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Jia, Yong Feng. "Adsorption of heavy metal ion species from aqueous solution in activated carbon." Thesis, University of Newcastle Upon Tyne, 2000. http://hdl.handle.net/10443/519.
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Activated carbons are used widely for the adsorption of environmentally unfriendly species from both liquid and gas phases, the separation of gases and adsorption of species from aqueous solution. Examples of the processes are the adsorption of Au(CN)2 and Ag(CN)2 from aqueous solution for the recovery of precious metals, the treatment of waste water containing organic chemicals and toxic metal species and the preparation of metal catalysts supported on carbon. This investigation has involved the study of the influence of porous structure and surface functional groups on the adsorption of both anionic and cationic metal species in order to understand the mechanism of adsorption of these species on active carbon from aqueous solution. Various types of oxygen functional groups were introduced onto the surface of coconut shell derived activated carbon through oxidation using nitric acid. Fourier transform infrared spectroscopy (FTIR), temperature programmed desorption (TPD) and selective neutralisation were used to characterise the surface oxygen functional groups. The oxidised carbons were also heat treated to provide a suite of carbons where the oxygen functional groups of various thermal stability were varied progressively. It was found that acidic oxygen functional groups mainly as carboxylic acid groups were incorporated into activated carbon by HNO3 oxidation. The phenol and quinone groups were also introduced by the oxidation process while the lactone groups were formed during heat treatment. The oxygen functional groups had a range of thermal stabilities with carboxylic acid groups being the least stable. A coconut shell derived active carbon was treated with ammonia and nitric acid followed by ammonia to incorporate nitrogen functional groups into the carbon. Active carbon with high nitrogen content was also prepared from nitrogen-rich precursor polyacrylonitrile (PAN). X-ray absorption near edge structure spectroscopy (XANES) and FTIR were used to investigate the structures of the nitrogen functional groups in carbons. The possible nitrogen functional groups present on carbon surface were pyridinic, pyrrolic (or indolic), pyridonic and aromatic amine-like structures. The adsorption characteristics of gold and silver cyanide anionic species on a suite of active carbons derived from coconut shell, polyacrylonitrile and chemical modification of the coconut shell carbon were investigated. The gold and silver cyanide adsorption capacities for coconut shell derived carbons correlate with total pore volume. Nitric acid oxidation treatment of the carbon was detrimental to gold adsorption in spite of the incorporation of oxygen content of carbon. The influence of nitrogen functional groups in the carbon structure on gold and silver adsorption was investigated using carbons derived from polyacrylonitrile. The addition of ethanol and butanol to the solution had an adverse effect on gold adsorption. Adsorption of silver cyanide ionic species on the active carbon was suppressed in the presence of excess free cyanide ions in solution whereas gold cyanide adsorption was not greatly affected at room temperature. The adsorption of gold cyanide was suppressed by the excess free cyanide and sodium sulphide at 70 °C. The adsorption of cadmium ions was enhanced dramatically by oxidation of the carbon. The ratio of released proton to adsorbed cadmium on oxidised carbon was approximately 2 indicating cation exchange was involved in the adsorption process. Na+ exchange studies with the oxidised carbon gave a similar ratio. After heat treatment of the oxidised carbons to remove oxygen functional groups, the ratio of H+/Cd2+ decreased significantly as well as the adsorption capacity. Both reversible and irreversible adsorption were involved in the process of cadmium adsorption with reversible adsorption having higher enthalpy. The irreversible adsorption resulted from cation exchange with carboxylic acid groups whereas the reversible adsorption probably involved physisorption of the partially hydrated cadmium ion. The nitrogen functional groups may act as ligands which can coordinate with transition metal cations. The adsorption of transition metal cations such as Cd 2+, Ni2+ and Cu2+ on active carbon was appreciably increased by the nitrogen functional groups present on carbon surface whereas ammonia treatment of the carbon showed little effect on the adsorption of alkali earth metal cation Cat+. There is little difference in the adsorption capacities of cadmium ions on coconut shell derived carbon at pH 4.1 and pH 7 whereas the adsorption of cadmium ions was significantly enhanced with increasing pH for the carbons with high nitrogen content. The nitrogen rich carbons show selectivity towards various transition metal cations reflected by adsorbing more Cu 2+ than Cd2+. This is consistent with the fact that the coordination compound of Cu 2+ with pyridine has higher stability constant than that of cadmium.
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Dietrich, Theo Henry. "The removal of heavy metals from dilute aqueous streams by the use of ion exchange resins." Thesis, Cape Technikon, 1998. http://hdl.handle.net/20.500.11838/887.
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Thesis (MTech (Chemical Engineering)--Cape Technikon, Cape Town, 1998Ion exchange resins are widely used to remove or concentrate heavy metals from aqueous solutions or slurries.This thesis attempts to properly evaluate the interaction between ion exchange resins and heavy metals at trace metal concentrations.The durability of the resins and their effectiveness in real slurries were also investigated. In this study, a chelating resin, as well as a cation, and anion exchange resin was contacted with aqueous solutions of heavy metals in both free and complexed form. Zinc, nickel and copper cyanide complexes were adsorbed onto the anion exchange resin, while the chelating and cation exchange resins were contacted with zinc and nickel nitrates, and cupric sulphate. All the tests were conducted in batch stirred tank reactors. All the metal cyanide complexes behaved in a similar manner when contacted with the anion exchange resins. These tests were p~rf0nned under variations in temperature, stirring speed, pH., ionic strength and . initial metal 90E~entrations. Fitting of a dual resistance model to the profiles for thetlptllk:e" of the complexes, show that both film diffusion and intraparticle diffusion rates were improved with an increase in temperature, and that film diffusion rates improved with an increase in stirring speed. A high ionic strength negatively affected equilibrium loading as well as diffusional rates.It was found that at these low concentrations, the diffusional rates improves with a decrease in the external metal concentration. A comparative study involving the chelating and cation·exchange resins were performed, during which the resins were contacted with the metals in free fonn. It was found that at high metal concentrations, the chelating resin induced a rate limiting effect, but at trace concentrations, this effect is virtually negated. Whereas the cation exchange resin exhibited little selectivity in adsorbing the metals, it was found that the chelating resin prefers the metals in the eu > Ni > Zn. The chelating resin proved to be no less durable then the cation exchange resin, and both slightly lost their ability to adsorb the metal cations as a result of the effects of an inert coarse sand slurry.Tests performed with a real ore leachate, showed the cation exchange resin to be efficient at a low pH , but also relatively non selective, since the adsorption of copper from the leachate was greatly reduced due to the presence of other heavy metals.
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Kothalawala, Kothalawalage Nuwan. "Nanoporous high surface area silicas with chelating groups for heavy metal ion adsorption from aqueous solution /." View online, 2010. http://repository.eiu.edu/theses/docs/32211131524422.pdf.
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Keleşoğlu, Serkan Polat Hürriyet. "Comparative adsorption studies of heavy metal ions on chitin and chitosan biopolymers/." [s.l.]: [s.n.], 2007. http://library.iyte.edu.tr/tezlerengelli/master/kimya/T000622.pdf.
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Huang, Jing. "Functional Polymers Containing Semi-Rigid Alternating Sequences." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/89884.
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Alternating copolymers represent a special class of copolymers in which the two comonomers copolymerize in a regular alternating sequence along the polymer chain. Of particular interest in our group are the stilbene-maleic anhydride/maleimide alternating copolymers. These copolymers possess sterically congested backbones and precisely placed functional groups arising from the strictly alternating copolymerization. The research in this dissertation is focused on the synthesis, characterization, and potential application of functionalized copolymers that contain semi-rigid alternating copolymer sequences.
The fluorescence properties of a series of non-conjugated, tert-butyl carboxylate functionalized alternating copolymers were investigated. Extraordinarily high fluorescent intensity with excellent linearity was observed for the di-tert-butyl group-containing stilbene and maleic anhydride alternating copolymer in THF. We attributed the origin of the strong fluorescence to the “through space” π – π interactions between the phenyl rings from the stilbene and C=O groups from the anhydride. The fluorescence was maintained when the copolymer was deprotected and hydrolyzed and the resulting carboxylic acid-functionalized copolymer was dissolved in water at neutral pH.
The tert-butyl carboxylate functionalized alternating copolymer sequences were incorporated into highly crosslinked polymer networks using suspension polymerization. After removing the tert-butyl groups by acidic hydrolysis, the surface area of the networks increased significantly. Using this facile two-step strategy, we were able to achieve nanoporous polymers with BET surface area up to 817 m2/g and carboxylic acid-functionalized surfaces. The BET surface area of deprotected polymers increased with increasing crosslinking density, and the stilbene-containing polymers showed systematically higher BET surface area than the styrene-containing polymers due to the stiffness of the alternating sequences. The resulting nanoporous polymers have potential to be employed as solid sorbents for CO2.
The same tert-butyl carboxylate functionalized alternating copolymer sequences were also incorporated into microgels via miniemulsion polymerization. The miniemulsion technique ensured the successful synthesis of microgels with ~100 nm diameter using solid stilbene and maleimide monomers. The resulting tert-butyl carboxylate-containing microgels were converted into carboxylic acid-containing aqueous microgels by acid hydrolysis. These aqueous microgels showed good and reversible lead and copper ion adsorption capacities.
Amine-functionalized nanoporous polymers were synthesized by the post-modification of highly-crosslinked divinylbenzene-maleic anhydride polymers. High amine-contents were achieved by covalently attaching multiamines to the acid-chloride functionalized polymer surface. The resulting polymers showed medium to high BET surface areas (up to 500 m2/g) and high CO2 capture capacities.PHD
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Ogunleye, Adetoro O. "Bacterial poly-gamma-glutamic acid (γ-PGA) : a promising biosorbent of heavy metals." Thesis, University of Wolverhampton, 2015. http://hdl.handle.net/2436/579925.
