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Diaz, Mendoza Alvaro. "Conception of a fibrous composite material for the retention of heavy metals." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI125.
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La contamination par les métaux lourds est un problème actuel qui affecte les écosystèmes et leurs organismes constitutifs. Ce problème a été reconnu dans le monde entier comme l'un des plus grands défis de notre époque. Depuis le milieu du siècle dernier, les innovations dans le domaine de la science des matériaux ont permis de mettre au point de nouvelles méthodes pour faire face à ce risque, avec des techniques telles que la précipitation chimique ou la flottation. Toutefois, il reste encore beaucoup à faire dans ce domaine. En outre, des recherches récentes ont exploré comment combiner des biomolécules telles que les protéines avec des matériaux tels que les polymères pour créer des solutions plus actives. Ce travail de thèse vise à créer un prototype de matériau adsorbant hybride capable de capturer spécifiquement les ions métalliques divalents Ni(II), Cd(II) et Pb(II) grâce à la présence d'une métalloprotéine synthétique dans sa structure. Pour atteindre cet objectif, le travail de thèse se concentre sur le développement d'une métalloprotéine synthétique capable de capturer spécifiquement les trois ions métalliques cibles, de la conception in silico à sa synthèse in vivo. D'autre part, le support de matériau est traité avec la technique d'électrofilage qui consiste en un matériau membranaire fibreux, étant optimisé pour accueillir la métalloprotéine synthétique dans sa structure. En outre, une méthode permettant d'intégrer la métalloprotéine dans le support polymère est recherchée. Ceci est réalisé au moyen d'une voie de greffage à travers des nanoparticules de silice modifiées en surface. À la fin, l'intégration des deux composants crée le prototype attendu de matériau biosorbant synthétique. Ce matériau a été caractérisé afin d'évaluer sa capacité à adsorber les trois ions métalliques d'intérêt, ce qui permet de dégager certaines tendances des perspectives futures de développement pour créer des matériaux plus efficaces pour l'industrieHeavy metal contamination is a current problem which affects the ecosystems and their constituent organisms. This problem has been worldwide recognized as one of the biggest challenges of our time. Since the middle of the last century, innovations in the material science field have developed new methods to confront this risk, with techniques such as chemical precipitation or flotation. However, there is still significant room for improvement in this line. Furthermore, recent research has explored how to combine biomolecules such as proteins with materials like polymers to create more active solutions. This thesis work seeks to create a prototype hybrid biosorbent material capable to capture specifically the divalent metal ions Ni(II), Cd(II) and Pb(II) thanks to the presence of a synthetic metalloprotein in its structure. To address this objective, the thesis work focuses on the development of a synthetic metalloprotein capable to specifically capture the three target metal ions, from the in silico conception to its in vivo synthesis. On the other hand, the biosorbent material support is processed with the electrospinning technique that consists of a fibrous membrane material, being optimized to host the synthetic metalloprotein in its structure. Additionally, a method to integrate the metalloprotein into the polymeric support is researched. This is achieved by means of a grafting route through surface modified silica nanoparticles. At the end, the integration of both components creates the expected prototype synthetic biosorbent material. This material has been characterized to evaluate its capacity to adsorb the three metal ions of interest, providing some trends of the future perspectives for further development to create more efficient materials for the industry
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Harper, Harvey H. "Fate of heavy metals from highway runoff in stormwater management systems." Diss., University of Central Florida, 1985. http://digital.library.ucf.edu/cdm/ref/collection/RTD/id/75101.
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University of Central Florida College of Engineering ThesisThe movement and fate of heavy metal inputs (Cd, Zn, Mn, Cu, Al, Fe, Pb, Ni and Cr) from highway runoff were investigated in a three-year study on 1.3 hectare retention facility near the Maitland Interchange on Interstate 4, north of Orlando, Florida. Physical characteristics of the retention pond and surrounding watershed were defined and field instrumentation was installed. Stormwater samples were collected over a one-year period, representing a wide range of intensities and antecedent dry periods. Stormwater characteristics were compared with average retention pond water quality to determine removal efficiencies for heavy metals within the pond. A total of 138 core samples were collected in the pond over a three-year period to investigate the horizontal and vertical migrations of heavy metals within the pond. Sediment core samples were also carried through a series of sequential extraction procedures to examine the type of chemical associations and stability of each metal in the sediments. An apparatus was built which allowed sediments to be incubated under various conditions of redox potential and pH to investigate the effects of changes in sediment conditions on the stability of metal-sediment associations. Five groundwater monitoring wells were also installed to monitor metal movement and accumulations under stormwater management systems. Heavy metal inputs from highway runoff were found to be predominantly particulate in nature, with dissolved fractions for most metals of only 25 percent. Upon entering the retention pond, most metal species settled into the sediments within 60-90 m of the inlet. Removal efficiencies for metals after entering the pond averaged 70-90 percent for particulate species and about 50 percent for dissolved species. Sediment concentrations of heavy metals were highest near the surface, with rapidly decreasing concentrations with increasing depth. Metal-sediment associations appear to be very strong for most metals, with the vast majority of metal inputs into the pond over the eight-year life still remaining in the top 10 cm. Concentrations of all heavy metals measured were higher in groundwaters beneath the pond that in the pond water; but for most metals, the increases only extended to depths of 1-3 m beneath the pond. In general, metal concentrations beneath swale areas were significantly higher than concentrations beneath the retention pond. Due to slow groundwater movement in the area, the effects of increased metal concentrations are very localized. Evidence was presented to suggest that mobilization of metals into groundwaters could substantially increase with time if maintenance procedures are not conducted.
Ph.D.
Doctorate
Civil Engineering and Environmental Sciences
Engineering
Environmental Engineering
390 p.
xix, 390 leaves, bound : ill. ; 28 cm.
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Almutairi, Fahad M. "Feasibility of polymer enhanced ultrafiltration (PEUF) for heavy metals retention under competitive conditions." Thesis, Swansea University, 2009. https://cronfa.swan.ac.uk/Record/cronfa42647.
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Heavy metals are valuable resources for the modern world; however, they are potentially hazardous. Contamination exists in aqueous waste streams of many industries, such as metal plating facilities, mining operations, and tanneries. The soils surrounding many military and industrial sites are also contaminated and pose a risk of metals groundwater and surface water contamination. Some metals associated with these activities are cadmium, chromium, lead, and mercury. Heavy metals are not biodegradable and tend to accumulate in living organisms, causing various diseases and disorders. However, heavy metals have a high commercial value if they can be recovered in pure form. Polymer enhanced ultrafiltration (PEUF) was investigated because it offers the potential to selectively recover metals rapidly from solutions containing low concentrations. However, the major drawback (complex solutions containing other chelators and competitors) of these processes have not been investigated in detail and a fundamental understanding of these processes in real systems is required to truly assess and exploit their potential. The aim of this project was to investigate the performance of PEUF for metal ions filtration in batch mode and continuous feeding using metals, individual and in mixtures, metal binding chelator and competitor. A variety of feed compositions were used, and metal ions retention profiles were determined. The competition from other chelators or competitors for metal ions was investigated in the presence of PEI. The binding mechanisms of metal ions were explored and the ability of the Langmuir isotherm model to describe these systems using a batch and continuous feed was determined. Based on the principal of mass balance and Langmuir adsorption isotherms, a mathematical model describing the continuous feed of PEUF was developed. Ultrafiltration experiments were carried out in the stirred dead-end ultrafiltration cell and cross flow ultrafiltration systems. The metals investigated were: Cu2+, Zn2+, Ni2+, Cr6+, Co2+ and Cd2+. The results showed that adding PEI to metal ion solutions significantly increases the retention of the metal ions in the solution to greater than 90% at its best. However, the addition of the polymer significantly reduces the flux of the process (by approximately 50%) for equivalent solution conditions. Membrane surface charge is also a factor which is critical to the process performance. In general, the highest retention of metal ions occurred when the membrane had its highest negative charge. The results of the binding studies showed that the Langmuir isotherm offers a better description of the binding process than the Freundlich isotherm. The work reported here showed that competition for ions from other chelators or competitors is possible and change the performance compared to ideal simple systems. It also showed some potential advantages of this approach by changing capacity and selectivity of the separation based on PEUF processes. Under competitive conditions with chelators and competitors, maximum capacities of metal ions bind to PEI using Langmuir isotherm in continuous feed of PEUF were greater than those obtained from batch system, they were similar for Cu2+-PEI complex in single and mixed metals solutions of both systems. The model developed in this project showed good predictions of the experimental results with minor exception in the case of strongly competitive situations.
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Potter, Hugh 1967. "A study of the retention of heavy metals by amorphous iron-aluminium oxides and kaolinite /." Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36683.
