of natural chromium oxidation and reduction mechanisms, both for assessing the risk of hexavalent chromium formation and for the development of techniques for the reduction and removal of Cr(VI) from contaminated water bodies. In this work, the possibility of hexavalent chromium reduction by discarded or low-cost materials, which contain reducing compounds, is investigated regarding the creation of a compact, pump-and-treat filter for Cr(VI) removal from groundwater.
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Thacker, Urvashi, Rasesh Parikh, Yogesh Shouche, and Datta Madamwar. "Hexavalent chromium reduction by Providencia sp." Process Biochemistry 41, no. 6 (June 2006): 1332–37. http://dx.doi.org/10.1016/j.procbio.2006.01.006.

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Basu, Ankita, and Bidyut Saha. "Kinetic Studies on Hexavalent Chromium Reduction." American Journal of Analytical Chemistry 01, no. 01 (2010): 25–30. http://dx.doi.org/10.4236/ajac.2010.11003.

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Mystrioti, Christiana, Stefania Koursari, Anthimos Xenidis, and Nymphodora Papassiopi. "Hexavalent chromium reduction by gallic acid." Chemosphere 273 (June 2021): 129737. http://dx.doi.org/10.1016/j.chemosphere.2021.129737.

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HORITSU, Hiroyuki, Satoshi FUTO, Yoshimi MIYAZAWA, Shusuke OGAI, and Keiichi KAWAI. "Enzymatic reduction of hexavalent chromium by hexavalent chromium tolerant Pseudomonas ambigua G-1." Agricultural and Biological Chemistry 51, no. 9 (1987): 2417–20. http://dx.doi.org/10.1271/bbb1961.51.2417.

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Sedlak, David L., and Pamela G. Chan. "Reduction of hexavalent chromium by ferrous iron." Geochimica et Cosmochimica Acta 61, no. 11 (June 1997): 2185–92. http://dx.doi.org/10.1016/s0016-7037(97)00077-x.

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Dissertations / Theses on the topic "Hexavalent chromium reduction"

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Taylor, Orlando C. (Orlando Clearchus). "In-situ reduction of hexavalent chromium by electroremediation with ferrous iron." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10260.