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Poly-γ-glutamic acid (γ-PGA) is a biopolymer made up of repeating units of L-glutamic acid, D-glutamic acid or both. γ-PGA is water soluble, non-toxic and biodegradable, and can be used safely in a variety of applications that are increasing rapidly. This study investigated the production of HMW γ-PGA by five Bacillus species (B. licheniformis 1525, B. licheniformis NCTC 6816, B. licheniformis ATCC 9945a, B. licheniformis ATCC 9945a and B. subtilis (natto) ATCC 15245) in GS, C and E media for the removal of heavy metals in wastewaters. The highest γ-PGA yields of 11.69 g/l and 11.59 g/l were produced by Bacillus subtilis (natto) ATCC 15245 in GS medium and medium C respectively. Upon characterization, γ- PGAs with different properties (crystallinity, acid/salt form and molecular weights ranging from 2.56 × 105 Da to 1.65 × 106 Da) were produced. The water soluble, non-toxic, HMW (Mw 1.65 × 106 Da) γ-PGA produced by B. subtilis (natto) ATCC 15245 in medium C was investigated as a sorbent for the removal of heavy metal ions including Cu2+, Zn2+, Ni2+, Cd2+ and Ag+. The results showed that the removal of metals by γ-PGA was more dependent on the concentration of γ-PGA than the solution pH. The highest metal ions removal of 93.50%, 88.13%, 90.21%, 90.56% and 86.34% by HMW γ-PGA were obtained for Cu2+, Zn2+, Ni2+, Cd2+ and Ag+ respectively. The presence of interfering metal ions could hinder the adsorption of individual metal ions by γ-PGA. The affinities of heavy metal ions for γ-PGA followed the order: Cu2+ > Zn2+ > Ni2+ > Cd2+. The effect of molecular weight of γ-PGA on metal removal was also investigated, and it was found that metal ion adsorption capacity of γ-PGA strongly depended on its molecular weight. The maximum amount (93.50%) of Cu2+ sorbed by HMW γ-PGA was higher compared to that (59.48%) sorbed by LMW γ-PGA. Isotherm models showed that the Redlich-Peterson best described the metal adsorption capacity of γ-PGA. It was also found that a multisite adsorption mechanism occurred via the complexation of metal ions with the free α-carboxyl and possibly the amide functional groups in γ-PGA.
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Terdkiatburana, Thanet. "Simultaneous removal process for humic acids and metal ions by adsorption." Curtin University of Technology, Dept. of Chemical Engineering, 2007. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=18564.
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Humic substances are macromolecules that naturally occur in all environments in which vegetation matter are present. In general, humic acid is part of humic substances which form the major fraction of the dissolved organic matters in surface water and represents 90% of dissolved organic carbon. Humic acid plays a fundamental role in many ecosystems since it interacts with toxic metal ions present in the system, resulting in a decrease in the bio-availability of such ions. Moreover, the availability of humic acid in water can react with other chemical compounds, such as chlorine to form trihalomethanes (including chloroform) and causes an increasing risk of cancer and may be linked to heart, lung, kidney, liver, and central nervous system damage. Therefore, humic acid removal in water treatment processes is very important in order to achieve the drinking water standards. Heavy metals are significant contaminants in aqueous system. All heavy metals can produce toxicity when ingested in sufficient quantities, but there are several important ones such as lead, mercury, copper, cadmium, arsenic, nickel and silver. These heavy metals are so pervasive and produce toxicity at low concentrations. Moreover, they may build up in biological systems and become a significant health hazard.Adsorption is approved as an effective and simple method for water and wastewater treatment process. Many adsorbents then are developed for use in adsorption process such as montmorillonite, peat, activated carbon, etc. In this research, humic acid and heavy metals were mainly selected for adsorption study. In the sorption experiment, several adsorbents such as synthesised zeolite (SZ), natural zeolite (NZ), powdered activated carbon (PAC) and fly ash (FA), were selected to examine the application of HA and heavy metals both in individual and simultaneous adsorption, The characteristics and interactions of the adsorbents with HA and heavy metals were systematically studied by batch laboratory experiments. In the beginning, the adsorption of HA onto SZ, NZ, PAC and FA was investigated and their adsorption capacity was compared. The equilibrium adsorption of HA on SZ, NZ, PAC and FA was found to be 84.1, 67.8, 81.2 and 34.1 mg/g, respectively, at 30 oC and pH 5.0. Dynamic adsorption data show that these adsorbents could reach their adsorption equilibrium after 50 hours. From pH analysis, HA adsorption is favoured at low pH and an increase in pH will lead to the reduction of HA adsorption. SZ and NZ adsorption capacity were affected by the changing of solution temperature; however, in PAC and FA sorption study, there was no significant effect observed. Two heavy metal ions (Cu, Pb) removal by the adsorbents was then conducted. The results showed that the equilibrium sorption capacity of Cu and Pb ions on SZ, NZ, PAC and FA were 43.5, 24.2, 19.7, 28.6 and 190.7, 129.0, 76.8 mg/g, respectively at 30 oC and a pH value of 5. The appropriate pH for Cu and Pb removal was found to be 5 and 6. In most dynamic cases, these adsorbents needed at least 50 hours to reach the adsorption equilibrium. Only adsorption on FA required more than 150 hours to reach the equilibrium.
In simultaneous adsorption experiments, the influences of HA and heavy metal concentration (in the range of 10 to 50 mg/L for HA and 10 to 30 mg/l for heavy metals) on the HA-heavy metal complexation were investigated. The results demonstrated that increasing HA concentration mostly affected Cu adsorbed on SZ, FA and PAC and Pb adsorbed on SZ, NZ and PAC. For HA adsorption, the adsorption rate decreased rapidly with increased initial metal ion concentration. Moreover, the adsorption of heavy metals increased with increased heavy metals concentration in the presence of HA. In the presence of heavy metal ions, the order of HA adsorption followed PAC > FA > SZ > NZ. According to the results, the individual and simultaneous adsorption of HA and heavy metals on each adsorbent achieved a different trend. It mainly depended on the adsorption property of both adsorbates (HA and heavy metals) and adsorbents (SZ, NZ, PAC and FA) and also the operation factors such as pH, concentration, temperature and operation time. Even though this experiment could not obtain high adsorption performance, especially in coadsorption, as compared with other adsorbents, the adsorbents in this study represented a higher adsorption capacity and provide the potential for further development.
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Turemen, L. M. "Investigation of the adsorption of reactive dyes and heavy metal ions from synthetic textile effluent by eggshell membrane." Thesis, Queen's University Belfast, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368526.
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Sabolč, Pap. "Novi adsorpcioni medijumi za separaciju neorganskih polutanataotpadnih voda bazirani na termohemijskoj konverziji biomase." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2017. https://www.cris.uns.ac.rs/record.jsf?recordId=104791&source=NDLTD&language=en.
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Salih, Ali Mohammed. "The purification of industrial wastewater to remove heavy metals and investigation into the use of zeolite as a remediation tool." Thesis, University of Wolverhampton, 2018. http://hdl.handle.net/2436/621859.
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Zeolites are well-known aluminosilicate minerals that have been widely used as adsorbents in separation, purification processes and environmental pollution control. Zeolites are used in various industrial applications due to their high cation-exchange ability, molecular sieve and cataltic properties. In order to reduce the costs of acquisition and minimise the disposal of adsorbents, both modified natural zeolite and synthetic zeolite (derived from kaolinite) were used for the purification of wastewater. The characteristic properties and applications of adsorbents are also discussed including the advantages and disadvantages of each technique. The present work involves the study of the removal of Cu2+, Fe3+, Pb2+ and Zn2+ from synthetic metal solutions using natural zeolite. Laboratory experiments were used to investigate the efficiency of adsorbents in the uptake of heavy metals from industrial wastewater. These include equilibrium tests, kinetic studies and regeneration studies. The physical and chemical characterization of the zeolites was carried out using different analytical techniques such as Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X - Ray Diffraction (XRD), X - Ray Fluorescence (XRF), Thermogravimetric Analysis (TGA), Fourier Transform Infrared (FT-IR) Spectroscopy and Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES). The kinetic study indicated the suitability of the natural zeolite for the removal of Cu2+, Fe3+, Pb2+ and Zn2+ ions from synthetic wastewater. Batch experiments were used to identify the effect of parameters that affect the rate of adsorption such as the effect of adsorbent mass, effect of adsorbent particle size, effect of initial solution pH, effect of initial solution concentration, effect of agitation speed and effect of pre-treatment of adsorbent and evaluated their impact on the efficiency of the zeolite in the removal of heavy metals from industrial wastewater. The kinetic studies showed that the capacity of the adsorbents for the removal of heavy metals increased with a greater mass of absorbent, increased initial solution pH, increased agitation speed, higher solution concentration as well as the application of a pre-treatment. The results from the equilibrium studies positively demonstrated that natural zeolite can be used as an excellent adsorbent for removing heavy metals from multi-component solutions. The equilibrium experiments indicated that the capacities of natural zeolite for the uptake of heavy metals increased when the initial solution pH increased. The results indicated that the maximum removal capacities Q were 22.83, 14.92, 14.49 and 17.54 mg/g natural zeolite for copper, iron, zinc, and lead respectively. Both the Langmuir and Freundlich isotherm models were used to characterize the experimental data and to assess the adsorption behaviour of natural zeolite for copper, iron, lead and zinc. The experimental data were slightly better suited to the Langmuir isotherm than the Freundlinch isotherm. The value of the correlation coefficients r2 ranged from 0.93 to 0.99 for the Langmuir isotherm and from 0.90 to 0.99 for the Freundlich isotherm. The present work also involved the study of synthetic zeolite A, which was derived from natural kaolinite. The conversion of the raw materials into zeolitic materials was carried out in two ways: first, conventional hydrothermal synthesis and second, alkaline fusion prior to hydrothermal synthesis. The results from both routes show that zeolite A was synthesised successfully. Finally, the experiments show that both natural and synthetic zeolites can be available in commercial quantities. Synthetic zeolites are more attractive for some specific applications, while the cheapness of natural zeolite may favour its use.
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Albarelli, Juliana Queiroz. "Produção e caracterização de quitosana imobilizada em substratos visando adsorção de ions metalicos." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267118.