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Amorphous iron-aluminium oxides are ubiquitous in the environment and control the availability of heavy metals (Pb, Cu). Oxide physicochemical properties are affected by the proportion of Fe and Al, the Fe/Al ratio. Five amorphous oxides containing Fe and/or Al were synthesised: "Fe" (only Fe); "3FeAl" (3 moles Fe per mole Al, Fe/Al = 3); "FeAl" (Fe/Al = 1); "Fe3Al" (Fe/Al = 0.3); "Al" (only Al). Kaolinite clay was also investigated along with kaolinite to which Fe-Al oxides had been added.The effect of Fe/Al ratio on these physicochemical properties was studied: (1) Specific surface area---EGME retention; (2) pH-dependent cation and anion exchange capacity---Ca(NO3)2 saturation; (3) Particle size density---sieving, pipette methods; (4) Surface charge density---potentiometric titrations.
The Fe/Al ratio influenced the specific surface area: Fe and 3FeAl had significantly greater surface areas than Fe3Al and Al; FeAl exhibited the maximum surface area. The cation exchange capacity increased rapidly above pH 5, with Fe > 3FeAl > Al > Fe3Al > FeAl at pH 6 to 7. Surface charge density of low Fe/Al oxides was more sensitive to pH changes implying ≡AlOH surface hydroxyl groups are more easily protonated and de-protonated than ≡FeOH species. An open (porous) structure of loosely linked small particles was proposed with SO42- anions forming bridges between Al3+ and Fe3+ ions during oxide precipitation while inhibiting extensive crystal growth.
Pb and Cu retention was measured using 24 hour batch suspension tests with varying pH and contaminant concentrations (0.5 to 25 mmol/L). Higher Fe/Al ratio oxides retained more Cu and Pb at all pH values. Cu retention (0.5 to 5 mmol/L) and Pb retention (all concentrations) followed Fe > 3FeA > FeAl > Fe3Al > Al but at 25 mmol Cu/L, only Fe accumulated more Cu. However, low Fe/Al ratio oxides preferentially sorbed Cu over Pb from multi-contaminant solutions. Adsorption rather than bulk precipitation was the dominant accumulation mechanism. Geochemical modelling suggested surface precipitation occurred at higher contaminant concentrations.
Adding oxides to kaolinite significantly increased the clay's specific surface area, surface charge density and contaminant retention capacity; higher Fe/Al ratio oxide-amended clays retained more Pb and Cu.
Amorphous Fe-Al oxides substantially enhance heavy metal accumulation by soils with higher Fe/Al ratio oxides being particularly effective.
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Potter, Hugh. "A study of the retention of heavy metals by amorphous iron-aluminium oxides and kaolinite." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0029/NQ64646.pdf.
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Nehrenheim, Emma. "Metal retention from leachate using Industrial Waste Products." Licentiate thesis, Västerås : Department of Public Technology, Mälardalen University, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-197.
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Karapanagiotis, Nicolas Konstantine. "Heavy metal retention by the organic fraction of sewage sludge." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342264.
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Laallam, Gitte. "Transport and retention of heavy metals in contaminated soil and groundwater : A case study from Pukeberg glassworks in Småland, Sweden." Thesis, Stockholms universitet, Institutionen för naturgeografi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-141651.
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As much as 80 000 sites, including landfills from glass production industries, are estimated to be contaminated in Sweden. One of these landfills is located near the glassworks factory of Pukeberg, in the municipality of Nybro, Southeast Sweden. It has been found to be severely contaminated with heavy metals, which have toxic effects to humans and biota. The aim of this study is to investigate hydrologic properties at Pukeberg, including groundwater velocities and their potential (spatial) heterogeneity that would affect the transport of metals. Metal concentrations in soil, pore water and groundwater were measured to investigate such metal transport and retention at the site. Slug tests were conducted at the site to determine local discharges and water velocities. For comparison, total groundwater flows through the landfill were estimated by considering water balances of the upstream catchment. Results showed a much higher groundwater flow through the landfill at Pukeberg when estimated from water balance constraints of the upstream catchment, compared to when up-scaled from local measurements of hydraulic conductivities and gradients within the landfill. This points to the existence of aquifer heterogeneity, including preferential flow paths and low-flow zones. Depending on flow path, transport velocities of heavy metals could therefore differ considerably. With a pH of 7 in pore water, and relatively low DOC (dissolved organic carbon) concentrations, environmental conditions were found likely to favour a strong retention for most of the metals investigated. This conclusion is supported by our estimates of Kd (the soil-water partitioning coefficient), derived from the in-situ ratio between soil concentrations and pore water concentrations at the landfill. These estimates were consistently higher than previously reported laboratory results from leaching tests, as well as guideline values from the Swedish EPA. For instance, Kd for Pb and As was found to be 50600 l/kg and 16400 l/kg, respectively. Thus, for most metals, a limited transport downstream could be expected. Indications of high aquifer heterogeneity within the limited area investigated in this study however give rise to uncertainties, for instance regarding the representativeness of the taken samples. Possible future analyses of extended sampling schemes could decrease these uncertainties.
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Syrovetnik, Kristina. "Long-term metal retention processes in a peat bog : Field studies, data and modelling." Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-460.
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Lander, Mark S. "Evaluation of selected heavy metal concentrations in soils of an urban stormwater retention basin." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0002831.
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Phadungchewit, Yuwaree. "The role of pH and soil buffer capacity in heavy metal retention in clay soils /." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74563.
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The concept of soil buffer capacity was used in this study to investigate the capacity of soil to attenuate heavy metals when acid is involved in the soil system. The buffer capacity of soil in this study was found to depend mainly on carbonate content and cation exchange capacity (C.E.C.) of soils. The magnitude of buffer capacity followed the order: illite $>$ montmorillonite $>$ natural clay soil $ gg$ kaolinite.The study of heavy metal retention in soils was performed both by soil suspension test and soil column test. The results showed that as soils received increasing amounts of acid, high amounts of heavy metals (particularly Pb and Cu) could still be retained if the soils had a high enough buffer capacity to resist a change in pH such that it will not drop to $ Cu > Zn > Cd.$ The order changed to $Pb > Cd > Zn > Cu$ when soils were at low soil solution pH. Relative mobility of heavy metals found from the soil column test followed the order $Pb < Cu < Zn leq Cd.$
The relation of soil buffer capacity and heavy metal retention and movement in the clay soils found from this study revealed that the soil buffer capacity was a parameter that can be used in the prediction and prevention of heavy metal migration in soil. The soil buffer capacity is recommended as a parameter that should be included in the determination of soil properties particularly for the purpose of land application and disposal of wastes with leachates that could contain heavy metals. (Abstract shortened by UMI.)
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Clement, Corinne. "Etude de coulis hydrauliques pour la retention des cations polluants pb, cd, hg, sr, cs." Paris, ENMP, 1988. http://www.theses.fr/1988ENMP0091.
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PINTO, Tatiana de Oliveira. "Potencialidades do vermicomposto, de seu res?duo s?lido (da extra??o de subst?ncias h?micas), do biochar e de humina para o uso na remedia??o de solo contaminado com c?dmio." Universidade Federal Rural do Rio de Janeiro, 2016. https://tede.ufrrj.br/jspui/handle/jspui/1525.
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Cadmium is a heavy metal and it offers high risks to human health and it can affect ecosystem functioning at trace levels due to high toxicity, persistence time, which transcends decades and the fact that its bioavailability not diminish the long term. Rice (Oryza sativa L.) has the ability to incorporate large amounts of Cd2+ in their tissues and, therefore, today is the cereal that further incorporates this metal in the human diet by ingestion, causing serious health problems like the known disease as "Itai-Itai", whose main symptoms severe pain in bones and frequent fractures. For this reason rice plants were used in this study in combination with natural materials to assess the effects of these Cd2+. Natural materials such derived from organic matter is currently being used in the remediation of soils and effluents, but studies on the risks of its use today are scarce and often controversial. The use of humified organic matter like vermicompost and its derivatives is a sustainable alternative for the remediation of soils and sewage contaminated by heavy metals due to their chemical composition environmentally non-aggressive, low production cost and possible application in various crops. The aim of this study was to investigate the characteristics of biochar, vermicompost (VC), its solid fraction (RVC) and humin for use in the remediation of soil contaminated with Cd2+. For this was performed characterization of the interactions between the metal and the material through Freundlich and Langmuir adsorption isotherms, spectroscopic techniques CP MAS 13C-NMR and FTIR was also evaluated the ability of each material to provide Cd2+ to plants rice, by determining the root and leaf development parameters and Cd2+ content in plant tissues and the substrate. The surface morphology of the materials was performed using scanning electron microscopy (SEM). This study demonstrates that biochar used and humin are not effective materials for use in remediation. The biochar, although showing a high retention of Cd2+ allowed the bio availability of Cd2+ increasing the accumulation in tissues of rice plants. VC and RVC resulted materials with high Cd2+ retention capacity with a low availability of the metal. Specifically, the RVC can be an effective material for remediation purposes. We warn the risks of use the materials studied for soil remediation purposes contaminated with Cd2+ and propose the use of a new natural source material for phytoremediation purposes.