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CORREIA, THIAGO OLIVEIRA FERREIRA. "SYNTHESIS OF NANOSTRUCTURED FE0-NI0/SIO2 PARTICLES FOR THE REDUCTION OF HEXAVALENT CHROMIUM TO TRIVALENT CHROMIUM." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2018. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=36037@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
No presente trabalho, foram abordadas duas formas alternativas de materiais para a redução do cromo hexavalente. Para um dos materiais foram sintetizadas nanopartículas de ferro metálico, níquel metálico e sílica como suporte, e o outro material visando menor custo e maior acessibilidade foi uma lã de aço comercial. Ambos têm como objetivo a diminuição ou remediação de cromo hexavalente através de soluções de dicromato de potássio em concentrações que visam simular contaminações geradas por diversas operações industriais. A função destes materiais é de atuar como um forte agente redutor, doando elétrons para reduzir o cromo hexavalente em cromo trivalente. As nanopartículas de ferro zero valente, níquel zero valente suportadas em sílica foram sintetizadas empregando sulfatos em uma técnica de redução com borohidreto de potássio em solução aquosa. As nanopartículas foram caracterizadas com o auxílio da técnica de difração de raio-X para determinar as fases presentes, e de microscopia eletrônica de varredura com espectroscopia por dispersão de energia, definindo a composição química elementar e a morfologia das superfícies, e ICP para quantificar a composição dos elementos ferro e níquel. Finalmente, foram realizados os testes de redução do cromo hexavalente em cromo trivalente através do Espectrofotômetro UV-VIS, sendo quantificada a concentração de cromo hexavalente presente na solução através da técnica colorimétrica com o reagente altamente seletivo, o 1,5-difenilcarbazida (DFC). As nanopartículas e a lã de aço demonstraram eficiência na redução do cromo hexavalente em concentrações de 8,32 ppm (K2Cr2O7 80 Mmol/L), 6,241 (K2Cr2O7 60 Mmol/L) e 4,161 ppm (K2Cr2O7 40 Mmol/L) com tempos inferiores a 5 minutos. Contudo, as nanopartículas de Fe0-Ni0 suportadas em SiO2 reduziram o cromo hexavalente com uma quantidade em massa de Fe0 aproximadamente 110 vezes menor em relação a lã de aço, considerando que este é constituído unicamente por ferro metálico. Credita-se esta efetividade à maior área superficial por unidade de massa das partículas nanoestruturadas.
In the present work, two alternative forms were approached using different materials. For one of the materials, nanoparticles of metallic iron, metallic nickel and silica as support were synthesized, and the other material aiming at lower cost and greater accessibility will be steel wool. Both have the objective of reducing or remediation of hexavalent chromium through solutions of potassium dichromate in concentrations that aim to simulate contaminations generated by various industrial operations. The function of these materials is to act as a strong reducing agent by donating electrons to reduce the hexavalent chromium to trivalent chromium. The nanoparticles of zero-valent Iron, zero-valent nickel supported on silica was synthesized using sulfates in a reduction technique with potassium borohydride in aqueous solution. The nanoparticles were characterized with the help of the XRD technique, from the diffraction pattern generated and quantifying the present phases, and SEM / EDS, defining elemental chemical composition and surface morphology and ICP to quantify the elemental composition. Finally, the tests of reduction of the hexavalent chromium in trivalent chromium through the UV-VIS spectrophotometer were carried out, and the concentration of hexavalent Chromium present in the solution was quantified through the Colorimetric technique with the highly selective reagent, 1,5-diphenylcarbazide (DFC). Nanoparticles and steel wool showed efficiency in the reduction of hexavalent chromium at concentrations of 8,32 ppm (K2Cr2O7 80 Mmol/L), 6,241 (K2Cr2O7 60 Mmol/L) e 4,161 ppm (K2Cr2O7 40 Mmol/L) with times less than 5 minutes. However, as Fe0-Ni0 nanoparticles supported in SiO2, they reduced the hexavalent content of a quantity of steel mass in relation to steel wool, considering that it consists only of metallic iron. The effectiveness in the most superficial part by the mass unit of the nanostructured particles is credited.
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Ng, Nai Hong 1979. "Investigation of the role of electron mediators and siderophores on the concurrect biodegradation of naphthalene and reduction of hexavalent chromium." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82623.

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The concurrent biodegradation of polycyclic aromatic hydrocarbons (PAHs) and transformation of heavy metals by redox reactions has been demonstrated by several studies. The mechanisms and reactions that result in heavy metal transformation in such systems is, however, poorly understood. This study explored the role of metabolic intermediates, metabolic end-products, and microbial chelators generated by a PAH-degrading microorganism, Pseudomonas putida ATCC 17484, in reducing or transforming Cr(VI). This study investigates the role of 1,2-naphthoquinone to serve as potential redox mediators in the reduction of Cr(VI) to Cr(III). Laboratory experiments were conducted to evaluate the extent of Cr(VI) reduction in the presence of various concentrations of the naphthalene biodegradation by-product 1,2-naphthoquinone, and the metabolic intermediate 1,2-dihydroxynaphthalene. Rapid, but limited reduction of Cr(VI) was observed in the presence of 1,2-dihydroxynaphthalene. The effect of siderophore Desferrioxamine B (DFB), a common chelator produced by the soil microorganisms, on the biodegradation of naphthalene was also investigated. Synthesized DFB was added directly into the test systems, and resulted in instantaneous binding to chromium (VI). The chelated complex remained stable for a period of 4 days even when subjected to acidic conditions.
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Franco, Debora Vilela. "Tratamento redutivo de solo e agua subterranea contaminados com cromo hexavalente." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249653.