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Orientador: Marisa Masumi BeppuDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
Made available in DSpace on 2018-08-15T00:01:01Z (GMT). No. of bitstreams: 1 Albarelli_JulianaQueiroz_M.pdf: 12079656 bytes, checksum: 4883a6fcc74937bc5e4be6b917ed0747 (MD5) Previous issue date: 2009
Resumo: A quitosana é um polímero natural muito estudado devido à sua boa capacidade adsorvente. A aplicação deste biopolímero para remoção de metais pesados tem sido estudada desde o início dos anos 1970 sendo que o número de trabalhos sobre este tema cresceu rapidamente desde então. No entanto, o uso da quitosana como adsorvente em maior escala enfrenta alguns obstáculos, devido à sua baixa resistência mecânica. Uma possível alternativa para melhorar aspectos mecânicos e que também contribui para uma melhor transferência de massa do adsorbato no adsorvente é a imobilização da quitosana em matrizes sólidas utilizando-se técnicas de recobrimento de partículas. Neste contexto, este trabalho visou investigar a imobilização da quitosana em substratos para a aplicação em sistemas de adsorção. Inicialmente foram testados como suporte para imobilização da quitosana vidro, polipropileno, borracha vulcanizada, porcelana e tecido de algodão. O substrato de vidro, utilizado na forma de esferas, apresentou melhor interação com a solução de recobrimento e características adequadas para aplicação em processos de adsorção. As esferas de vidro foram recobertas por diferentes métodos utilizando quitosana 2,5% (m/v) em solução de ácido acético 3% (v/v). O material recoberto foi utilizado em sistemas de adsorção em batelada e contínuo a fim de se analisar a capacidade de remoção de cobre pelo filme de quitosana. Dentre as diferentes técnicas de revestimento estudadas, o processo por "dip coating" obteve um revestimento homogêneo e apresentou boa aderência do filme ao substrato. A natureza da superfície a ser recoberta e a temperatura da solução de recobrimento foram variadas objetivando-se melhorar a fixação da camada de quitosana no suporte, sendo esta ultima variável a mais importante para as condições estudadas. As isotermas de adsorção indicaram um aumento na capacidade de adsorção com o aumento da temperatura na qual ocorre a adsorção. Os dados foram mais bem representados pela isoterma de Langmuir, indicando que o principal fenômeno de adsorção se assemelha a adsorção em monocamada. Observou-se que a capacidade máxima de adsorção encontrada em 25 º C foi semelhante a outros sistemas de adsorção de cobre utilizando quitosana relatados na literatura. Verificou-se um melhor ajuste para o modelo cinético de pseudo-segunda ordem, sugerindo que o fator limitante para a transferência de massa é a reação química. Os estudos de adsorção dinâmica usando as esferas recobertas em sistema de leito fixo demonstraram a possibilidade de seu uso com resultados promissores.
Abstract: Chitosan is a natural polymer largely studied because of its good adsorption capacity. The application of this biosorbent for heavy metal removal has been studied since early 1970s and the number of papers in this subject has grown quickly ever since. However, the use of this material in larger scale faces some barriers due to its low mechanical strength. A possible alternative to improve mechanical resistance and also enhance mass transfer is the immobilization of chitosan onto solid matrices using particle coating techniques. In this context, this study investigates the immobilization of chitosan onto solid supports and its application on adsorption systems. It was tested as support for chitosan immobilization glass, polypropylene, vulcanized rubber, porcelain and cotton. The glass support, used in bead form, has shown the best interaction with the coating solution and good characteristics for application in adsorption processes. Glass beads were coated by different methods using chitosan 2.5% w/v in acetic acid 3% v/v solution. The coated material was used in batch and continuous adsorption systems to analyze the copper removal capacity of the chitosan film. Among the different coating techniques studied, the dip coating procedure formed a homogeneous coating and presented an acceptable film adhesion to the substrate. Variables such as type of surface to be covered and temperature of the coating solution were analyzed on the fixation of the coated material on the substrate. The latter variable affected the most in the studied condition. Adsorption isotherms indicated an increase in the adsorption capacity along with the increase of adsorption temperature. The data were better fitted by Langmuir model, which indicates that the main phenomenon that occurred approaches to a monolayer-type adsorption. The maximum adsorption capacity was found at 25ºC and its value was similar to other copper adsorption systems reported in the literature. The mechanism of sorption showed a better fitting to the second order kinetic model, suggesting that the limiting factor to mass transfer is the chemical reaction. The dynamic adsorption studies using the coated beads in a fixed bed system demonstrated the possibility of its use with promising results.
Mestrado
Engenharia de Processos
Mestre em Engenharia Química
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Aleksandra, Šućurović. "Kinetika i mehanizam uklanjanja odabranih metala iz vode adsorpcijom na aminofunkcionalizovanom ugljeničnom nanomaterijalu." Phd thesis, Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu, 2017. https://www.cris.uns.ac.rs/record.jsf?recordId=104809&source=NDLTD&language=en.
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Predmet istraživanja ove doktorske disertacije bio je ispitivanje adsorpcionog ponašanja As(III) i odabranih metala (Cu(II), Cd(II), Pb(II), Cr(VI)) na amino- funkcionalizovanim višeslojnim ugljeničnim nanocevima, MWCNT-NH2 , na četiri odabrane pH vrednosti (3; 4,5; 6 i 11) i pri različitim sastavima vodenog rastvora (prisustvo hlorida, nitrata, sulfata i fosfata), a u cilju ispitivanja mogućnosti primene MWCNT-NH2 za uklanjanje arsena i jona metala iz vodenih rastvora u oblasti relativno niskih koncentracija (0,01-3 mg L -1 ). Fokus ove doktorske disertacijeje bio na utvrđivanju mehanizma procesa adsorpcije u ispitivanim uslovima. Adsorpciju arsena i metala na MWCNT-NH2 najbolje je opisao reakcioni model pseudo-drugog reda što znači da adsorpcija može biti pripisana uspostavljanju hemijskih interakcija između adsorbata i vezivnih grupa na površini adsorbenta. Modelovanje brzine Weber Morris-ovim difuzionim modelom ukazalo je na to da unutarčestična difuzija, iako sporiji korak od eksterne difuzije, nije jedini ograničavajući korak u procesu adsorpcije, već su za to odgovorne i interakcije ispitivanih jona sa vezivnim mestima na površini adsorbenta. U ravnotežnim uslovima, na različitim pH vrednostima, adsorpcija se mogla opisati Langmuir-ovim i Freundlich-ovim adsorpcionim modelima. Kapacitet i afinitet adsorbenta, kao i sam mehanizam adsorpcije, značajno su bili uslovljeni pH vrednošću rastvora, kako zbog karakteristika površine ispitivanog adsorbenta uslovljenih pH vrednošću, tako i zbog uticaja pH vrednosti rastvora na pojavne hemijske oblike u kojima se arsen i metali nalaze. Ispitivanje uticaja anjona pokazalo je da je prisustvo hlorida povećalo afinitet površine MWCNT-NH2 ka jonima arsena i svih metala u oblasti niskihkoncentracija, dok je prisustvo hlorida, nitrata, sulfata i fosfata pozitivno uticalo na afinitet površine (od 2 do 8 puta veći u odnosu na dejonizovanu vodu) MWCNT-NH2ka Cu(II) u oblasti viših koncentracija. Najmanji uticaj anjona na afinitet površine ka vezivanju metala primećen je kod hroma. Pretpostavljeni mehanizmi uklanjanja arsena i odabranih metala u prisustvu anjona ukljuĉuju reakcije građenja različitih vrsta spoljašnje- i unutrašnje-sfernih kompleksa, jonske izmene, kao i elektrostatičke interakcije koje se ostvaruju između pozitivno naelektrisane površine MWCNT-NH2 i anjona, na pH vrednostima manjim od 6,4, a koje menjaju afinitetpovršine ka jonima arsena i metala. Rezultati ove doktorske disertacije pokazuju da se ispitivani adsorbent, MWCNT-NH2 , može koristiti za uklanjanje arsena i teških metala iz vode u prisustvu različitih anjona i da, svojim adsorpcionim karakteristikama, može konkurisati komercijalnim i ekonomski pristupačnim adsorbentima.The subject of this doctoral thesis was the examination of the adsorption behaviour of As(III), and selected metals (Cu(II), Cd(II), Pb(II), Cr(VI)) on the amino-functionalized multiwalled carbon nanotubes, MWCNT-NH2, at four pH values (3, 4.5, 6, and 11) with different compositions of aqueous solutions (in the presence of chlorides, nitrates, sulphates and phosphates), in order to examine the possibilities of applying MWCNT-NH2 in removal of arsenic and metal ions from aqueous solutions in relatively low concentration (0,01- 3mg L-1). The focus of this doctoral thesis was to establish the mechanism of adsorption process in given conditions. Arsenic and metal adsorption on MWCNT-NH2 were best described with the pseudo-second order kinetic model, which assumes that adsorption can be attributed to the establishment of chemical reactions between the adsorbate, and the binding groups at the surface of adsorbent. The Weber - Morris diffusion model indicated that intercellular diffusion, although being a slower step than external diffusion, is not the only limiting step in the adsorption process, but also that the interactions of ions with the adsorbent surface binding sites, are responsible. In equilibrium, at different pH values, the adsorption could be described by the Langmuir and Freundlich adsorption models. The capacity and affinity of the adsorbent, and adsorption mechanism, were considerably determined by the pH value of the solution, either because of the characteristics of the surface of the investigated adsorbent depending on pH value, or the effect of the solution’s pH value on the chemical forms of arsenic and other metals. Investigation of the influence of the anion showed that the presence of chloride increased affinity of the surface of MWCNT-NH2 to arsenic ions and to all metals in low concentration ranges, while presence of chlorides, nitrates, sulphates and phosphates had a positive impact on the affinity of the surface (2 or 8 times greater than for deionized water) MWCNT-NH2 for Cu(II) in high concentration ranges. The smallest impact of anions to affinity of the surface to bond metals was noticed for chromium. The assumed mechanisms of removing arsenic and selected metals in the presence of anions include reactions of forming various kinds of outer- and inner-spheric complexes, ionic exchange, as well as electrostatic interaction which occur between positively charged surface of MWCNT-NH2 and anions, for pH < 6.4, and which change affinity of the surface towards arsenic and metal ions. Results of this doctoral thesis show that the investigated adsorbent, MWCNT-NH2, can be used for the removal of arsenic and heavy metals from water, in the presence of different anions, and that with its adsorbent characteristic it can compete with commercially, and economically more affordable adsorbents.