O C?dmio constitui um metal pesado que oferece altos riscos ? sa?de humana e que pode afetar o funcionamento do ecossistema em n?veis residuais devido ? sua alta toxicidade, seu tempo de persist?ncia, que excede d?cadas e ao fato de sua biodisponibilidade n?o diminuir a longo prazo. O arroz (Oryza sativa L.) possui a capacidade de incorporar quantidades importantes de Cd2+ em seus tecidos e, por esta raz?o, ? hoje o cereal que mais incorpora este metal na dieta humana por ingest?o, ocasionando s?rios problemas de sa?de como a doen?a conhecida como ?Itai-Itai?, que tem como principais sintomas fortes dores nos ossos e frequentes fraturas. Por esta raz?o plantas de arroz foram utilizadas neste estudo em associa??o com os materiais naturais para avalia??o dos efeitos do Cd2+ nestas. Materiais como os derivados da mat?ria org?nica vem sendo utilizados atualmente na remedia??o de solos e efluentes, por?m estudos sobre os riscos de seu uso s?o hoje escassos e muitas vezes controversos. A utiliza??o de mat?ria org?nica humificada, como Vermicomposto e seus derivados ? uma alternativa sustent?vel na remedia??o de solos e efluentes contaminados por metais pesados, devido ? sua composi??o qu?mica ambientalmente n?o agressiva, baixo custo de produ??o, e poss?vel aplica??o em diversas culturas vegetais. O objetivo deste estudo foi investigar as caracter?sticas do biochar, vermicomposto (VC), sua fra??o s?lida (RVC) e humina para serem usados na remedia??o de solos contaminados com Cd2+. Para tal foi realizada a carateriza??o das intera??es entre o metal e os materiais, atrav?s de isotermas de adsor??o de Freundlich e Langmuir, t?cnicas espectrosc?picas CP MAS 13C-RMN e FTIR, foi tamb?m avaliada a capacidade de cada material para biodisponibilizar o Cd2+ para plantas de arroz, atrav?s da determina??o de par?metros de desenvolvimento radicular e foliar e dos conte?dos de Cd2+ nos tecidos das plantas e no substrato. A morfologia da superf?cie dos materiais foi avaliada mediante microscopia eletr?nica de varredura (MEV). Este estudo demonstra que o biochar utilizado e a humina n?o s?o materiais eficientes para serem utilizados na remedia??o. O biochar, embora apresentando uma elevada reten??o de Cd2+ permitiu a biodisponibiliza??o do Cd2+ aumentando o ac?mulo nos tecidos das plantas de arroz. O VC e RVC resultaram materiais com elevada capacidade de reten??o de Cd2+ com uma baixa disponibiliza??o do metal. Especificamente o RVC pode constituir um material eficiente para fins de remedia??o. Adverte-se sobres os riscos no uso dos materiais estudados para fins de remedia??o de solos contaminados com Cd2+ e prop?em-se a utiliza??o deste novo material para fins de fitorremedia??o.
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Williams, Emily Rose. "The Effects of Depth and Hydrological Connectivity on Heavy Metal Loading in Riparian Zones." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-185245.
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The area between a stream and land is known as a riparian zone. These zones are highly dynamic whichcarry and accumulate heavy metals and environmental contaminants. Discrete Riparian Input Zones(DRIPs) are a subset of such zones that carry concentrated amounts of water into streams at discrete points.These are more active in their ability to channel water than riparian zones. These areas are important sincethey may retain or release metals and thereby affect the stream chemistry. To test if DRIPs accumulatemetals, 7 DRIPs and 4 Non-DRIPs were sampled along the C5 stream in the Krycklan Catchment. Soilsamples were taken from the surface down to 0.5 m depth at 0.1 m increments and were analysed for totalmercury, metals and loss on ignition. Three metals (vanadin, iron and zinc) were identified as having significant differences in concentration between DRIP and Non-DRIPS. Vanadin and Fe had significantlyhigher concentrations in Non-DRIPs, whereas iron had higher concentrations in DRIPs. Mercury,cadmium, iron, and loss on ignition (LOI) were found to decrease as depth increased, whilst Al was foundto increase with depth. Finally many elements are inter-related, but those with the strongest correlation areLOI and mercury, and iron and cadmium, both r > 0.85. LOI and mercury are strongly related as mercurybinds strongly to organic matter. The relationship of Fe and Cd is likely due to the Fe-oxide and Cdrelationship.
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Rothhardt, Steffi [Verfasser], Reinhard [Akademischer Betreuer] Gaupp, and Gerd [Akademischer Betreuer] Gleixner. "Influence of the white-rot fungus Schizophyllum commune on organically coated sand grains and their heavy metal retention / Steffi Rothhardt. Gutachter: Reinhard Gaupp ; Gerd Gleixner." Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2013. http://d-nb.info/1033670243/34.
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Bitencourt, Dioni Glei Bonini. "Dinâmica de acidificação e de liberação de metais na solução do solo de perfis de solos construídos na área de mineração de carvão de Candiota, RS." Universidade Federal de Pelotas, 2014. http://repositorio.ufpel.edu.br:8080/handle/prefix/3050.
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O carvão mineral e rochas associadas podem conter pirita, que ao entrar em contato com ar ou água sofre oxidação, produzindo ácido sulfúrico. Essa acidez acelera dissolução dos minerais do solo e aumenta a concentração de metais pesados na solução do solo, criando a drenagem ácida da mina que contamina as águas superficiais e subsuperficiais. Este estudo teve o objetivo de investigar o efeito da drenagem ácida nas propriedades químicas e na retenção da solução do solo construído numa área de mineração de carvão em Candiota, RS. Foram abertas trincheiras e coletadas amostras deformadas e indeformadas, em quatro profundidades (0-10; 40-50; 100-110; 190-200 cm), bem como instalados lisímetros de sucção e sensores de umidade, em perfis de solos construídos de diferentes idades e morfologia (sem terra vegetal: MII-T1 – 28 anos; com terra vegetal: MIV-T1 – 18 anos, MIV-T2 – 17 anos, MVII-T3 – 10 anos, MIV-T4 – 4 anos). Nas amostras deformadas foram realizadas análises físicas e químicas básicas (granulometria, pH (em água, em CaCl2), índice SMP, cátions trocáveis, acidez potencial e carbono orgânico), metais extraídos pelo método US-EPA3050, o potencial de acidificação (PA) e de neutralização (PN) pelo método do peróxido de hidrogênio, bem como a mineralogia, analisada por difratometria de raios X na forma de pó na amostra total. Para a coleta de solução do solo a campo foram instalados lisímetros de sucção (ecoTech, Bonn, Germany) e o monitoramento da umidade do solo foi feito com sensores de umidade (Watermark). A obtenção da solução do solo em laboratório foi feita pelo método do extrato da pasta saturada. Os metais e os cátions básicos das soluções do solo obtidas pelos dois métodos foram analisadas por ICP-OES e o Si e o S determinados por espectroscopia UVvisível e os resultados comparados por testes não paramétricos e em diagramas de estabilidade mineral. Foram obtidas curvas de retenção de solução do solo por câmara de Richards e pelo WP-4 e calculada a capacidade de água disponível em função do potencial osmótico. Concluiu-se que (a) todas camadas de estéril dos solos construídos possuem potencial de acidificação e que as camadas de terra vegetal e argila (malhas IV e VII) apresentaram potencial líquido positivo (não geradoras de acidez), indicando estarem livres de contaminação por sulfetos; (b) ambos os métodos de extração de solução do solo se mostraram equivalentes em termos de concentração de íons extraídos, conforme teste não paramétrico de Mann-Whitney; porém os diagramas de estabilidade mineral mostraram comportamento discrepante em função da maior atividade do Al na solução extraída com a pasta saturada em laboratório, mais diluída; (c) a solução do solo, por ambos métodos, confirmam a formação de drenagem ácida em profundidade, mesmo nas áreas com cobertura de terra vegetal ou argila (malhas IV e VII), indicando que essas camadas não são suficientes para conter ou minimizar o processo de geração de drenagem ácida; (d) na solução do solo foram encontrados valores acima do permitido para consumo humano para vários elementos (S, Cu, Zn, Fe, Mn, Cd, Cr, Ni, Pb, Se e As), como resultado do processo ativo de sulfurização, contrastando com a extração pelo método USEPA 3050, que indica somente valores acima para As e Se; (e) os estéreis de mineração dos solos construídos retém solução do solo com maior energia em relação às camadas superficiais (terra vegetal e argila) em função do caráter da porosidade dos estéreis, oriundo de processos litogênicos (diagênese), que aliada ao elevado potencial osmótico, reduz a quantidade de água disponível as plantas e (f) o monitoramento da variação da umidade do solo nos perfis dos solos construídos mostrou que as camadas de terra vegetal e de argila, em função da menor capacidade de retenção de água, mesmo quando saturadas, apresentaram menores níveis de umidade do solo ao longo do tempo do que as camadas mais profundas, compostas pelos estéreis de mineração.