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Orientador: Wilson de Figueiredo Jardim
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
Made available in DSpace on 2018-08-13T18:50:44Z (GMT). No. of bitstreams: 1 Franco_DeboraVilela_D.pdf: 6112505 bytes, checksum: 9ffd8531fa2a0322c7b7d08e90de70fa (MD5) Previous issue date: 2008
Resumo: A redução química do cromo hexavalente, Cr(VI), presente em solo e água subterrânea contaminados, foi investigada empregando-se diferentes agentes redutores (batelada e semi-batelada) para avaliar a extensão da redução do Cr(VI) e da imobilização (precipitação) do cromo trivalente, Cr(III). O estudo comparativo envolvendo o uso de diferentes agentes redutores evidenciou que as espécies Fe(II) e FZVcol (nanopartículas estabilizadas com carboximetilcelulose) apresentaram os resultados mais promissores para a remoção do Cr(VI), visto que houve uma redução quantitativa desta espécie com sua concomitante imobilização. A aplicação do Fe(II) e FZVcol nas razões molares 1[Cr(VI)]:20[Fe(II)] e 1[Cr(VI)]:4[FZVcol] resultou na conversão redox superior a 98% e na imobilização das frações de Cr(VI) lábil e trocável. Foi verificado para o Fe(II), que o aumento da velocidade do fluxo volumétrico (G) resulta na diminuição do número de volume de poro para o tratamento do solo e da quantidade de Cr(VI) residual. O estudo hidrodinâmico teórico da coluna recheada com solo (meio poroso) permitiu mensurar o grau de dispersão do redutor na coluna frente ao modelo pistonado de escoamento em função de G mediante o cálculo do coeficiente de dispersão mássica volumétrico (kDV), o qual foi calculado a partir da modelagem da curva de saturação experimental. Foi verificado em todos os casos que a cinética do processo redox Cr(VI)/Cr(III) segue uma lei empírica de velocidade de pseudo-primeira ordem. A complexidade cinética do processo redox foi evidenciada pela dependência da constante de velocidade global de pseudo-primeira ordem (k*) com o tempo de reação, G e a concentração inicial do redutor. Um modelo cinético fenomenológico foi proposto para se obter uma expressão representativa de k* nas diferentes situações experimentais investigadas, bem como nos casos limites previstos. Um esquema reacional global foi proposto para representar os diferentes processos elementares envolvendo as espécies Cr(VI) e Cr(III) na matriz porosa (solo/água subterrânea). Um ensaio de tratamento em escala piloto foi realizado in situ tendo-se como balizadora as condições experimentais mais promissoras obtidas nos estudos realizados em escala laboratorial
Abstract: Chemical reduction of the hexavalent chromium, Cr(VI), present in contaminated soil and groundwater was investigated using several different reductants (batch and semi-batch) in order to evaluate the extension of Cr(VI) reduction and the immobilization (precipitation) of trivalent chromium, Cr(III). A comparative study concerning the use of different reductants revealed that Fe(II) and ZVIcol (nanoparticles stabilized with carboximethylcellulose) present the most promising findings for the Cr(VI) removal, since it was found that a quantitative reduction of this specie is accompanied by its immobilization. Application of Fe(II) and ZVIcol using the 1[Cr(VI)]:20[Fe(II)] and 1[Cr(VI)]:4[ZVIcol] molar ratios resulted in a redox conversion degree higher than 98% and in the immobilization of the labile and the exchangeable Cr(VI) fractions. It was verified for Fe(II) that increasing the volumetric flow rate (G) both the pore volume necessary for the redox treatment and the residual Cr(VI) decrease. The theoretical hydrodynamic study concerning the packed column reactor containing soil (porous medium) permitted to evaluate the reductant dispersion degree inside the column in relation to the plug-flow model as functions of G by measuring the volumetric mass dispersion coefficient (kVD), which was calculated from simulation of the experimental saturation curve. In all cases, it was found the kinetics of the Cr(VI)/Cr(III) redox process follows a pseudo-first order rate law. The complexicity concerning the kinetic process was evidenced by the dependence of the overall pseudo-first order kinetic rate constant (k*) on reaction time, G and the initial concentration of the reductant. A phenomenological kinetic model was proposed in order to obtain a relation capable to represent k* for the different experimental conditions investigated, as well for the possible limit cases. An overall reaction scheme was proposed in order to describe the different elementary processes concerning the Cr(VI) and Cr(III) species, which take place inside the porous soil matrix (soil/groundwater). A pilot scale test was carried out in situ taking into account the best experimental scenario obtained in laboratory.
Doutorado
Quimica Analitica
Doutor em Ciencias Quimicas
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Kabeche, Tanina. "Procédé de traitement in situ des sites pollués par réduction chimique à l'aide de micro et nanoparticules de fer zérovalent." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0034/document.