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Hendricks, Nicolette Rebecca. "The application of high capacity ion exchange adsorbent material, synthesized from fly ash and acid mine drainage, for the removal of heavy and trace metal from secondary Co-disposal process waters." Thesis, University of the Western Cape, 2005. http://hdl.handle.net/11394/1455.
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In South Africa, being the second largest global coal exporter, coal mining plays a pivotal role in the growth of our economy, as well as supplying our nation’s ever increasing electricity needs; while also accounting for more than 10% of the 20 x 109 m3 water used annually in the country. Coal mining may thus be classified as a large-scale water user; known to inevitably generate wastewater [acid mine drainage (AMD)] and other waste material, including fly ash (FA). Current and conventional AMD treatment technologies include precipitation–aggregation (coagulation/flocculation) – settling as hydroxides or insoluble salts. The process stream resulting from these precipitation processes is still highly saline, therefore has to undergo secondary treatment. The best available desalination techniques include reverse osmosis (RO), electro dialysis (ED), ion exchange and evaporation. All available treatment methods associated with raw AMD and its derived process stream fall prey to numerous drawbacks. The result is that treatment is just as costly as the actual coal extraction. In addition, remediation only slows the problem down, while also having a short lifespan. Research conducted into converting fly ash, an otherwise waste material, into a marketable commodity has shown that direct mixing of known ratios of FA with AMD to a pre-determined pH, erves a dual purpose: the two wastes (AMD and FA) could be neutralized and produced a much cleaner water (secondary co-disposal [FA/AMD]-process water), broadly comparable to the process water derived from precipitation-aggregation treated AMD. The collected post process solid residues on the other hand, could be used for production of high capacity ion exchange material (e.g. zeolite A, faujasite, zeolite P, etc.). The produced ion exchange material can subsequently be utilized for the attenuation of metal species in neutralized FA/AMDprocess waters.Magister Scientiae - MSc
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Satofuka, Hiroyuki. "Studies on heavy metal ion-binding peptides : Application for heavy metal ion detection and detoxification." 京都大学 (Kyoto University), 2002. http://hdl.handle.net/2433/149818.
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Löfgren, Rebecka. "Metal ion adsorption of highly mesoporous magnesium carbonate." Thesis, Uppsala universitet, Nanoteknologi och funktionella material, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-388827.
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In this project the adsorption ability of mesoporous magnesium carbonate (MMC) for copper (Cu), cobalt (Co), chromium (Cr) and arsenic (As) was evaluated. This was done by mixing MMC and dissolved metal (of different concentrations) and measuring the concentration of the solution before and after addition of MMC with Inductively coupled plasma optical emission spectroscopy. Besides MMC, “ordinary” magnesium carbonate (MgCO_3) was evaluated for comparison. Furthermore, the MMC was characterised with various instruments before and after adsorption of the metals. The adsorption experiments established that MMC was able to adsorb large amounts of Cu, Co and As while MgCO_3 was not. Moreover, it was discovered that both materials adsorbed equally large amounts of Cr. At higher concentrations of Cu and Co the uptake capacity of MMC suddenly dropped. However, for As, it was determined that MMC reached saturation at a concentration of ~22 mg/L. An adsorption experiment of a mixture of metals of 20 mg/L of each metal could not conclude anything about the selectivity of MMC, but the experiment revealed that MMC was able to adsorb all of Cu, Co and As rapidly at this concentration. The characterisation of MMC before adsorption revealed an amorphous structure and a high porosity. The structure of MMC after adsorption of Cu went from amorphous to crystalline and after adsorption of Co and As the structure also became crystalline, but of a lower degree than after adsorption of Cu. Furthermore, it was discovered that ion exchange also occurred along with adsorption.
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Rozycki, Torsten von. "Computational investigations of divalent heavy metal ion homeostasis." kostenfrei, 2009. http://nbn-resolving.de/urn:nbn:de:gbv:3:4-359.
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Ngule, Chrispus M. Jr. "In Vitro Adsorption of Heavy Metals Using Metal-Organic Frameworks." Youngstown State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1597664070125999.
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Lozenko, Sergii. "Heavy metal ion sensors based on organic microcavity lasers." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2011. http://tel.archives-ouvertes.fr/tel-00744846.
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Monitoring of environmental pollutants present at low concentrations requires creation of miniature, low-cost, and highly sensitive detectors that are capable to specifically identify target substances. In this thesis, a detection approach based on refractive index sensing with polymer micro-lasers is proposed and its application to the detection of heavy metal pollutants in water (mercury - Hg2+, cadmium - Cd2+ and lead - Pb2+) is studied. The resonance frequencies of the microcavity are highly sensitive to the refractive indices of the resonator surrounding: the resonances shift by a small amount when the surface refractive index changes, resulting from the interaction of the mode evanescent field with the surrounding medium. This permits label-free detection by coating the resonator with a suitable recognition species. The originality of this work lies in the utilization of active microcavities, or microlasers, created of the dye-doped polymers. Active microcavities offer an enhanced signal/noise ratio as compared to the passive ones and very narrow resonance peaks even at moderate quality factors (Q ≥- 6000). The choice of polymers as an active medium is connected with a number of advantages they offer: as opposite to semiconductors, polymers can be easily functionalized, integrated in microfluidic circuits and are cheaper in processing. Moreover, the use of porous polymer matrices may allow accumulation of analyte ions inside the microcavity and thus enhance the sensitivity. Two possible applications of microlasers are investigated in the thesis: refractive index variation sensing with non-functionalized cavities and heavy metal ion detection with functionalized cavities. In the first case, the sensitivity values have been obtained, comparable with the reported in literature for planar passive microresonators. In the second case, the experimental proofs of specific detection of mercury ions in liquid are presented. The ways of sensitivity improvement are discussed and verified and a foundation is layed for the creation of integrated Lab-on-Chip microfluidic biochemical detector.
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Steinbaugh, Gregory E. "Heavy metal Ion transport utilizing natural and synthetic ionophores." The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1189785736.
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Zvinowanda, CM, JO Okonkwo, PN Shabalala, and NM Agyei. "A novel adsorbent for heavy metal remediation in aqueous environments." International Journal of Environmental Science and Technology, 2009. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001474.
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Abstract
The objective of this study was to investigate the possibility of using maize tassel as an alternative
adsorbent for the removal of chromium (VI) and cadmium (II) ions from aqueous solutions. The effect of pH, solution
temperature, contact time, initial metal ion concentration and adsorbent dose on the adsorption of chromium (VI) and
cadmium (II) by tassel was investigated using batch methods. Adsorption for both chromium (VI) and cadmium (II) was
found to be highly pH dependent compared to the other parameters investigated. Obtained results gave an adsorption
capacity of 79.1 % for chromium (VI) at pH 2, exposure time of 1h at 25 ºC. Maximum capacity of cadmium of 88 %
was obtained in the pH range of 5-6 at 25 ºC after exposure time of 1 h. The adsorption capacities of tassel for both
chromium (VI) and cadmium (II) were found to be comparable to those of other commercial adsorbents currently in use
for the removal of heavy metals from aqueous wastes. These results have demonstrated the immense potential of maize
tassel as an alternative adsorbent for toxic metal ions remediation in polluted water and wastewater.
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Benavente, Martha. "Adsorption of Metallic Ions onto Chitosan : Equilibrium and Kinetic Studies." Licentiate thesis, Stockholm : Kemiteknik, Chemical and Engineering and Technology, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4746.
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PULS, ROBERT WILLIAM. "ADSORPTION OF HEAVY METALS ON SOIL CLAYS (KAOLINITE, CADMIUM, MONTMORILLONITE, ZINC)." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183889.
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Metal cation adsorption is the predominant chemical mechanism governing the attenuation of toxic metal movement in soils. Clay minerals are the primary adsorbent surfaces in soils due to their ubiquitous nature and large reactive surface area. This study examined the relative affinity of the metals cadmium, nickel and zinc for the clay minerals kaolinite and montmorillonite. The influence which different mineral adsorbents and different complexing ligands in solution have on the adsorption of metal ions was assessed using the Hard-Soft Acid-Base Principle as a theoretical framework for predicting the maximum extent of adsorption and rate of adsorption. The HSAB principle is that hard bases prefer to complex hard acids and soft bases prefer to complex soft acids. The hypothesis that initiated these investigations was that the hard-soft character of mineral surfaces is due to their surface functional groups and can be measured using metal cation adsorption selectivity experiments where pH and complex ion formation are controlled. When complex ion formation in aqueous solution was minimized (i.e. in Ca(ClO₄)₂), adsorption decreased in the order of decreasing softness, CD > Zn > Ni for both clay minerals. Montmorillonite behaved as a slightly harder Lewis base than kaolinite, sorbing the harder Ni and Zn ions to a greater extent than Cd, although both minerals behaved as soft Lewis bases. In the presence of chloride and sulfate ligands, adsorption sequences changed and reflected results from typical soil solution studies. In some cases the adsorption sequences can be explained using the HSAB principle together with computer speciation data and this approach merits further consideration and research. Adsorption over time and calculated adsorption rate constants were generally consistent with equilibrium selectivity data. Adsorption rates decreased in the order Cd > Zn > Ni in Ca(ClO₄)₂ for both clay minerals. The adsorption curves reflect a two-step adsorption process involving a rapid exchange-type reaction followed by a much slower adsorption involving diffusion into the crystal or alteration of the surface through the formation of a new solid phase involving the adsorbed ions.
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Jeong, Chang-Yoon. "Modelling metal competition for adsorption sites on humic acid." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389363.
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Alam, Tanvir E. "Metal Oxide Graphene Nanocomposites for Organic and Heavy Metal Remediation." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/3945.
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This thesis consists of two research problems in the water decontamination area. In the first work, the main focus is to understand the structure and photocatalytic activity of titanium dioxide with graphene (G-TiO2) which is synthesized by using sol-gel method. The photocatalytic activity of TiO2 is limited by the short electron hole pair recombination time. Graphene, with high specific surface area and unique electronic properties, can be used as a good support for TiO2 to enhance the photocatalytic activity. The obtained G-TiO2 photocatalysts has been characterized by X-Ray Diffraction (XRD), Raman Spectroscopy, Transmission Electron Microscopy (TEM), FTIR Spectroscopy and Ultraviolet visible (UV-vis) Spectroscopy. This prepared G-TiO2 nanocomposite exhibited excellent photocatalysis degradation on methyl orange (MO) under irradiation of simulated sunlight. Such enthralling photocatalyst may find substantial applications in various fields.