The coal and associated rocks may contain pyrite, which undergoes oxidation, when in contact with air or water producing sulfuric acid. This acidity accelerates the dissolution of minerals from the soil and increase the concentration of heavy metals in the soil solution, creating the acid mine drainage which contaminates surface and subsurface waters. This study aimed to investigate the effect of acid mine drainage on the chemical properties and retention of the soil solution in constructed soil in coal mining area in Candiota, RS. Pits were opened and disturbed and undisturbed samples were collected at four depths (0-10, 40-50, 100-110, 190-200 cm) and suction lysimeters and humidity sensors were installed in soil constructed soil profiles of different ages and morphology (without topsoil: MII-T1 - 28 years; with topsoil: MIV-T1 - 18 years, MIV-T2 – 17 years, MVII-T3 - 10 years, MIV-T4 - 4 years). In the disturbed samples basic physical and chemical analysis were performed (particle size, pH (in water, CaCl2), SMP index, exchangeable cations, potential acidity and organic carbon), as well as metals extracted by the US-EPA3050 method, acidification (AP) and neutralization potential (PN) by the hydrogen peroxide method, and mineralogy, analyzed by X-ray diffraction in powder (total sample). In the field, suction lysimeters (Ecotech, Bonn, Germany), to collect soil solution, and moisture sensors (Watermark), to monitor the moisture, were installed. Soil solution were also extracted in the laboratory, by the saturated paste extract method. Metals and basic cations in soil solutions obtained by the two methods were analyzed by ICP-OES and Si and S determined by UV-visible spectroscopy and the results compared by nonparametric tests and mineral stability diagrams. Soil solution retention curves were determined with Richards chambers and by WP-4, and the available water capacity taking into account the osmotic potential. It was concluded that (a) all layers of mine overburden materials showed acidification potential while top soil and clay layers (MIV and MVII) had a positive net potential (non-acid generation), indicating the they were free from sulfides contamination; (b) both methods of extraction of soil solution showed to be equivalent in terms of concentration of extracted ions as analyzed by non-parametric Mann-Whitney test; but the mineral stability diagrams showed different behavior due to the higher activity of Al in solution extracted with saturated paste in the laboratory, more diluted; (c) the soil solution, by both methods, confirm the formation of acid drainage in depth, even areas covered by topsoil or clay layers (MIV MVII), indicating that these layers are not sufficient to contain or minimize the generation of acid mine drainage; (d) in soil solution values above the allowed for human consumption for various elements (S, Cu, Zn, Fe, Mn, Cd, Cr, Ni, Pb, Se and As) as a result of the active process of desulfurization were found, contrasting with the metals extracted by the USEPA 3050 method, that indicates that values above the allowed only to As and Se; (e) the overburden materials retain soil solution with higher energy than the topsoil and clay layers due to the character of their porosity, originated by lithogenic processes (diagenesis), which allied to the high osmotic potential, reduces the amount of plant available water and (f) the monitoring of the soil moisture in the constructed soil profiles showed that the topsoil and clay layers, due to the lower water holding capacity, even when saturated, showed lower levels of soil moisture over time than the deeper layers, composed by mine overburden.
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David, Telse. "Studying the contribution of urban areas to fine sediment and associated element contents in a river bed." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-113554.
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Urban wet weather discharge impairs the receiving water and sediment quality. Among other factors, particulate matter plays a role. It increases the suspended sediment load of the receiving water and may thus enhance the clogging of the bed sediment which serves as an important river habitat. This thesis investigates how much urban areas may contribute to the fine sediment and associated element load which is retarded by the bed sediment. It is based on an extensive field study. The study area was the Bode River, a mid-sized stream in Central Germany. About 10 km upstream of the river mouth, the sampling campaign took place close to Staßfurt, a town of 20’000. During the sampling campaign, the intrusion of fine sediment into the bed sediment was captured by sediment traps. Furthermore three possible sources of this fine sediment were sampled. Within the Town of Staßfurt, we sampled urban wet weather discharge at three sites to capture urban areas. As second source naturally occurring fine sediment was considered. Therefore we took sediment cores upstream of the Town of Staßfurt. As third source, the impact of the upstream catchment was captured by taking suspended sediment samples. For all sample types, particle-bound element contents were determined to establish element patterns of the receptor and the source sites. The rationale thereby is that the element pattern at the receptor sites results from the element patterns of the sources. Consequently the contribution of the sources can be calculated by mixing models. In the study area, particulate matter from urban areas is distinct from river borne fine sediment due to elevated copper, zinc, nitrogen and phosphorus contents. We conducted an in-depth analysis of this element pattern by a cluster analysis. It revealed that the particle-bound element pattern is source specific whereby nitrogen, phosphorus and carbon are related to sewage and behave differently than most metals such as copper which mainly originate from surface runoff. The degree to which element patterns agree from site to site is limited by the variability encountered within sample sets from individual sites. Thereby the variability of the element pattern depends on the complexity of the catchment. The contribution of urban areas to fine sediment and associated elements which were captured by sediment traps was calculated by a mixing model. Based on this mixing model, about 10% of the fine sediment originate from urban areas. Thereby the impact of the Town of Staßfurt could not be detected leading to the conclusion that upstream urban areas contribute most. Because of the elevated content of e.g. copper and zinc, urban areas contribute up to 40% and thus disproportionally high to particle-associated copper and zinc load. The source apportionment of the fine sediment is little influenced by the elements considered in the mixing model. Different element patterns showed that the median contribution of urban areas ranges from 0 – 20%. This lies within the interquartile range of the initial mixing model. Another result of the measurement campaign ist that sediment traps over-estimated the anthropogenic impact because they did not resemble the surrounding bed sediment. When they were exposed, they were completely free from fine sediment and hence served as sink of suspended sediment. During the sampling campaign, one source was not directly taken into account. It was possible, though, to delineate this source by nonnegative matrix factorization. Within the Town of Staßfurt, a soda ash production site discharges into the Bode River. The nonnegative matrix factorization uncovered that the soda ash production site is a major source of particulate matter and contributes up to 30% of the fine sediment captured by the traps downstream of the Town of Staßfurt. This source dilutes most element contents as it mainly consists of carbonates. This was revealed by studying the element binding according to the BCR extraction scheme. This thesis shows that urban areas may be a major source of particulate matter and especially associated elements retarded by the bed sediment. It shows that the element contents form a viable pattern to calculate how much urban areas contribute to fine sediment by mixing models. The thesis further shows that nonnegative matrix factorization is a viable tool to delineate such a distinct source as soda ash production siteMisch- und Regenwasserentlastungen beeinträchtigen die Qualität von Vorflutgewässern. Unter anderem gelangt Feinsediment während Entlastungsereignissen in Vorflutgewässer. Dieses erhöht die Fracht an suspendiertem Sediment und verstärkt die Kolmatierung der Gewässersohle. Damit ist das hyporheische Interstitial, das ein wichtiges Fließgewässerhabitat ist, vom Eintrag von Feinsediment betroffen. Diese Arbeit untersucht, wie sehr urbane Flächen zur Feinsedimentfracht und zur Fracht von partikulär gebundenen Elementen beitragen können, die im Bettsediment zurückgehalten werden. Sie beruht auf einer umfangreichen Messkampagne. Das Untersuchungsgebiet dafür war die Bode, ein mittelgroßer Fluss in Mitteldeutschland. Etwa 10 km flussaufwärts der