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Dans cette thèse, nous avons déterminé les mécanismes qui régissent l'efficacité des particules de fer zérovalent (ZVI) dans la dépollution des sols et des eaux souterraines. Dans les milieux contaminés par des polluants accepteurs d'électrons, le ZVI est injecté in situ sous forme de suspensions de particules micro et/ou nanométriques. La première étude a porté sur la caractérisation de poudres industrielles et de particules synthétisées au laboratoire à partir de thé vert. Afin de comparer la réactivité de l'ensemble des particules, un test en milieu fermé a été mis en oeuvre avec une solution de nitrate. Ce test a permis de différencier les particules en mettant en évidence des mécanismes réactionnels et des cinétiques de réduction qui dépendent du type de poudre utilisé. La seconde étude a porté sur la dégradation du chrome hexavalent (dans une matrice sol et eau) en combinant le ZVI à du thiosulfate de sodium. Les résultats ont été probants et ont mené au dimensionnement d'un pilote sur un site de Soléo Services. Enfin, deux cas de remédiation de sites pollués aux solvants chlorés ont été étudiés. Des expériences de laboratoire ont été menées pour expliquer l'impact des conditions opératoires sur l'efficacité du traitement
This thesis aims at a better understanding of mechanisms governing the efficiency of zerovalent iron (ZVI) particles in soil and groundwater remediation. In these processes ZVI is injected in situ as micro and/or nanoparticles slurry in areas contaminated by electron acceptor pollutants. At first, we characterized industrial powders and particles synthetized with green tea in the laboratory. In order to compare the reactivity of all the particles, a batch test has been carried out with nitrate solution. Differences in pathways and kinetic reduction have been exhibited. Secondly, we combined ZVI with sodium thiosulfate to investigate hexavalent chromium degradation (soil and water matrices). The results are conclusive and were used to design a pilot on a Soléo Services site.Finally, remediation cases of sites contaminated by chlorinated solvents have been investigated. Lab experiments have been run to explain the influence of operating conditions on the treatment efficacy
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Mončeková, Miroslava. "Úloha síranu železnatého jako regulátoru tuhnutí a redukčního činidla portlandského slínku." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2016. http://www.nusl.cz/ntk/nusl-256551.

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In 2003, the European Community Obligation (directive 2003/5C/EC) regulates a maximal value of soluble hexavalent chromium to 0.0002 % (per weight of dry cement). This limitation leads to modifications of the regular Portland cement by using of suitable reduction agents. Therefore, the possibilities of chromium reduction become a very actual topic. The primary goal of this work is a basic research of the ferrous sulphate influence on hexavalent chromium reduction and also its influence on Portland clinker hydration process. The reduction ability was determined by UV/VIS method. The mechanism and ferrous sulphate influence on Portland clinker hydration process was observed by isothermal calorimetry and mechanical strength tests. XRD method, SEM-EDS analysis and Raman microscopy were used for identification of formed hydration products. Study of hydration mechanism occurring in this system was focused on the divergence observations from the regular Portland cement hydration. Pore solution analysis provided significant information about chromium behavior during the hydration process (substitution and releasing). Chromium incorporation into structure of hydration products during the reduction process was also studied in the pure tricalciumaluminate system with targeted Cr6+ content. This work suggests the possible substitution of the trivalent and hexavalent chromium into structure of monosulphate (AFm) phase.
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Xu, Xiangrong. "Reductive detoxification of hexavalent chromium and degradation of methyl tertiary butyl ether and phthalate esters." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B31636196.

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Xu, Xiangrong, and 徐向榮. "Reductive detoxification of hexavalent chromium and degradation of methyl tertiary butyl ether and phthalate esters." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B31636196.

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Moura, Alex Anderson de Oliveira. "Influência de campo eletromagnético aplicado no biotratamento de efluente de cromo hexavalente." Universidade Federal de Uberlândia, 2012. https://repositorio.ufu.br/handle/123456789/15187.