The primary objective of the second work is to understand the nanocomposite structure of SiO2 coated over graphene (G) nanoplatelets. An attempt has been made to synthesize G-SiO2 nanocomposite using sol-gel technique. The G-SiO2 nanocomposite is characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Raman spectroscopy, FTIR spectroscopy, and Electrochemical and Electrical measurement technique, respectively. In this work, G-SiO2 nanoparticles with the water containing salts of zinc is added, and allowed to settle in water. The ZnCl2
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concentration displays a whitish color solution which has turned to colorless within one or two hours of treatment with G-SiO2 nanocomposites. The presence of heavy metal is tested using electrochemical cyclic voltammetry (CV) technique. The CV measurement on the water treated with G-SiO2 has been tested for several days to understand the presence of heavy metals in water. Interestingly, the near complete separation has been observed by treating the heavy metal contaminated water sample for one to two days in presence of G-SiO2 nanoparticles. The redox potential observed for the heavy metal has been found to diminish as a function of treatment with respect to time, and no redox peak is observed after the treatment for four to five days. Further test using EDS measurement indicates that the heavy metal ions are observed within the G-SiO2 nanocomposite. The recovery of G-SiO2 nanocomposite is obtained by washing using deionized water. Our experimental finding indicates that the G-SiO2 nanocomposite could be exploited for potential heavy metals cleaning from waste or drinking water.
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Jayasinghe, Manori. "Heavy-metal-ion transport in nanoporous selective-membranes theory and experiment /." Cincinnati, Ohio : University of Cincinnati, 2007. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1186764159.
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Thesis (Ph. D.)--University of Cincinnati, 2007.Title from electronic thesis title page (viewed Oct. 8, 2007). Includes abstract. Keywords: gamma alumina membranes, heavy-metal-ion transport, uranyl, membrane functionalization, nanoporous membranes, steering molecular dynamics, free energy study, liquid-liquid interface, water/hexane interface, tri-butyl phosphate. Includes bibliographical references.
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JAYASINGHE, MANORI I. "HEAVY-METAL-ION TRANSPORT IN NANOPOROUS SELECTIVE-MEMBRANES: THEORY AND EXPERIMENT." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1186764159.
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Ma, Yiu Wa. "Fixed bed removal of heavy metal ions by chelating ion exchange." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491880.
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Column runs with varied operation conditions of flowrate, feed concentration and particle size have been conducted to observe the sorption of nickel, copper and zinc by the chelating resin. They all show a typical constant-pattern, steep curve in the first part of the breakthrough curve and the slope would dramatically reduce at a breakpoint such that it would take extremely long time to reach 100% breakthrough level. ~ The Modified Bed Depth Service Time (BDST) model incorporated with a timedependent bed capacity has been used together with the Empty Bed Residence Time (EBRT) model to analyze the fixed bed performance under different operating conditions. The Homogeneous Surface Diffusion Model (HSDM) and the Shrinking Core Diffusion . Model (SCDM) have been applied to- model the fixed bed performance. Due to the dramatic change in the slope, the first and second parts of the breakthrough curves need to be modeled separately. Comparing the two models, SCDM is more appropriate to explain the sorption of metal ions into the chelating resin. The research has suggested the existence of a Na-loaded outer shell and a H-loaded inner core in the chelating resin. When the moving boundary progresses from the outer shell into the inner core, there is a remarkable change in the ion exchange process, resulting in different kinetics. This explains the sharp change in the slope of the experimental breakthrough curves. A new version of SCDM has been developed to model the progression of the moving boundary inside the resin for the successive resin layers along the whole resin column so as to predict the column' s solid and liquid phase concentration profiles. The new SCDM has. the flexibility of varying the portion of the outer shell so that the behavior of resins with different resin Na contents can be predicted.
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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
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Pitcher, Sarah. "Investigation of heavy metal removal from motorway stormwater using inorganic ion exchange." Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/804873/.
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Karimanal, Kamalakannan Venkatasan. "Adsorption of saturated heavy metal vapors from combustion sources by condensation onto suspended sorbents /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
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Weber, L. A. (Lawrence Adna) 1907. "The permeability and adsorption capability of kaolinite and bentonite clays under heavy metal leaching /." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59904.
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Two soils, a kaolinite clay and a mixture of sand and sodium bentonite were used in this study to determine the effects of a heavy metal permeant on the materials' hydraulic conductivity and adsorption capability. A contaminant solution of lead nitrate was leached through the specimens. The permeability tests were repeated over a range of hydraulic gradients for several different concentrations of lead.The results from this study indicated that the hydraulic conductivity of the kaolinite clay was unaffected by permeation with the lead solution. The sand/bentonite mixture showed an increase in permeability of more than one order of magnitude, although this change was dependent on a high concentration of lead and particle migration.
For both soils, the majority of the lead was retained in the bottom third of the samples. Breakthrough of lead only occurred in the samples permeated with the most concentrated lead solutions.
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Tayab, Muhammad Rehan. "Environmental impact of heavy metal pollution in natural aquatic systems." Thesis, Brunel University, 1991. http://bura.brunel.ac.uk/handle/2438/5503.
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The distribution of heavy metals between soil and soil solutions is a key issue in evaluating the environmental impact of long term applications of heavy metals to land. Contamination of soils by heavy metals has been reported by many workers. Metal adsorption is affected by many factors, including soil pH, clay mineralogy, abundance of oxides and organic matter, soil composition and solution ionic strength. The pH is one of the many factors affecting mobility of heavy metals in soils and it is likely to be the most easily managed and the most significant. To provide the appropriate level of protection for aquatic life and other uses of the resource, it is important to be able to predict the environmental distribution of important metals on spatial and temporal scales and to do so with particular emphasis on the water column concentrations. Regulatory levels reflected in water quality criteria or standards are based on water column concentrations. Predicting water column concentrations requires a consideration of the interactions of water column contaminants with both bed sediments and suspended particulates as critical components in the assessment. The adsorption behaviour of cadmium, copper, lead and zinc onto soils is studied under the various geo-environmental conditions of pH, concentration of adsorbate and adsorbent, and solution compositions. Experiments were conducted to determine the equilibrium contact time of various adsorbates for adsorbent in different systems. Experiments were also conducted to check the efficiency of various acid-mixtures to extract heavy metal from soils into the aqueous phase. The adsorption behaviour of heavy metals onto soils was also studied from sea-water system. Soils are characterized in terms of the role of clay minerals to remove the metals from the solution phase, back-ground levels of metals, maximum adsorption capacity to adsorb various heavy metals from different adsorption systems, and type of surface sites present. The experimental data of metal adsorption is described by Langmuir adsorption model. The adsorption data are also expressed in terms of surface loading, surface acidity, adsorption density, and affinity of soils for heavy metals in different adsorption systems. Ecological implications of changes in physical and chemical conditions in aquatic systems on heavy metals uptake by soils are also discussed. This research covers the following areas: the environmental impact of heavy metal discharge into the aquatic systems, the study of the mobility patterns of different heavy metals as function of geo-environmental conditions, and determination of the pathways and the ultimate fate of heavy metals in the environment.
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Thomson, Bruce Winchester. "Heavy metal uptake on manganese oxide : coated filter sand obtained from the forehill water treatment plant, Peterhead, Aberdeenshire." Thesis, Robert Gordon University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289088.
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Sun, Xin. "Organofunctional silica mesostructures with improved accessibility and applications as heavy metal ion adsorbents." Diss., Connect to online resource - MSU authorized users, 2008.
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Kleinübing, Sirlei Jaiana. "Bioadsorção competitiva dos ions niquel e cobre em alginato e alga marinha Sargassum filipendula." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267115.
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Orientador: Meuris Gurgel Carlos da SilvaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: Estudos no campo da biotecnologia ambiental tem buscado encontrar materiais alternativos para o tratamento de efluentes industriais, dentre os quais se destacam as algas marinhas marrons. O alginato e o seu principal polissacarídeo e a presença dos ácidos manuronico (M) e guluronico (G) neste biopolimero esta diretamente relacionada a capacidade de bioadsorcao de íons metálicos. As propriedades de adsorção de diferentes espécies metálicas individuais vem sendo largamente estudadas, embora a maioria dos efluentes industriais contenha varias espécies metálicas em mistura. Este trabalho teve como objetivo investigar o fenômeno de bioadsorcao em sistemas simples e binário, constituídos dos íons Cu2+ e Ni2+, utilizando alginatos comerciais e alga marinha Sargassum filipendula como bioadsorventes. O estudo com alginatos comerciais visou auxiliar na compreensão dos mecanismos envolvidos no processo de bioadsorcao pelas algas marrons. Dois tipos de alginatos com diferentes relações M/G foram avaliados em sistemas monocomponentes. O alginato com menor relação M/G apresentou maior capacidade de bioadsorcao de ambos os íons metálicos. Seguiu-se então o estudo com a alga marinha Sargassum filipendula como bioadsorvente. Inicialmente, foi feita a extração do acido alginico e sua caracterização quanto a relação M/G. Em seguida, foi realizada a identificação dos grupos funcionais presentes na alga que poderiam estar envolvidos no processo de bioadsorcao. Verificou-se que os grupos carboxílicos e álcoois presentes no alginato, grupos sulfatos presentes na fucoidana, e grupos aminos nos aminoácidos, são responsáveis pelas ligações com estes íons. Para a obtenção dos dados de equilíbrio, foram realizados experimentos de remoção individual e da mistura dos íons Cu2+ e Ni2+ pela alga marinha Sargassum filipendula em coluna de leito fixo. Diferentes modelos foram aplicados para ajustar o equilíbrio e o modelo desenvolvido por Silva (2001) para simular a dinâmica de bioadsorcao. A bioadsorcao dos íons metálicos quando puros em solução apresentou capacidades adequadas tanto para o Cu2+ como para o Ni2+. Para a condição binária, o fenômeno de troca seqüencial foi observado, onde o íon Cu2+ desloca o Ni2+ anteriormente bioadsorvido. O modelo de Silva (2001) se ajustou aos dados experimentais obtidos tanto na condicao simples como na binária. Foram estudados, ainda, três ciclos de bioadsorção/dessorção, sendo verificado que a alga manteve suas características de bioadsorcao, assim como o efeito competitivo entre os íons durante os três ciclos avaliados.