Mündung fand die Messkampagne nahe der Kleinstadt Staßfurt statt. Im Rahmen dieser Messkampagne haben wir den Eintrag von Feinsediment in das Bettsediment durch Sedimentkörbe erfasst. Drei Quellen dieses Feinsediments haben wir berücksichtigt. In Staßfurt wurden eine Regen- und zwei Mischwassereinleitungen beprobt, um urbane Flächen zu erfassen. Als zweite Quelle wurde natürlich vorkommendes Feinsediment berücksichtigt. Dafür haben wir Sedimentkerne flussaufwärts von Staßfurt genommen. Als dritte Quelle haben wir das stromaufwärts liegende Einzugsgebiet erfasst, indem wir das suspendierte Sediment beprobt haben. Für alle Proben wurde der Elementgehalt bestimmt, um das Elementmuster des Feinsediments, das ins Bettsediment eingetragen wurde, und der Quellen zu ermitteln. Der Grund für diese Messstrategie war, dass das Elementmuster des Feinsediments in den Körben aus den Elementmustern der Quellen, Regen- bzw. Mischwassereinleitungen, natürlich vorkommendes Feinsediment und suspendiertes Sediment aus dem Einzugsgebiet, resultieren sollte. Damit ist es möglich, den Beitrag über Mischungsmodelle zu berechnen. Im Untersuchungsgebiet unterscheidet sich das Feinsediment, das von urbanen Flächen stammt, von dem flussbürtigen Feinsediment aufgrund erhöhter Kupfer-, Zink-, Stickstoff- und Phosphorgehalte. Wir haben das Elementmuster der urbanen Flächen mit einer Clusteranalyse genauer untersucht. Dies ergab, dass das partikulär gebundene Elementmuster quellenspezifisch ist, wobei sich Stickstoff, Phosphor und Kohlenstoff Abwasser zuordnen lassen, während die meisten Metalle wie Kupfer und Zink hauptsächlich aus dem Oberflächenabfluss stammen. Das Maß, zu dem die Muster von Messpunkt zu Messpunkt übereinstimmen, wird durch die Variabilität beschränkt, die die Proben eines Messpunktes aufweisen. Diese Variabilität hängt dabei von der Komplexität des Einzugsgebiets ab. Über eine Mischungsrechnung konnten wir berechnen, wie viel urbane Flächen zur Fracht von Feinsediment und daran gebundenen Elementen in den Sedimentkörben beitrugen. Im Untersuchungsgebiet stammen etwa 10 % des Feinsediments, das durch die Sedimentkörbe aufgefangen wurde, von urbanen Flächen. Der Beitrag der Stadt Staßfurt konnte dabei aber nicht von dem Beitrag weiter flussaufwärts gelegener urbaner Gebiete getrennt werden. Daraus folgt, dass weiter stromaufwärts liegende Gebiete mehr beitragen als Staßfurt. Wegen des erhöhten Gehalts an z.B. Kupfer und Zink tragen urbane Flächen ca. 40 % und damit überproportional hoch zur partikulär gebundenen Kupfer- und Zinkfracht bei. Für die Berechung des Quellenbeitrags zum Feinsediment spielt es keine große Rolle, welche Elemente in der Mischungsrechnung berücksichtigt werden. Verschiedene Elementmuster ergeben, dass der Medianbeitrag urbaner Flächen zwischen 0 und 20 % liegt. Dies entspricht dem Interquartilsabstand der ursprünglichen Mischungsrechnung. Ein weiteres Resultat der Untersuchungen ist, dass die Sedimentkörbe den anthropogenen Einfluss überschätzten, weil sie das umgebende Bettsediment nicht exakt abbildeten und als Falle funktionierten. Innerhalb Staßfurts gibt es ein Sodawerk, das seine Produktionsabwässer in die Bode einleitet. Während der Messkampagne wurde diese Quelle nicht direkt erfasst. Es war trotzdem möglich, diese Quelle durch nicht-negative Matrix-Faktorisierung zu identifizieren. Die nicht-negative Matrix-Faktorisierung ergab, dass das Abwasser des Sodawerks eine Hauptquelle des Feinsediments der Bode ist. Bis zu 30 % des Feinsediments in den Sedimentkörben flussabwärts von Staßfurt lassen sich dem Sodawerk zuordnen. Dieses Feinsediment besteht hauptsächlich aus Karbonaten und verdünnt die meisten Elementgehalte. Dies wurde deutlich, indem die Elementbindungen nach dem BCR Extraktionsschema untersucht wurden. Diese Arbeit zeigt die Relevanz, die urbane Flächen als Quelle von Feinsediment und daran gebundener Elementfracht haben, die ins Interstitial eingetragen werden. Sie zeigt, dass die Elementgehalte ein Muster bilden, mit dem es möglich ist, über eine Mischungsrechnung zu klären, wie viel urbane Flächen zum Feinsediment beitragen. Die Arbeit zeigt ferner, dass nicht-negative Matrix-Faktorisierung ermöglicht, eine so charakteristische Quelle wie ein Sodawerk zu identifizieren
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CANUTO, Morgana Fabíola Cunha Silva. "Estudo da cinética de biossorção do íon Cd2+ pela levedura Saccharomyces cerevisiae." Universidade Federal de Campina Grande, 2007. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1816.
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MORGANA FABÍOLA CUNHA SILVA CANUTO - DISSERTAÇÃO PPGEQ 2007..pdf: 11947934 bytes, checksum: 493b8b41a0683172ddfe091d9f129285 (MD5)Made available in DSpace on 2018-09-26T14:23:41Z (GMT). No. of bitstreams: 1 MORGANA FABÍOLA CUNHA SILVA CANUTO - DISSERTAÇÃO PPGEQ 2007..pdf: 11947934 bytes, checksum: 493b8b41a0683172ddfe091d9f129285 (MD5) Previous issue date: 2007-05-31
CNPq
O aumento das atividades industriais intensificou os problemas com poluição ambiental por metais pesados e principalmente por cádmio, por ser dentre os metais pesados, muito utilizados em vários processos industriais e por ser extremamente tóxico em baixas concentrações, além de causar sérios problemas de saúde. A biossorção, vem se colocando como uma alternativa potencialmente atrativa para uma grande variedade de efluentes industriais. Este processo vem adquirindo suma importância por utilizar biossorventes de baixo custo operacional, além de que os mesmos podem apresentar alta seletividade e taxa de remoção. Dentre os biossorventes utilizados para retenção dos metais pesados em efluentes industriais destacam-se os fungos, a exemplo da Saccharomyces cerevisiae que pode ser utilizado neste processo por possuir grande capacidade de retirar metais pesados dos efluentes industriais. Uma outra vantagem é que se trata de um resíduo facilmente obtido em grandes quantidades como subproduto de processos industriais, tendo em vista que o Brasil é o maior produtor mundial de álcool etílico via processo fermentativo, utilizando-se deste microrganismo como agente da fermentação. Experimentos da cinética de biossorção do íon cádmio utilizando a Saccharomyces cerevisiae foram realizados, sendo os mesmos conduzidos em tanques agitados. Os modelos empíricos cinéticos utilizados foram o modelo empírico de dois parâmetros e o pseudo-segunda ordem, os mesmos apresentaram boa reprodutibilidade para o parâmetro qe (capacidade adsortiva), como também se obteve bom ajuste nas curvas cinéticas, exceto quando se trabalhou com concentração elevada e na maior temperatura. A técnica de planejamento experimental foi utilizada para avaliar os efeitos das variáveis concentração inicial do íon metálico e temperatura sobre os parâmetros cinéticos. A concentração inicial do íon metálico estudado foi a variável que apresentou influência significativa quando comparado com o efeito da temperatura nas condições estudadas. Os melhores resultados de capacidade de adsorção foram obtidos com o aumento da concentração do metal.
The increase in the industrial activities has intensified the problems of environmental pollution by heavy metals and mainly due to cadmium. Cadmium metal is the one which is mostly used in various industrial processes and is extremely toxic in low concentrations, besides causing serious health problems. The biosorption process is becoming a potentially attractive alternative for a great variety of industrial effluents. This process is important as it utilizes biosorbents of low operational cost, higher selectivity and high metal removal rates. Amongst the biosorbents used for heavy metal retention from industrial effluents, the fungi are distinguished. For example, the Saccharomyces cerevisiae can be used for such purpose as it has higher capacity of metal removal from industrial effluents. Another advantage is that, it is a residue which is easily obtained in big amounts as by-product of industrial processes. Brazil is world-wide big producer of ethanol and utilizes this microorganism as fermentation agent. Kinetic experiments for cadmium ion biosorption using Saccharomyces cerevisiae in agitated recipient were carried out. The empirical kinetic models used were the empiric model of two parameters and the pseudo-secondorder. These models presented a good reproduction for the parameter qe (adsorption capacity), as well as showed a good fit for experimental kinetic curves, except when high concentration and temperature were used. To evaluate the effect of initial concentration of the metal ion and temperature variables on the kinetic parameters the experimental design methodology was used. The initial metal ion concentration was the variable that had significant influence when compared with the effect of the temperature, in the conditions studied. The best adsorption capacity results were obtained when the metal ion concentration was increased.
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Oltmanns, Jan. "Biosensors for heavy metals." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/22854.