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Fundação de Amparo a Pesquisa do Estado de Minas Gerais
This work was to study the influence of the magnetic field on the reduction of hexavalent chromium, removal of COD and total chromium, addition of cell growth in batch (batch reactor), using a mixed culture from located in a tanning city of Franca-SP (AMCOA). The influence of static magnetic field generated by a device that produces an electric current through a conductor, producing a magnetic field around the conductor, like a magnet. This equipment produces a magnetic field pulsed square wave of constant intensity and frequency. In the first step of adjusting the mixed cultures of chromium VI obtained a promising response. Thereafter, a preliminary test was performed to analyze the behavior of the influence of the magnetic field in the reduction of chromium VI and diameter of the reactor, obtaining 71% reduction of chromium VI with a larger diameter, without the presence of magnetic field has seen a reduction of 53%, with an initial concentration of 100 mg/l of chromium and a time of 4 hours of process. In other stages of the project, performing the tests with different frequencies of the magnetic field (1,2,5 and 10 Hz) and doing an analysis related to cell death of micro-organisms, showed that for frequencies of 10 Hz, there was cell death presents some cultures, which was confirmed in a lower frequency. The results were satisfactory when used in a magnetic field frequency of 5 Hz, maximal reduction of chromium VI reducing the time about 4 hours of processing, better removal of COD and total chromium using a volume of 500 ml and concentration of 100 mg/l initial chromium. Checking the influence of different frequency magnetic field, the initial effluent volumes (300 and 1000 ml) and initial concentration of chromium VI (50, 150 and 200 mg/l). The higher the initial concentration the lower the chromium reduction of chromium VI, larger volumes and a reduction of chromium VI and removal of COD and total chromium is not as significant as the use of smaller volumes.
Neste trabalho foi realizado o estudo da influência do campo magnético sobre a redução de cromo hexavalente, remoção de cromo total e DQO, além do crescimento celular em modo descontínuo (reator batelada), utilizando-se de uma cultura mista proveniente do curtume AMCOA localizado na cidade de Franca-SP. Foi avaliada a influência de campo eletromagnético estático gerado por um equipamento que produz uma corrente elétrica, passando por um condutor, produzindo um campo magnético ao redor do condutor, como se fosse um ímã. Este equipamento produz um campo magnético pulsante com onda quadrática de intensidade e frequência constantes. Na primeira etapa de adaptação das culturas mistas ao cromo VI obteve-se uma resposta promissora. Posteriormente, foi realizado um teste preliminar para analisar o comportamento da influência do campo magnético na redução de cromo VI e diâmetro de reator, obtendo 71% de redução de cromo VI com um maior diâmetro, sem a presença de campo magnético obteve uma redução de 53%, com uma concentração inicial de 100 mg/L de cromo e com um tempo de 4 horas de processo. Nas outras etapas do projeto, realizando os testes com diferentes frequências de campo magnético (1, 2, 5 e 10 Hz) e fazendo uma análise relacionada à morte celular dos micro-organismos, mostrou-se que para frequências de 10 Hz, havia morte celular de algumas culturas presentes, o que não foi verificado em uma frequência menor. Os resultados foram satisfatórios quando se utiliza uma frequência de campo magnético de 5 Hz, com máxima redução de cromo VI reduzindo o tempo em torno de 4 horas de processo, com melhor remoção de cromo total e DQO, utilizando um volume de 500 mL e concentração de 100 mg/L de cromo inicial. Verificando a influência de diferentes frequências de campo magnético, volumes iniciais de efluente (300 e 1000 mL) e concentrações iniciais de cromo VI (50, 150 e 200 mg/L). Quanto maior a concentração inicial de cromo menor foi a redução de cromo VI, e em volumes de efluentes maiores a redução de cromo VI e remoção de cromo total e DQO não foram tão significativas quanto em se aplicar volumes menores.
Mestre em Engenharia Química
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"Hexavalent Chromium Removal Using Ultraviolet Photocatalytic Reactor." Master's thesis, 2013. http://hdl.handle.net/2286/R.I.20986.

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abstract: Hexavalant chromium (Cr(VI)) poses an emerging concern in drinking water treatment with stricter regulations on the horizon. Photocatalytic reduction of Cr(VI) was investigated as an engineering scale option to remove hexavalent chromium from drinking or industrial waters via a UV/titanium dioxide (TiO2) process. Using an integrated UV lamp/ceramic membrane system to recirculate TiO2, both hexavalent and total chromium levels were reduced through photocatalytic processes without additional chemicals. Cr(VI) removal increased as a function of higher energy input and TiO2 dosage, achieving above 90% removal for a 1g/L dose of TiO2. Surface analysis of effluent TiO2 confirmed the presence of chromium species.
Dissertation/Thesis
M.S. Engineering 2013
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Books on the topic "Hexavalent chromium reduction"

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J, McGuire Michael, AWWA Research Foundation, and Glendale (Calif.). Water and Power., eds. Hexavalent chromium removal using anion exchange and reduction with coagulation and filtration. Denver, Colo: Awwa Research Foundation, 2007.