Abstract: Environmental biotechnology studies have been conducted using alternative materials in order to eliminate heavy metal ions from industrial effluents. Brown algae are an attractive materials, due to their large availability and their reduced participation in the vital functions of marine ecosystems. The main structural polysaccharide of the brown algae is alginate, constituted of two uronic acids, mannuronic (M) e guluronic (G), and these groups are directly related to its bioadsorption capacity. The adsorption of different heavy metal ions in single systems has been investigated. However, in real systems it is more common to observe several ions in solution, which may interfere and compete for adsorption sites. The aim of this work was to study the bioadsorption of Cu2+ and Ni2+ ions on Sargassum filipendula seaweed and on commercial alginate (single and binary systems), in order to evaluate the competition of different metallic ions for the adsorption sites of bioadsorbents. Two types of alginates with different M / G ratio were evaluated in single component systems. Alginate with the lower M / G ratios showed a higher biosorption capacity of both metal ions. Next, a study with the seaweed Sargassum filipendula as biosorbent was performed. Initially, the alginic acid was extracted and its M / G ratio was characterized. The functional groups present in the algae that could be involved in the process of biosorption were identified. These results indicated that the alcohols and carboxylic groups present in alginate, sulphate groups present in fucoidan, and amino groups in amino acids, are responsible for binding these ions. To obtain equilibrium data, experiments were carried out to remove ions Cu2+ and Ni2+ individuales or in mixture by Sargassum filipendula seaweed in fixed bed column. Different equilibrium models were used to adjust the experimental data and the model developed by Silva (2001) was employed to simulate the dynamic of biosorption. The biosorption of pure ions in solution showed adequate capacity for Cu2+ and Ni2+. For the binary condition, the phenomenon of sequential exchange was observed, where the Cu2+ ion displaces the previously bioadsorbed Ni2+ ion. The mathematical model of Silva (2001) was able to describe satisfactorily the experimental data obtained for single and binary conditions. With regard to biosorption performance for sorption/desorption cycles, metal uptake remained practically unaltered as well as the competition effect between the ions during three successive cycles.
Doutorado
Engenharia de Processos
Doutor em Engenharia Química
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Yang, Cheng-Yu, and 楊政育. "Adsorption of Heavy Metal Ions ( Cu, Zn, Ni, Pb, ) by crosslinked metal ion-templated chitosan." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/56640797127369507350.
Full textAbstract:
碩士國立高雄師範大學
化學系
94
Chitosan is capable of adsorbing metal ions due to its amine and hydroxy groups, but chitosan is soluble in organic acids and inorganic acids. Crosslinking is used to improve the acid-resisting of chitosan. Moreover, crosslinking will lower the adsorbability of chitosan. In this research, we made the crosslinked metal ion-templated chitosan with two crosslinker of Glutaraldehyde, Epichlorohydrin and four metal ion of Cu2+、Zn2+、Ni2＋、 Pb2+, and observe the situation of adsorbing heavy metal ions such as Cu2+、Zn2+、Ni2＋and Pb2+ ions with it. In this research, (1) the GLA-crosslinked metal ion-templated chitosan : The adsorption capacity of Cu2+ is 35.51 mg/g for Cu(II)-templated chitosan and increase 54.8% compared with the non-templated chitosan. The adsorption capacity of Zn2+ is 15.97 mg/g for Zn(II)-templated chitosan and increase 42.08% compared with the non-templated chitosan. The adsorption capacity of Ni2+ is 65.38 mg/g for Ni(II)-templated chitosan and increase 428.17% compared with the non-templated chitosan; The adsorption capacity of Pb2+ is 100.12 mg/g for Pb(II)-templated chitosan and increase 42.09% compared with the non-templated chitosan. (2)the ECH-crosslinked metal ion-tempalted chitosan: The adsorption capacity of Cu2+ is 26.97 mg/g for Cu(II)-templated chitosan and increase 198.34% compared with the non- templated chitosan. The adsorption capacity of Zn2+ is 14.59 mg/g for Zn(II)-templated chitosan and increase 46.34% compared with the non- templated chitosan. The adsorption capacity of Ni2+ is 17.05 mg/g for Ni(II)- templated chitosan and increase144.62% compared with the non- templated chitosan. The adsorption capacity of Pb2+ is 61.49 mg/g for Pb(II)-templated chitosan and increase 17.66% compared with the non- templated chitosan. We found that the crosslinked metal ion-templated chitosan has higher adsorbtion capacity and selectivity than the crosslinked non-templated chitosan and that the GLA-crosslinked metal ion-templated chitosan has higher adsorption capacity than ECH- crosslinked metal ion-templated chitosa
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Wu, Ming Tsung, and 吳明宗. "Amino-grafted β-chitosan and its application on heavy metal ion adsorption." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/98585110763612174580.
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碩士萬能科技大學
材料科技研究所
99
Industrial effluent containing any heavy metals will cause seriously environmental pollutions and damages. Any attempts on removal of metal ions for contaminated water prior to discharging will win universal acceptance. Chitosan has a number of commercial and possible biomedical uses owing to its biocompatible, biodegradable and renewable properties, and was found to be one of excellent candidates for metal ion adsorbents. In order to enhance its adsorbing capability, β-chitosan was used as a precursor for further modification, by which the amino group on C2 of the chitosan can react with benzaldehyde under protection and thereby generates a Schiff base in the reaction system. It allows epichlorohydrin and triethylenetetramine to react with chitosan by means of grafting polymerization, and eventually, a crosslinked structure was formed. The structural changes, properties, and adsorbing capabilities of modified chitosans among these reaction sequences were systematically analyzed using FTIR, UV-VIS, XRD, EA, NMR, TGA, DSC, BET and SEM measurements. For the reaction of Schiff base formation, an ultimate reaction condition was obtained by using the orthogonal optimal method. It indicated that a feed composition containing chitosan of 1 g and benzaldehyde of 5ml can get optimal effect as performed a reaction under pH 7 at a reaction temperature of 60 oC for 3 h. It was found from the result that the capacity of modified chitosan for copper ion adsorption can be greatly promoted at pH 2 ~ pH 6, i.e., increased from 67.76mg/g to 117.60mg/g at a pH of 6. In addition to, the adsorptions on silver ions are higher than those of copper ions as compared under the same pH value, for instance, the silver adsorption at pH 6 is 151.20mg/g, and the copper adsorption 117.60mg/g. An important point to emphasize is the fact that the modified chitosan becomes more acid resistant as compare with the pristine one.
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Yang, Te-Chien, and 楊得謙. "Application of bacterial heavy metal ion binding proteins for silver resistance and adsorption." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/18326510462067964364.
Full textAbstract:
碩士國立中興大學
生命科學院碩士在職專班
97
Heavy metal pollution has posed one of the serious threat to human health, therefore, seeks an economy and effective method to clear the heavy metal pollution is the urgent matter.Bioremediation is the best method can clear heavy metal pollution completely and will not cause the second pollution. Because the bacterial heavy metal binding proteins can absorb the heavy metal ions, therefore we can use the biological characteristics to eliminate the heavy metal pollution in the soil or water. Take the SilE protein as the example, the SilE protein has played the key role in the resistant mechanism of silver resistant bacterium, therefore, the Ag+ adsorptive capacity of SilE protein will be closely linked to its silver resistance. Six strains were included in this project. E.coli strain J53 contains plasmid pMG101 which have silver resistance. There are nine open reading frames of the silver resistance determinant in the plasmid, including SilE protein. Two recombinant plasmids were constructed by cloning silE gene with or without signal sequence into pET21b vector, resulting SilE-SP and SilE-NSP respectively. For MerP protein, another two constructs were made by cloning MerP with signal sequence or B95P without signal sequence into pET21b vector. All recombinant plasmids were transformed to E.coli BL21 (DE3) strain. One control is with backbone pET21b in E.coli BL21 (DE3). Resistance tests in agar plate and in liquid medium were performed to detect the strength of resistance to Ag+. In disc assay, the strength was pMG101＞SilE-SP＞MerP＞pET21b＞SilE-NSP＞B95P and pMG101＞MerP＞SilE-SP＞pET21b＞SilE-NSP＞B95P for resistance test in liquid medium. Because both SilE and MerP protein can absorb heavy metal ions, adsobability experiment was also done to detect the Ag+ residue in the buffer. The results were 1.89 ± 0.026 mg/l for pMG101，1.92 ± 0.031 mg/l for MerP，1.93 ± 0.006 mg/l for pET21b，1.94 ± 0.021 mg/l for SilE-SP，1.94 ± 0.020 mg/l for SilE-NSP，and 2.10 ± 0.026 mg/l for B95P. In brief, the adsorbability to adsorb Ag+ is pMG101＞MerP＞pET21b＞SilE-SP≒SilE-NSP＞B95P. The results above showed that MerP protein can absorb Ag＋ and the efficiency is only less than pMG101（J53）, therefore, the next experiment was to observe the growth and detect the amount of the Ag＋ can be absorbed by the transgenic plant containing merP gene （P5 transgenic plant）. The host of bacterial merP gene is Arabidopsis. Furthermore, because MerP protein can absorb Hg+2, Ag+ and other heavy metals, the character of adsorption to heavy metal ions needs to be further investigated for the P5 transgenic plant. We found the differences for silver adsorption of P5 transgenic plant embedding in MS medium containing between Ag+ only and both Hg+2 and Ag+.The results indicated that the plant can absorb more Ag+ in the condition containing both Hg+2 and Ag+.
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Yu, Cheng-wei, and 游鎮蔚. "Adsorption of Heavy Metal Ions by Chemically Modified Barley Residual." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/66639835869203732545.