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Heavy metals from natural and man-made sources can be a great threat to human and animal life. As small inorganic ions they are challenging to detect, usually requiring expensive and complicated machinery. Several heavy metals can accumulate in the human body, leading to long term toxic effects on the nervous system. Many bacteria have developed strategies to survive in heavy metal rich environments. One of these strategies is a bacterial operon containing genes for detoxification mechanisms controlled by a promoter and a regulatory protein. In this work some of these promoter-protein pairs, Pars-ArsR, PcopA-CueR, PmerTPAD-MerR and PzntA-ZntR from Escherichia coli have been employed in the design and construction of a set of biosensors aimed at the detection of heavy metals in drinking water. Biosensors usually employ biological recognition elements, transducing the signal from these to produce an output that can be integrated into electronic circuitry. The sensors presented in this work focus on reducing complexity and on providing a controlled sensor reaction. The arsenic biosensor ‘AsGard’ is based on the Pars-ArsR pair and functions by making the dissociation of an ArsR-mCherry fusion protein from its binding site in the Pars promoter visible. In the cell, ArsR dissociates from Pars upon binding of trivalent arsenic ions. Immobilising the relevant part of the Pars sequence on a solid plastic support allows for the mobilisation of previously bound ArsR-mCherry proteins in the presence of arsenic to become the sensor output. The AsGard sensor detects arsenic within minutes in a concentration range overlapping with the arsenic thresholds for drinking water as set by the World Health Organisation. Additional prototype sensors are presented bringing a reporter gene under the control of the aforementioned promoters. These sensors have been tested in vivo and in vitro in a cell free transcription translation system and partially detect metal concentrations close to relevant ranges. The Pars based sensor is tuneable in vitro by modifying the ratio of the supplied regulatory protein ArsR and is able to detect arsenic well within the relevant range. Spinach2, a fluorescent RNA aptamer, may make future designs independent from translation, drastically reducing complexity of cell free biosensors based on cis-trans transcriptional regulation.
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Sörme, Louise. "Urban heavy metals stocks and flows /." Linköping : Univ. : Vatten i natur och samhälle, Institutionen för tema [distributör], 2003. http://www.bibl.liu.se/liupubl/disp/disp2003/arts270s.pdf.
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Beckett, C. L. "Heavy metals in Severn Estuary ecosystems." Thesis, University of Bristol, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373733.
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Limson, Janice. "Aging, sex, death (and heavy metals)." Rhodes University, 2011. http://hdl.handle.net/10962/d1019732.
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Xu, Yuping. "Interactions of heavy metals with minerals /." The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487856076412928.
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Cheung, Kai-him Matthew, and 張啟謙. "Bioremediation of toxic metals." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/194562.
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Traditional remediation techniques in removing toxic metal contaminants using physical and chemical methods are expensive and may cause other forms of damage to the environment, comparing with these techniques bioremediation can serve as an inexpensive, effective and environmental friendly remediation method. This thesis mainly discusses different bioremediation techniques and identifies possible areas in Hong Kong for bioremediation and suggests bioremediation methods for each potential area. Bioremediation of toxic metals is the use of microorganisms, plants, or even larger sized organisms to decontaminate sites with toxic metals.
Bioremediation includes phytoremediation, microremediation and vermiremediation which use plants, microorganisms and earthworms to remediate contaminated environments respectively. The 4 most common mechanisms in phytoremediation of toxic metals are phytoextraction, phytofiltration, phytovolatilization and phytostabilization. Phytoremediation are used frequently for remediation around the world and its development includes using well-understood technology and genetic engineering to increase its effectiveness. Microremediation is another promising technology in bioremediation of toxic metals and consists of 6 major mechanisms which are biosorption, bioaccumulation, biotransformation, bioleaching, biomineralization and microbially-enhanced chemisorption of metals.
Microremediation is mainly in research phase and its development includes identifying new species, combining with phytoremediation and genetic engineering. Vermiremediation is another rapidly developing technique in bioremediation of toxic metals, assisting other bioremediation by burrowing actions of earthworms and its excretion, and accumulating toxic metals inside their bodies. Vermiremediation is also in research phase but it is rapidly developing. Generally, bioremediation is around 60% cheaper than traditional remediation methods and no pollutants are emitted during the process. However the remediation process is slow and generally takes longer than a year. Sources of toxic metals in contaminated areas in Hong Kong are mainly due to historic industrial discharge although present activities also contribute. Potential areas include sites for electronic waste activities, sediments of Kwun Tong typhoon shelter and sediments of Tolo Harbour.published_or_final_version
Environmental Management
Master
Master of Science in Environmental Management
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Al-Asheh, Sameer. "Sorption of heavy metals by biological materials." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq26101.pdf.
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Warren, Robert Stephen. "Heavy metals in urban street surface sediments." Thesis, Middlesex University, 1987. http://eprints.mdx.ac.uk/13575/.
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A literature survey has been undertaken of the sources, levels and effects of heavy metal pollution in the urban street environment. Established techniques for the determination of heavy metal levels in urban dusts have been reviewed, and appropriate methods selected for use in the research project. Spatial and temporal variations of Cd, Cu, Pb and Zn in street dust have been investigated at a number sites. Metal loadings showed stronger spatial variation than concentrations with the greatest metal loadings occurring in the gutters and kerbsides. The results have been assessed in terms of surface type and condition, traffic loadings and antecedent weather conditions. The chemical associations of heavy metals in street dust, and their relationships to particle size have been investigated. Lead and Zn were associated mainly with carbonates and Fe-Mn oxides, whereas Cu is largely found in the organic fraction. Cadmium shows the greatest affinity for the exchangeable phase, and is therefore considered the most environmentally mobile metal studied. In addition to the studies mentioned above levels and chemical associations of heavy metals In school playground dust contaminated by paint flakes have been investigated. The levels of Pb were much higher than those previously reported. Exchangeable Pb concentrations represented a significant hazard to children playing in the area. In addition to the studies mentioned above levels and chemical associations of heavy metals In school playground dust contaminated by paint flakes have been investigated. The levels of Pb were much higher than those previously reported. Exchangeable Pb concentrations represented a significant hazard to children playing in the area. The final stage of the research project involved the operation of a sampling network to establish a mass balance for Cd, Cu, Pb and Zn within a residential urban street. Metal levels in atmospheric deposition, street sediments and runoff were monitored over an eight week period. Stormwater runoff was found to remove only a minor fraction of the metal deposited in the catchment during the sampling period.
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Agarwal, P. "Magnetism and superconductivity in heavy-fermion metals." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.595373.
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One of the key challenges of contemporary condensed matter physics is to understand how the large variety of states of matter arises in electron systems. While the basic force is in all cases the electrostatic Coulomb interaction, the variety of states of matter spans an impressively broad spectrum, ranging from insulators to superconductors, and including a variety of magnetic phases. In recent years, a series of new, emergent phenomena have added more exotic states to the list of known behaviour in metallic systems, and some of them defy the standard descriptions of 'normal' metals, known as Fermi liquid theory. Examples of these new phenomena include the fractional quantum-Hall effect, high temperature superconductivity and magnetic quantum phase transitions, which are at the focus of this dissertation. Such phase transitions occur when magnetic order is suppressed at low temperatures by means of an external control parameter, such as pressure, doping or applied field. In the vicinity of such a transition, unusual properties are expected due to strong, long range magnetic interactions, which can lead to unconventional normal states and, quite generally, to exotic forms of superconductivity. More specifically, I have studied high purity single crystals of two f-electron metals, namely CeNi2Ge2 and UGe2, both close to their critical lattice densities, and examined the behaviour of their electrical resistivity as a function of temperature and pressure. CeNi2Ge2 at ambient pressure is naturally very close to antiferromagnetic ordering, and for the first time, CeNi2Ge2 is shown to be an unconventional superconductor at ambient pressure at about Tc ≃ 200mK. Furthermore, the normal state of CeNi2Ge2 displays an unconventional power-law of the form Δp T1.2 over 2 decades in temperature. As pressure is applied a slow return to Fermi liquid behaviour is observed at the lowest temperatures, before a second (and as yet unidentified) ordered phase sets in at high pressures. The second system studied in this dissertation is the ferromagnet UGe2, in which magnetism can be suppressed by pressures of about 1.4 GPa. In this material, too, superconductivity is observed at low temperatures over a narrow pressure range, but in the ferromagnetically ordered phase. I present preliminary measurements together with a phase diagram. It seems that UGe2 is the first example of an itinerant ferromagnetic superconductor. Experimental work was carried out using a new adiabatic demagnetization cryostat, specially designed and built as an important part of the research project. The thesis describes the design of the instrument, which allows high sensitivity measurements of the resistivity over a wide range in temperature with high reliability.
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Mowll, J. L. "The responses of fungi to heavy metals." Thesis, University of Dundee, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234237.
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Mansi, Sadoniben E. "Heavy metals and their ecotoxicology in estuaries." Thesis, University of Essex, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426006.
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Md, Noh Mohd Fairulnizal. "Electrochemical sensors development for toxic heavy metals." Thesis, Cranfield University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422358.
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Wainaina, Steven. "Effect of heavy metals on syngas fermentation." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-10203.
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The goal of this work was to establish the suitable and limiting concentrations of Zn, Cu and Mn compounds during syngas fermentation. The results showed that cells encased in polyvinylidene difluoride (PVDF) membranes had a faster accumulation of methane in reactors containing fermentation medium dosed with 5 mg/L of each heavy metal compared to free cells. It was also revealed that total inhibition of biohydrogen production occurred in medium containing 5 mg/L Cu, 30 mg/L Zn and 140 mg/L Mn while the most suitable metal concentration level was 0.1 mg/L Cu, 0.6 mg/L and 2.8 mg/L Mn. In addition, a comparison test showed that for the most suitable metal concentration in the medium, rate of performance at pH 6 and 7 was higher than at pH 5.