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J, McGuire Michael, AWWA Research Foundation, and Glendale (Calif.). Water and Power., eds. Hexavalent chromium removal using anion exchange and reduction with coagulation and filtration. Denver, Colorado: AWWA Research Foundation, 2007.

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Book chapters on the topic "Hexavalent chromium reduction"

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López–Vásquez, A., N. Ramirez, and R. López–Vásquez. "In Situ Photocatalytic Reduction for Contaminated Soil with Hexavalent Chromium by Titanium Dioxide." In Transactions on Engineering Technologies, 107–19. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-9115-1_9.

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Deote, Shweta V., A. B. Ingle, Swapnil Magar, and Ruchika Jain. "Reduction of Hexavalent Chromium Using Microbial Remediation: A Case Study of Pauni and Taka Chromite Mines, Central India." In Innovations in Sustainable Mining, 183–201. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-73796-2_11.

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Kaliwon, Babby Freskayani Izyani. "A Study on Artificial Hexavalent Chromium Removal by Using Zero Valent Iron Reactor and Sand Filter in Electrochemical Reduction Process." In InCIEC 2014, 1003–9. Singapore: Springer Singapore, 2015. http://dx.doi.org/10.1007/978-981-287-290-6_87.

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"Magnetic Ferro-photo Gels for Synergistic Reduction of Hexavalent Chromium in Wastewater." In Composites and Nanocomposites, 85–90. Apple Academic Press, 2013. http://dx.doi.org/10.1201/b14994-11.

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Focardi, Silvia, Milva Pepi, and Silvano E. "Microbial Reduction of Hexavalent Chromium as a Mechanism of Detoxification and Possible Bioremediation Applications." In Biodegradation - Life of Science. InTech, 2013. http://dx.doi.org/10.5772/56365.

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Shih, Y., C. Chen, K. Hsia, and C. Dong. "Optimization of hexavalent chromium (Cr(VI)) reduction by granulated nano zero-valent iron (nZVI)." In Environmental Engineering and Computer Application, 139–43. CRC Press, 2015. http://dx.doi.org/10.1201/b18565-29.

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Conference papers on the topic "Hexavalent chromium reduction"

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Paik, N., and Y. Shin. "379. Reduction of Hexavalent Chromium Collected on PVC Filters by Time." In AIHce 1997 - Taking Responsibility...Building Tomorrow's Profession Papers. AIHA, 1999. http://dx.doi.org/10.3320/1.2765521.

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Quadros, BC. "911 Elimination, reduction, and control of hexavalent chromium respiratory exposure: a brazilian case." In 32nd Triennial Congress of the International Commission on Occupational Health (ICOH), Dublin, Ireland, 29th April to 4th May 2018. BMJ Publishing Group Ltd, 2018. http://dx.doi.org/10.1136/oemed-2018-icohabstracts.569.

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"Photo-catalytic reduction of hexavalent chromium (Cr(VI)) under visible light with Bi-Zn co-doped TiO2." In 8th International conference on Research in Engineering, Science and Technology. Acavent, 2018. http://dx.doi.org/10.33422/8rest.2018.11.50.

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Nabil, S., T. M. Zewail, and N. K. Amin. "The Performance of A Batch Rotating Fixed Bed of Scrap Bearing Iron Spheres in Hexavalent Chromium Reduction." In 2015 International Conference on Environmental Science and Sustainable Development (ICESSD 2015). WORLD SCIENTIFIC, 2016. http://dx.doi.org/10.1142/9789814723039_0048.

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Reports on the topic "Hexavalent chromium reduction"

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Johnson, Thomas M. Chromium isotopes as indicators of hexavalent chromium reduction. Office of Scientific and Technical Information (OSTI), March 2012. http://dx.doi.org/10.2172/1036716.

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Bansal, S. Electrochemical reduction of hexavalent chromium in ground water. Office of Scientific and Technical Information (OSTI), December 1994. http://dx.doi.org/10.2172/96634.

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Hedgecock, Nancy S. Hexavalent Chromium Reduction Pretreatment Process Evaluation, Randolph AFB, Texas. Fort Belvoir, VA: Defense Technical Information Center, September 1990. http://dx.doi.org/10.21236/ada228805.

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