Full textAbstract:
碩士嘉南藥理科技大學
環境工程與科學系暨研究所
98
Barley residual modified with chemical methods into adsorbent, which was used to increase the adsorption capacity of heavy metals than bare barley residual. The solid and liquid waste from food processing plant could be solved in the same time. Waste reduction and reuse could be promoted and the sustainable utilization of overall environment. Four chemical modification methods were used to prepare 6 modified adsorbents. The adsorption capacity of heavy metal ions (Cu2+, Pb2+, and Zn2+) was characterized by pH, contact time, contact temperature and heavy metal ions. The adsorption efficiencies also described with isothermal adsorption, adsorption dynamic and adsorption kinetics models. The best adsorption capacity of Cu2+, Pb2+ and Zn2+ into bare and modified adsorbents were 383.2, 113.3, and 89.5 mg/g, respectively; the lowest adsorption capacity for Cu2+, Pb2+ and Zn2+ were 30.8, 24.7 and 17.7 mg/g, respectively; the optimum operation pH ranged between 4.5 ~ 7.0. 120 minutes was needed to reach equilibrium state of adsorption.The pseudo-second order rate equation was valid for the description of dynamic adsorption behavior of heavy metal ions (Cu2+, Pb2+, and Zn2+). The adsorption of Cu2+ into thiourea and 0.25mL formaldehyde modified barley residual was physical adsorption. The other adsorbents for Cu2+ belong to chemical ion exchange. The adsorption of Pb2 + into bare and 6 modified adsorbents was chemical ion exchange behaviour. Except the bare barley residual, thiourea modified barley residual, phosphoric acid modified barley residual, phosphoric acid and thiourea modified barley residual, thiourea and acetic acid modified barley residual, the isothermal adsorption of Zn2+ was chemical ion exchange behaviour.
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Chou, Ching-Wei, and 周經偉. "Adsorption of Heavy Metal Ions on Chitosan/Silica Nanocomposite Membranes." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/mvaabg.
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碩士國立宜蘭大學
化學工程與材料工程學系碩士班
102
The main purpose of this study is to discuss adsorption of heavy metal ions on chitosan/silica nanocomposite membranes. The 200 nm silica particles were prepared by sol-gel method of tetraethyl orthosilicate (TEOS) through the hydrolysis and condensation reaction. Silica was first modified using silane treated polystyrene-sulfonic acid-g-maleic acid (PSSA_MA) with two different coupling agents including 3-aminopropyl triethoxysilane (APTES) and 3-glycidoxypropyl trimethoxysilane (GPTMS). Modified silica solution was added to chitosan aqueous solution, and the mixture solution was fabricated to hybrid membranes. The adsorption of iron (III), copper (II) and chromium (III) ions onto silica, modified silica and chitosan/silica composite membranes has been investigated. The sorption experiments were carried out in batch mode to optimize various parameters viz., initial concentration, contact time, and pH that influence the sorption. According to the effect of pH results discussed, pH at 2 was selected as the optimum pH for iron ion adsorption, and pH at 5 for copper and chromium ions adsorption. It was shown that PSSA_MA grafted on silica could enhance the removal effect of metal ion. The adsorption isotherm data obey the Langmuir model. Kinetics experimental values did fit pretty well with the pseudo second order model in all investigated cases, which indicate that the adsorption behaviors are a monolayer chemical adsorption.
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Chung, Jui-Yin, and 鍾瑞嬰. "Adsorption Equilibria of Phosphate and Heavy Metal Ions onto Goethite." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/69908323048528198976.
Full textAbstract:
碩士元智大學
化學工程學系
91
Goethite [a-FeO·OH], a kind of hydrated iron(III) oxide, was often encountered on the tropical and subtropical areas, and was the most stable (hydro-) oxidation state in soil. This study investigated the adsorption equilibria of single heavy metal－copper(II), zinc(II), and phosphate, as well as the competitive adsorption equilibria of binary copper(II) zinc(II) as well as binary phosphate and copper(II) onto synthesized goethite. All experiments were carried out at different temperatures (15~35℃), initial adsorbate concentrations, and pH values. The ionic strength was maintained at 0.1 mol/L of NaNO3. The amounts of heavy metals adsorbed decreased with decreasing pH, but increased in the case of single phosphate. In addition, the amounts of both heavy metals and single phosphate adsorbed increased as temperature was increased. All adsorption processes were endothermic. At a given equilibrium pH, the adsorption isotherms of single phosphate and heavy metals could be well described by the Langmuir equation. In the binary─copper(II)/zinc(II) system, the amounts of znic(II) adsorbed was decreased. However, in the binary copper(II)/phosphate system, the amounts of copper(II) and phosphate adsorbed were enhanced.
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Lin, Kuan-wei, and 林冠維. "Applications of annulated mesoporous silica for adsorption of heavy metal ion and for purification of protein." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/94955453112891780065.
Full textAbstract:
碩士國立中央大學
化學學系
101
Two parts in this thesis: Part one: annular rings with controllable sizes are successfully created on the surface of COOH-functionalized mesoporous silica (namely, XC-CAR-10, where X represents the number of carbons in the diamines used) for the adsorption of metal ions. Macrocylic effect in our annulated mesoporous silica plays a vital role in enhancing its adsorption ability for meta ions. In particular, excellent adsorption ability and selectivity towards ~300 µg/mg of Pb2+ metal ion were achieved using 3C-CAR-10. 3C-CAR-10 contains suitable geometric sizes and the cavities offer the “best-fit” for the cations for the formation of host-guest complexes. Part two: in order to develop novel materials for protein purification, we performed annular mesoporous silica on immobilized metal affinity chromatography as a tool for protein purification. Because the annular mesoporous silica is an excellent metal ion adsorbent, e.g. Co2+ and Ni2+, the M2+-annulated materials complexes were applied for the assays of protein purification. Finally, annulated mesoporous silica showed higher binding capability of proteins with his-tags. Thus, it can open an auxiliary avenue in the development of a new resin for the protein purification process.
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Chung, Chun-Hung, and 鍾濬鴻. "Enhancement of Heavy Metal Ions Adsorption with Chemically Modified Lignocellulosic Substrate." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/13132252015126749913.
Full textAbstract:
碩士嘉南藥理科技大學
環境工程與科學系碩士班
96
The use of five chemical modification processes, including phosphorylation, sulfonation, sodium thiosulfate, citric acid,and formaldehyde modification, to modify the lignocellulosic substrate of Leucaena lucocephala into adsorbent which could actually enhance the removal efficiency of metal ions (Cd2+ and Pb2+) from aqueous solution. Parameters that may affect the metal ions adsorption efficiency including solution pH, contact time, kinds of metal ions, initial metal concentration, competition metal ions and reaction temperature were conducted. The best adsorption efficiencies of Cd2+ and Pb2+ with adsorbents at optimal operation condition were sequenced as phosphorylation (91.8 mg-Pb2+/g, 61.2 mg-Cd2+/g ), sulfonation(46.2 mg-Pb2+/g, 18.4 mg-Cd2+/g), citric acid (43.8 mg-Pb2+/g, 16.4 mg-Cd2+/g ), formaldehyde modification (41.0 mg-Pb2+/g, 19.2 mg-Cd2+/g), sodium thiosulfate(30.8 mg-Pb2+/g, 12.4 mg-Cd2+/g), and nonmodified adsorbents (16.8 mg-Pb2+/g, 10.4 mg-Cd2+/g). The adsorption capacities of Cd2+ and Pb2+ depended on solution pH. The maximum adsorbed capacity of both heavy metals happened at pH 6.5. The adsorption equilibrium reached after 60 minutes of contact time with batch kinetic studies of each metal ion and different adsorbents. The experimental isothermal equilibrium data were evaluated with Freundlich, Langmuir, and Dubinin–Radushkevich equation isotherm models to calculate the isothermal adsorprtion constants and to decide the adsorption behaviour being chemical or physical reaction. Three adsorption kinetic models, Pseudo first–order rate equation, Pseudo second–order rate equation, and Intraparticle diffusion equation, were used to evaluate the experimental data. Under the effects of reaction temperature, initial metal concentration and competition metal ions, Pseudo second–order rate equation model best fitted to experimental data. The thermodynamic parameters (enthalpy change, free energy change, and entropy change) for both metal ions adsorption into six adsorbents with increasing temperature from 15 to 60 ℃ indicated that the Pb2+ adsoption was exothermic and feasible, and the Cd2+ adsorption was endothermic and feasible. The competition of binary heavy metal ions into six kinds of adsorbents also studied. The binding strength of Pb2+ was stronger than Cd2+ and increased with the initial heavy metal ions concentration.
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Chang, Yung-T'ai, and 張永泰. "Activated Carbon Adsorption of Multicomponent Containing Heavy Metal Ions and Organics." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/62322544363757358614.
Full textAbstract:
碩士淡江大學
水資源及環境工程所
83
The characters of activated carbon adsorption of heavy metals (Cu2+,Cd2+) in a multicomponent system were studies is this experiment. The adsorption was affected by addition different conccentration, reactivity organics in pH=2. 5. The findings in this experiment can be used for extimate the better operation condititons in order to increasing the efficacy of water and wastewater treatment. This paper contains the isotherms experiment and rate kinetics experiment. In regard to isotherms adsorption experiment, the results comply with Freundlich adsorption theory. The multicomponent system, metals: 200~500 mg/L, organics: 0~2000 mg/L, the 1/n and K which addition phenol are -0.3605~0.3160, 34.04~978.6 respectively; and addition glutamic acid are -0.4094~.02106, 22.4 0~75.86. It is founded that 1/n value are small, and no apparrent relationship with organics concentration, but K was increasing with organics concentration except Cu2+/ glutamic acid system. The rate models were estimated after data analysis. The model is C(t)=A0+A1*exp(-k1t)+A2* exp(-k2t) which represent paralle realtions (simultaneously) occur at different period. The rate constants in thhe Kinetic model. The k1 value range are 3.321~0.01994, which decrease with orgamics concentration increasing except Cu2+/phenol system. In addition to metalions and organics adsorption onto activated carbon. It is founded the rate of adsorption for organics is more than metalions. Glutamic acid has very strong chelating ability with metal ions, the chelating can even happend between glutamic acid and metal ions which were adsorption on activated carbon. The K, 1/n, k1, k2, of Cu2+/glutamic acid system differ from other systems due to the chelating complex was formed.