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Kirk, Charles A. C. "Geochemical fractionation of heavy metals in soils." Thesis, University of Bristol, 1995. http://hdl.handle.net/1983/2153b6ab-75d5-4b4f-b648-f3ff6795b4d9.
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Santos, Pedro Deyrieux Centeno Ogando. "Heavy metals removal in dual media filters." Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/8251.
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Dissertação para obtenção do Grau de Mestre em
Engenharia do Ambiente – Perfil de Engenharia SanitáriaThe purpose of this study was to investigate physicochemical mechanisms for the removal of heavy metals from the effluent of Harnaschpolder’s WWTP Pilot Installation in the South of Netherlands. This effluent is partially submitted to tertiary treatment in a water reuse pilot which aims the production of water for two different end‑uses: crop irrigation in greenhouses and surface‑type water. Tertiary filters were mounted and started up at the reuse pilot and specific concentrations of heavy metals were dosed in the filters. Removal efficiencies were then calculated after the end of the experiments. As a parallel research project, the removal of HM was also carried out by inoculating selected bacteria (biosorption). Solubility curves were calculated for the dosed heavy metals (Cd, Cu, Ni, Zn) using PHREEQc programme, to predict if heavy metal precipitation occurred in the filters (using the same experimental data: temperature, pH , alkalinity, etc.). Results show that physicochemical precipitation was not the primary removal mechanism for heavy metals. The results suggest that other mechanisms such as adsorption and/or chelation may be involved in the removal of these species.
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Lindström, Martin. "Predictive Modelling of Heavy Metals in Urban Lakes." Doctoral thesis, Uppsala University, Department of Earth Sciences, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-530.
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Heavy metals are well-known environmental pollutants. In this thesis predictive models for heavy metals in urban lakes are discussed and new models presented. The base of predictive modelling is empirical data from field investigations of many ecosystems covering a wide range of ecosystem characteristics. Predictive models focus on the variabilities among lakes and processes controlling the major metal fluxes.
Sediment and water data for this study were collected from ten small lakes in the Stockholm area, the Eastern parts of Lake Mälaren, the innermost areas of the Stockholm archipelago and from literature studies. By correlating calculated metal loads to the land use of the catchment areas (describing urban and natural land use), the influences of the local urban status on the metal load could be evaluated. Copper was most influenced by the urban status and less by the regional background. The opposite pattern was shown for cadmium, nickel and zinc (and mercury). Lead and chromium were in-between these groups.
It was shown that the metal load from the City of Stockholm is considerable. There is a 5-fold increase in sediment deposition of cadmium, copper, mercury and lead in the central areas of Stockholm compared to surrounding areas.
The results also include a model for the lake characteristic concentration of suspended particulate matter (SPM), and new methods for empirical model testing. The results indicate that the traditional distribution (or partition) coefficient Kd (L kg-1) is unsuitable to use in modelling of the particle association of metals. Instead the particulate fraction, PF (-), defined as the ratio of the particulate associated concentration to the total concentration, is recommended. Kd is affected by spurious correlations due to the definition of Kd as a ratio including SPM and also secondary spurious correlations with many variables correlated to SPM. It was also shown that Kd has a larger inherent within-system variability than PF. This is important in modelling.
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Claus, Sonia Carmel, University of Western Sydney, of Science Technology and Environment College, and of Science Food and Horticulture School. "Heavy metals in biota from temperate Australian estuaries." THESIS_CSTE_SFH_Claus_S.xml, 2003. http://handle.uws.edu.au:8081/1959.7/503.
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The detection of anthropogenic impacts in our estuaries has become a critical social, political and scientific concern in recent years. Work has focussed on the effects of these impacts on the spatial and temporal patterns of biotic assemblages and searched for bioindicators and biomarkers of pollutants that may act as early warning signs. The estuaries in temperate Southeastern Australia have a diversity of biotic assemblages living in the soft sediment. One of the most abundant macroinvertebrates is the little studies mussel, Xenostrobus securi that is found living with an assemblage of benthic biota including amphipods, crabs, isopods and tanaids, bivalves and gastropods. Two commercial fish species bream and mullet also inhabit these estuaries. Numerous stormwater drains can be found entering the estuaries through the mangrove forests lining the shores. Along with inputs of freshwater, stormwater drains are thought to be responsible for the entry of heavy metals into estuaries. These heavy metals have the potential to alter the patterns of biotic assemblages and bioaccumulate in the tissues of miacroinvertebrates, mussels and fish living within temperate estuaries. Over the time of this study the concentrations of heavy metals in the sediment tissues and shell of X.Securis varies spatially and temporally. Although this study adds substantially to current knowledge there is still more that is needed to establish X. Securis as a bioindicator. Questions remain about uptake, depuration and response to environmental gradients of heavy metals in X. Securis. Before X Securis can be used routinely in monitoring heavy metal contamination these questions need to be further investigatedDoctor of Philosophy (PhD)
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Lindström, Martin. "Predictive modelling of heavy metals in urban lakes /." Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2000. http://publications.uu.se/theses/91-554-4854-2/.
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Claus, Sonia Carmel. "Heavy metals in biota from temperate Australian estuaries /." View thesis, 2003. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20051013.092820/index.html.
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Thesis (Ph.D.) -- University of Western Sydney, 2003."Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy at the University of Western Sydney Hawlesbury" Bibliography : leaves 245-278.
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Li, Litong. "Heavy metals removal from wastewater by peat absorption /." Connect to online version, 1996. http://hdl.handle.net/1989/3561.
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Rose, C. J. S. "The uptake of heavy metals by three seaweeds." Thesis, Swansea University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638712.
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Khastoo, D. "Uptake and toxicity of heavy metals in insects." Thesis, Swansea University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637787.
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The effects of some heavy metals at different stages of food chains are examined. The uptake of Zn or Cd by Australian white wheat, Triticum aestivum, was investigated and this wheat fed to the herbivore, Schistocerca gregaris. The organs of these insects were then examined for accumulation. Accumulation occurred in all organs examined but was higher in the epidermis and mid-gut. Nasonia vitripennis (Hymenoptera) was used as a carnivore. The effects of Zn, Cd, Cu and Hg on the longevity and survival of this insect were examined together with total accumulation at three different temperatures. Metals were more toxic at higher temperatures and the effects of different metals varied. The effects on the ultrastructure of flight muscles were examined, the main effect being a disruption of the mitochondria.
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Kwan, Sai-ping, and 關世平. "Heavy metals in Hong Kong rabbitfish (Siganus canaliculatus)." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31221038.
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Jones, J. M. "Magnetic minerals and heavy metals in ombrotrophic peat." Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372671.
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Muhammad, Nur. "Removal of heavy metals by slow sand filtration." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/6981.
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Slow sand filters (SSFs) are probably the most effective, simplest and least expensive water treatment process. Micro-organisms and other particulate materials are effectively removed by SSFs. Considerable development has been done on SSFs with respect to particle removal, but only a few works have been reported in the context of the removal of heavy metals which are a severely toxic pollutant of surface waters. No extensive laboratory or pilot studies have been carried out to determine the performance or the mechanisms of removal of heavy metals by SSFs. This research is concerned with an experimental investigation of the removal of heavy metals from surface water by SSFs. Four laboratory scale SSFs were built and run according to standard design criteria. Removal of four common heavy metals [copper (Cu), chromium (Cr), lead (Pb) and cadmium (Cd)] were monitored. The filters were fed synthetic water made from tap water mixed with settled sewage, and each filter was dosed with one of the heavy metal salts. The concentrations of Cu, Cr, Pb and Cd in the influent were selected as 10 mg/l, 100 μg/l, 60 μg/l, and 100 μg/l respectively considering their relative toxicity and WHO guidelines in drinking water. Settled sewage was added to vary the total organic carbon (TOC) of the feed water. The reduction of heavy metal concentrations were monitored at various TOCs, filtration rates and filter bed depths. The results showed that SSFs succeeded in removing heavy metals from water. The removals of Cu, Cr, Pb and Cd at the conventional flow rate and filter depth are 99.6,97.2,100 and 96.6 % respectively. The results also showed that an increase in TOC in the feed water improved metal removal while increases of flow rates caused a decrease of the removal of metals. The removal of heavy metals also decreased with a reduction in sand bed depth. The optimisation of design parameters for SSFs for the removal of heavy metals depends on the individual heavy metal and on the TOC content of the feed water. Model equations were developed for, and linear correlation was observed between each of the three control parameters and the removal of the selected metal. The removal of heavy metal by SSFs was achieved through the combination of a number of mechanisms. Settlement, adsorption to both sand and organic matter and microbial
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Rome, Jacqueline Louise de. "Biosorption of heavy metals by fungi and yeast." Thesis, University of Dundee, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338281.
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Tompkins, Joanne Deborah. "The uptake of heavy metals into human phagocytes." Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243177.
