Evaluation of heavy metal removal from aqueous solution onto scolecite

Bosso, Sergio Tagliaferri; Enzweiler, Jacinta

doi:10.1016/s0043-1354(02)00208-7

Cited by 117 publications

(55 citation statements)

References 20 publications

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“…Quanto à recuperação do Pb 2+ utilizando soluções contendo Na + , vários autores confirmam a eficiência do tratamento: SHINZATO et al (inédi-to) verificaram eficiência de 94% na recuperação de Pb 2+ pela mordenita e BOSSO et al (2002) obtiveram 85% na zeólita escolecita.…”

Section: Capacidade De Regeneração Das Zeólitasunclassified

Remoção de metais pesados em solução por zeólitas naturais: revisão crítica

Shinzato

2007

Rev. Inst. Geol.

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RESUMONesta síntese são discutidos os resultados de trabalhos publicados nos últimos anos referentes à aplicação das zeólitas naturais na remoção de metais pesados em solução. A seqüência de seletividade iônica, bem como os parâmetros associados à eficiên-cia de adsorção e capacidade de troca catiônica (CTC), estão inteiramente relacionados à estrutura cristalina das zeólitas e às características químicas dos íons encontrados em solução. Cabe ressaltar que, algumas variáveis externas como temperatura, pH e concentração iônica inicial podem interferir no processo de remoção de metais, assim como na seqüência de seletividade iônica. De forma geral, íons com menor energia de hidratação possuem maior preferência pelos sítios de troca disponíveis nas estruturas das zeólitas. A eficiência de remoção de íons de maior energia de hidratação, por sua vez, pode ser controlada pela sua concentração na solução: quanto menor, melhor. Verifica-se, portanto, que as zeólitas naturais possuem grande potencial de aplicação em tratamentos de efluentes contaminados com metais pesados.Palavras-chave: zeólitas naturais, adsorção, troca iônica, metais pesados. ABSTRACTRecent work on the application of natural zeolites to the removal of heavy metals in solution is discussed. Ionic selectivity sequences of natural zeolites, as well as parameters associated with their efficiency of adsorption and ionic exchange, are closely related to their crystal structure and the chemical characteristics of the ions in solution. It is noteworthy that some external variables such as temperature, pH and initial ion concentration can interfere in the process of removal of heavy metals in solution, as well as in the sequence of ionic selectivity. In general, ions with low energy of hydration have greater preference for available charged exchange sites within the zeolite framework. The efficiency of removal of ions with higher energy of hydration, in turn, can be controlled by its solution concentration: the less concentrated the better. It is evident, therefore, that natural zeolites have a great potential in the treatment of effluents contaminated by heavy metals.

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Section: Capacidade De Regeneração Das Zeólitasunclassified

Remoção de metais pesados em solução por zeólitas naturais: revisão crítica

Shinzato

2007

Rev. Inst. Geol.

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“…At very low pH, the number of H3O + ions exceeds that of metal ions by several times and the metal ions can hardly compete with H3O + ions for the binding sites on the clay adsorbents and thus, electrostatic repulsion occurred between the metal ions (M 2+ ) and the edge groups with positive charge (SiOH2 + ) on the surface as follows: (Bosso and Enzweiler, 2002). This happens at lower pH (6.0) for Cu(II) (Nuhoglu and Oguz, 2003), while the adsorption could be safely carried out to pH (9.0) for Cd(II) (Mathialagan and Viraraghavan, 2002).…”

Section: The Effect Of Solution Phmentioning

confidence: 99%

Adsorption of cadmium and copper onto natural clay: isotherm, kinetic and thermodynamic studies

2018

Global NEST Journal

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Clay of the Middle Atlas Mountains region, Morocco, was used to investigate the removal of heavy metals ions (Cadmium and Copper) from aqueous solutions with respect to several experimental conditions including pH, contact time, initial solute concentrations, temperature and ionic strength. Kinetic study revealed that metal ions uptake was fast with 90% or more of the adsorption occurring within first 30 min of contact time. Adsorption rate increased with the increasing initial metal ions concentrations and the sorption rate was well fitted by the pseudo-second-order rate model. The data according to mass transfer and intraparticle diffusion models confirmed diffusion of solutes inside the clay particles as the ratecontrolling step and more important for the adsorption rate than the external mass transfer.The suitability of the adsorbent was tested by fitting the adsorption data with Langmuir and Freundlich isotherm models. Equilibrium and kinetic adsorption data showed that clay displays a high selectivity with an affinity order of Cd > Cu. Thermodynamic parameters including the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes indicated that the present adsorption process was feasible and endothermic in the temperature range of 25-45 °C.

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“…Acidic conditions, the clinoptilolite mineral surface will be completely covered with H 3 O 1 ions and the Ni 21 ions cannot compete with them for ionexchange sites. However, with increasing pH, the competition from the hydrogen ions decreases, and the positively charged Ni 21 ions can be exchanged with exchangeable cations and can also be adsorbed at the negatively charged sites on the clinoptilolite [6,28,36].…”

Section: Effect Of Initial Phmentioning

confidence: 99%

Ni²⁺ removal from aqueous solutions using conditioned clinoptilolites: Kinetic and isotherm studies

Çoruh

Ergun

2009

Env Prog and Sustain Energy

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The aim of this study is to investigate the effects of conditioning with NaCl and HCl solutions on removal of Ni 21 ions from aqueous solutions using natural clinoptilolite. Batch studies were performed to evaluate the effects of various parameters such as chemically conditioning, adsorbent amount, contact time, initial pH of the solution, mixing temperature, and initial metal ions. The results clearly showed that the conditioning improved both the exchange capacity and the removal efficiency. Langmuir, Freundlich, Temkin, and Dubinin-Kaganer-Radushkevich (DKR) isotherm models were adopted to describe the adsorption isotherms. Adsorption isotherms of Ni 21 ions could be best modeled by Langmuir equation. Three simplified models including pseudo-second-order, intraparticle diffusion and Elovich were used to test the adsorption kinetics. These results indicate a significant potential for the natural and conditioned clinoptilolites as an adsorbent/ionexchange material for heavy metal removal.

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Evaluation of heavy metal removal from aqueous solution onto scolecite

Cited by 117 publications

References 20 publications

Remoção de metais pesados em solução por zeólitas naturais: revisão crítica

Remoção de metais pesados em solução por zeólitas naturais: revisão crítica

Adsorption of cadmium and copper onto natural clay: isotherm, kinetic and thermodynamic studies

Ni²⁺ removal from aqueous solutions using conditioned clinoptilolites: Kinetic and isotherm studies

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Evaluation of heavy metal removal from aqueous solution onto scolecite

Cited by 117 publications

References 20 publications

Remoção de metais pesados em solução por zeólitas naturais: revisão crítica

Remoção de metais pesados em solução por zeólitas naturais: revisão crítica

Adsorption of cadmium and copper onto natural clay: isotherm, kinetic and thermodynamic studies

Ni2+ removal from aqueous solutions using conditioned clinoptilolites: Kinetic and isotherm studies

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Ni²⁺ removal from aqueous solutions using conditioned clinoptilolites: Kinetic and isotherm studies