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Jiang, Shun-Chou, and 江順舟. "Synthesis of self-assembled fish scale collagen/tannin nanoparticles and their application in heavy metal ion adsorption." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/37560160161384239851.
Full textAbstract:
碩士明志科技大學
化學工程研究所
101
This fish scale collagen/tannic acid nanoparticles are formed by self-assembly of collagen and polyphenols, which are used to adsorption of heavy metal ions. The average size of synthetic nanoparticles is 100 ~ 500 nm. FTIR shows a free O-H stretching vibration of tannic acid occurs in the range 3338 cm-1, but the O-H group of the nanoparticles is involved in a hydrogen bond, its position is shifted to lower frequency, usually 3230 cm-1. The characterization of nanoparticles is investigated by XRD, TEM, DLS and DSC. The present study aims to explore the adsorption capacities, kinetics and thermodynamics of Cu(II) and Ni(II) ion from aqueous solution onto fabricated fish scale collagen/tannic acid nanoparticles. The maximum capacity for the adsorption of Cu(II) and Ni(II) ion onto nanoparticles, deduced from the use of the Langmuir isotherm equation, was 123 and 136 mg/g respectively. The experimental data of Cu(II) and Ni(II) ion adsorption fitted the pseudo-second order kinetic model well, indicating that chemical sorption is the rate-limiting step. The negative Gibbs free energy of adsorption indicated a spontaneous adsorption, while the positive enthalpy change indicated an endothermic adsorption process. Keywords: fish scale collagen; tannic acid; self-assembly; nanoparticles; adsorption
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Chang, Ju-Szu, and 張如斯. "The exploration of morphology and heavy metal-ion adsorption of electrospun nanofibers form hydrogel copolymers blending with algae." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/s5jtaw.
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碩士國立臺北科技大學
有機高分子研究所
102
The development of technology to bring increasingly severe negative impact on the environment, along with industrial and commercial development, emissions of waste water are also increasingly proliferated. In this study, given the many experimental sewage waste generated in institutions, acid waste containing organic solvents and heavy metals and other ingredients, if an overflow occurs upset when there is an immediate risk of harm, to be covered by the chemisorption of cotton acid containing heavy metals, alkaline liquid, proper follow-up treatment after adsorption to do to improve the quality of the environment. In this study, electrospinning and cross-linking of two processing technology, successfully prepared a series of Copolymer Poly (HEMA-co-MNA) ( HEMA with NMA segment containing different proportions ) electrospun nanofibers. Explore processed into parameters (polymer concentration, process flow rates, the use of solvents), and cross-linked changes in the proportions of the different segments of its nano- fiber morphology. SEM observation using different crosslinking conditions under which the water of the changes in fiber morphology found high levels NMA (10: 1 and 10 : 3) large degree of crosslinking , the crosslinked HEMA can not return to the fiber was dissolved in water , sustain a cylindrical fiber structure . Blending and use of algae in Poly (HEMA-co-MNA) copolymers, the use of a polymer prepared by electrospinning nanofibers containing algae, the study of heavy metal adsorption behavior. In the ICP-OES spectrometer tests, found to contain algae nano fibers with high specific surface area, within 10 minutes adsorption trend, and can quickly reach saturation adsorption within 2 hours, remove excellent efficiency of heavy metals. Algae changed its adsorption characteristics of heavy metals Pb, Cd, Ni, and environmental factors (initial pH, time, initial concentration of heavy metals), etc., will have a different impact absorption. Therefore, in this study the preparation of polymer nanofibers containing algae, not only with the biological adsorption principle to reduce environmental pollution adsorption of heavy metal waste, also showed rapid adsorption of heavy metals in the waste of performance, the future will be made of acid, alkali environmental chemisorption cotton, used in the related fields.
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Lee, Hsiu Wen, and 李修彣. "The adsorption of heavy metal ions on Polypyrrole added nanofibrous polymeric membranes." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/48609147981361417777.
Full textAbstract:
碩士長庚大學
機械工程學系
101
In this study we developed polypyrrole added electrospun nano- fibrous polyethersulfone nanofibrous membranes for the removal of heavy metal ions.Polypyrrole and polyethersulfone dissolved in N-methyl-2-pyrrolidone (NMP) were electrospun into nanofibrous membranes via an electrospinning process. The morphology of as-spun polypyrrole/polyethersulfone nanofibers was examined by scanning electron microscopy. The average diameter of electrospun nanofibers ranged from 410 nm to 540 nm. The adsorption capability of nanofibrous polypyrrole/polyethersulfone membranes was measured and compared with that of bulkpolypyrrole. The influence of various process conditions on adsorption efficiency was also examined. The experimental results suggested that the electrospun nanofibrous membranes exhibit good Ag (I) ion uptake capabilities. The metal uptake of nanofibrous membranes increased with the initial metal ion concentrations and the pH value, while decreased with the temperature and the filtering rate of the solutions. Furthermore, the electrospun membrane could be reused after the recovery process. The empirical results in this study suggested that electrospun polypyrrole/polyethersulfone nanofibrous membranes can be a good candidate for the removal of heavy metal ions.
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YUN, CHAO PEI, and 趙珮云. "Adsorption of heavy metal ions by a chelating resin containing cysteine groups." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/37512373227600900030.
Full textAbstract:
碩士南台科技大學
化學工程與材枓工程系
96
A chelating resin, crosslinked poly(glycidyl methacrylate-cysteine) (PCYS), was synthesized by anchoring sodium cysteine to crosslinked poly(glycidyl methacrylate) for the recovery of Ag+、Cu2+ and Cd2+ from aqueous solutions. The resin was characterized by Fourier transform infrared spectroscopy, scanning electron microscope. In non-competitive conditions, the adsorptions tended toward equilibrium at 60 min and the equilibrium adsorption capacities were 1.88、1.09 and 0.89 mmol/g PCYS for Ag+、Cu2+ and Cd2+, respectively. The adsorption isotherms of the metal ions by PCYS followed the Freundlich isotherm. Except pH ≥ 3.0, the adsorption capacity of each metal ion decreased with lowering of solution pH. When the pH of Cu2+/Cd2+ mixture was 2 , the competitive adsorption tests confirmed this resin had good adsorption selectivity for Cu2+ with the coexistence of Cd2+. When the pH of Ag+/Cu2+ and Ag+/Cd2+ mixture was 1.5 and 2.5, the competitive adsorption tests confirmed this resin had good adsorption selectivity for Ag+ with the coexistence of Cu2+ or Cd2+.
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Liu, Sheng-Chang, and 劉昇昌. "Adsorption of Heavy Metal Ions (Cu,Pb,Zn) On Chitosan Crosslinked with Epichlorohydrin." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/27342832225466042597.
Full textAbstract:
碩士國立高雄師範大學
化學系
93
Adsorption of Heavy Metal Ions (Cu,Pb,Zn) On Chitosan Crosslinked with Epichlorohydrin Sheng-chang Liu Abstract Chitosan is capable of chelating metal ions due to its amine and hydroxy groups, but it is a pity that chitosan is soluble in organic acids and low pH inorganic acids . In this research, raw chitosan flakes were crosslinked with epichlorohydrin in order to obtain sorbents insoluble in aqueous acid solutions and capable of adsorbing heavy metal ions such as Cu2+、Pb2+、Zn2+ ions. We had two goals in this research. First, the best pH values and molar ratio in crosslinking chitosan with epichlorohydrin were studied. Second, the adsorption conditions and maximum adsorption capacity of chitosan and corsslinked chitosan were studied. We found that the best pH values in the preparation of chitosan crosslinked with epichlorohydrin(ECH-Chitosan) was between pH 7 and 9 , and the molar ratio of ECH to chitosan was 3 or lower. ECH-Chitosan which had a particle size between 125μm and 500μm were not soluble in 5% acetic acid. Therelore, ECH-Chitosan beads were better than chitosan . In the adsorption of metal ions, we found that the maximum adsorption capacity of Cu2+ is 35.46mg/g for ECH-Chitosan and 37.88mg/g for chitosan ; the maximum adsorption capacity of Pb2+ is 34.13mg/g for ECH-Chitosan and 13.05mg/g for chitosan ; the maximum adsorption capacity of Zn2+ is 10.21mg/g for ECH-Chitosan and 10.32mg/g for chitosan .
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Tsai, Cheng-Kuo, and 蔡正國. "A Study of Adsorption of Dissolved Heavy Metal Ions by Composite Carbon Nanotubes." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/92212031270465937465.
Full textAbstract:
碩士國立雲林科技大學
環境與安全工程系碩士班
93
The Study of Adsorption of Heavy Metals from aqueous Solution by Composite Carbon Nanotubes Student: Cheng-Kuo Tsai Advisor: Dr. Jao-Jia Horng Institute of safety Health and Environmental Engineering National Yunlin University of Science and Technology ABSTRACT Carbon Nanotubes (CNTs) were grown on alumina oxide (α- Al2O3 ) after deposited Fe-Ni nanoparticles by chemical vapor deposition method to form CNT/Fe-Ni/ Al2O3 composite particles. Composite particles would be fabricated at low price, easy handling and had higher adsorption capacities of Pb+2, Cu+2 and Cd+2 than these of active carbon powders (PAC) and merchant CNTs. The composite CNTs were at sizes of micrometer length and with tube diameters of 80-100 nm. The sinking tests showed that merchant CNTs would aggregate fast while composite particles could disperse in solution to enhance mixing efficiency. The experimental results revealed that the composite particles were good adsorbent with capacities of Pb2+ 67.11 mg/g 、Cu2+ 26.59 mg/g、Cd2+ 8.89 mg/g, respectively. In this study the adsorption capacities of Pb+2, Cu+2 and Cd+2 were regressed by three adsorption models and Langmuir isotherm model showed good fit. The multi-layers adsorption (BET) was not accepted. The kinetic mechanism of adsorption by composite particles was found to be second order. The adsorption efficiency of 40 mg/l Pb2+、Cu2+ could reach 80% at 0.2 g dosage. The affinity order of competitive adsorption of three metal ions onto active carbon powders, merchant CNTs and composite particles were the same of Pb+2> Cu+2> Cd+2. The recovery of composite particles could still reach 90 % by 0.5 N nitrite even after six adsorption/regenerate cycles.