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Kwan, Sai-ping. "Heavy metals in Hong Kong rabbitfish (Siganus canaliculatus) /." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20667759.
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Paul, Uchenna Prince. "Fluorescence Detectors for Proteins and Toxic Heavy Metals." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd416.pdf.
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PINO, GABRIELA ALEJANDRA HUAMAN. "BIOSSORPTION OF HEAVY METALS ON GREEN COCONUT POWDER." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2005. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=7596@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOA poluição por metais pesados vem se tornando um sério problema ambiental. O uso de biomassas como material sorvente para a destoxificação de efluentes industria is contendo metais aparece como uma alternativa promissora às tecnologias existentes. O objetivo desta dissertação foi determinar a capacidade de adsorção da casca de coco (Cocos nucifera) para diferentes metais pesados. No processo de biossorção foram ava liados o pH da solução, a concentração inicial dos íons metálicos, o tamanho de partícula e a cinética do processo. As características da superfície da casca de coco foram investigadas utilizando medições de potencial zeta e análises com microscópio eletrônico de varredura. Obtiveram-se altas percentagens de remoção para o Cd, Cr(III) e Cr(VI) dentre as seis espécies metálicas estudadas (As(V), Cd, Cr(III), Cr(VI), Ni e Zn). Os valores ótimos de pH utilizados foram de 7 para o cádmio e cromo (III) e de 2 para o cromo (VI). Em concentrações inicias inferiores a 100 mg/L foram obtidas percentagens de remoção superiores a 95%, 85% e 80% para o cádmio, cromo (III) e cromo (VI), respectivamente. Em concentrações inicias menores que 1000 mg/L, a percentagem de remoção para o cádmio e o cromo (III) foi de 80% e 85%, respectivamente. Foram utilizados os modelos de Langmuir e Freundlich para avaliar a capacidade de adsorção de metais pesados pela casca de coco. O modelo de Langmuir mostrou-se mais adequado para o cádmio e o cromo (VI), enquanto que para o cromo (III) o modelo de Freundlich foi o mais adequado. A cinética do processo de biossorção foi estudada para o cádmio mediante as análises integral e diferencial. Foi observado que o processo de biossorção de cádmio por casca de coco verde obedece a um modelo de pseudo-segunda ordem. Os resultados apresentados mostram que a casca de coco apresenta as características apropriadas para o processo de biossorção de cádmio, cromo (III) e cromo (VI) e que pode ser utilizada como uma alternativa aos processos clássicos de destoxificação de efluentes.
Heavy metal pollution has become one of the most serious problems today, and the use of organic material biomass for the detoxification of industrial effluents for environmental protection offers a potential alternative to existing trea tment technologies. The aim of this work was determined the biosorption capacity of coconut fibers (Cocos nucifera) for different heavy metals. The effect of pH, initial concentration, size of particle and kinetics were studied. The characteristics of the surface of coconut fibers had been investigated using measurements of potential zeta and analyses with scanning electron microscope. The removal was found to be higher for cadmium, chromium (III) e chromium (VI) among the 6 metallic species studied (As, Cd, Cr (III), Cr (VI), Ni e Zn). The values of pH used were 7 for cadmium and chromium (III) and of 2 for chromium (VI). For cadmium, chromium (III) and chromium (VI), with an initial metal concentration lower than 100 mg/L, removal rates of 95%, 85% and 80% respectively had been observed. For cadmium and chromium (III), with an initial concentration lower than 1000 mg/L, removal rates of 80% and 85% respectively were found. The adsorption capacity of coconut fibers for heavy metals had been evaluated using Langmuir and Freundlich adsorption isotherms. The Langmuir´s model gave best results for cadmium and chromium (VI) and Freundlich´s model for chromium (III). The kinetics of the process was studied just for cadmium, because it presented the best removal rates. The kinetics study showed that the biosorption process followed a pseudo second order model. This suggests that coconut fibers represent a good option for biosorption process and can be used as an alternative to the classical technologies for effluent decontamination.
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Chatterjee, Sabyasachi. "Calcite and Calcium Oxalate Sequestration of Heavy Metals." Diss., Temple University Libraries, 2009. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/50093.
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EngineeringPh.D.
Heavy metals like cadmium, lead and zinc pose a significant threat to human health and environment. Several factors such as pH, EH, organic matter and clay content of the soil affect the bioavailability of such heavy metals in the environment. The presence of several naturally occurring minerals such as calcite (calcium carbonate, CaCO3) and calcium oxalate (CaC2O4.) in the environment significantly influence the fate and transport of some of the heavy metal cations. Sequestration of heavy metals such as cadmium (Cd) and zinc (Zn) from solution by calcite has been clearly demonstrated in the literature. However, studies on heavy metal sequestration by calcite and calcium oxalate from a multi-metal environmental that represents real world situations are rare. In this contribution, column flow studies of Cd and Zn sequestration by calcite exposed to influent solutions saturated or non-saturated with calcite and containing either 1 mg/L of Cd, 1 mg/L of Zn or combined 1 mg/L of Zn and Cd, followed by desorption of the sequestered metals were conducted. Complementary scanning electron microscopy (SEM) coupled with electron dispersive x-ray spectroscopy (EDS) data were generated. Kinetic studies show that reaction rates of Cd and Zn with calcite are governed by a simple rate law with reaction orders of less than 1 (0.02 - 0.07) indicating at least mathematically, the occurrence of reactions that went to completion if the reaction orders did not change. When the influent solution contains a single cation, the rate of Zn removal from solution by calcite and calcium oxalate is greater than Cd removal rate. However in a multi-cation environment, cadmium removal rate was greater than zinc removal rate. MINTEQA2 a geochemical equilibrium speciation model was used to compute the equilibrium between the various species in the cation-calcite environment. Complimentary desorption studies and surface SEM/EDS analysis indicate that the removal of Cd and Zn from solution by calcite and calcium oxalate is probably due to precipitation/complexation reaction. The SEM and EDS results appear to confirm the presence of a precipitate on the mineral surface in the case of the influent solution containing Zn. The current research also examines the effect of citrate, a commonly present urinary tract species on calcium oxalate dissolution. The dissolution studies indicate that citrate solution is capable of dissolving sodium oxalate at high pH. The dissolution of calcium oxalate results in the release of heavy metals that were previously sequestered within the mineral. Results show that a greater percentage of zinc was removed than cadmium, from calcium oxalate due to its dissolution by citrate.
Temple University--Theses
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Sekhula, Koena Sinah. "Heavy metal ion resistance and bioremediation capacities of bacterial strains isolated from an Antimony Mine." Thesis, University of Limpopo, 2005. http://hdl.handle.net/10386/139.
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Thesis (M.Sc.) -- University of Limpopo, 2005Six aerobic bacterial strains [GM 10(1), GM 10 (2), GM 14, GM 15, GM 16 and GM 17] were isolated from an antimony mine in South Africa. Heavy-metal resistance and biosorptive capacities of the isolates were studied. Three of the isolates (GM 15, GM 16 and GM 17) showed different degrees of resistance to antimony and arsenic oxyanions in TYG media. The most resistant isolate GM 16 showed 90 % resistance, followed by GM 17 showing 60 % resistance and GM 15 was least resistant showing 58 % resistance to 80 mM arsenate (AsO4 3-). GM 15 also showed 90 % resistance whereas isolates GM 16 and GM 17 showed 80 % and 45 % resistance respectively to 20 mM antimonate (SbO4 3-). Arsenite (AsO2 -) was the most toxic oxyanion to all the isolates. Media composition influenced the degrees of resistance of the isolates to some divalent metal ions (Zn2+, Ni2+, Co2+, Cu2+ and Cd2+). Higher resistances were found in MH than in TYG media. All the isolates could tolerate up to 5 mM of the divalent metal ions in MH media, but in TYG media, they could only survive at concentrations below 1 mM. Also, from the toxicity studies, high MICs were observed in MH media than TRIS-buffered mineral salt media. Zn2+ was the most tolerated metal by all the isolates while Co2+ was toxic to the isolates. The biosorptive capacities of the isolates were studied in MH medium containing different concentrations of the metal ions, and the residual metal ions were determined using atomic absorption spectroscopy. GM 16 was effective in the removal of Cu2+ and Cd2+ from the contaminated medium. It was capable of removing 65 % of Cu2+ and 48 % of Cd2+ when the initial concentrations were 100 mg/l, whereas GM 15 was found to be effective in the biosorption of Ni2+ from the aqueous solutions. It was capable of removing 44 % of Ni2+ when the initial concentration was 50 mg/l. GM 17 could only remove 20 % of Cu2+ or Cd2+. These observations indicated that GM 16 could be used for bioremediation of xvi Cu2+ and Cd2+ ions from Cu2+ and Cd2+-contaminated aqueous environment, whereas GM 15 could be used for bioremediation of Ni2+.
National Research Foundation and the University of the North Research Unit