Adsorption Characteristics of Zinc (Zn2+) from Aqueous Solution by Natural Bentonite and Kaolin Clay Minerals: A Comparative Study

Clay minerals are one of the potential good adsorbent alternatives to activated carbon because of their large surface area and high cation exchange capacity. In this work the adsorptive properties of natural bentonite and kaolin clay minerals in the removal of zinc (Zn2+) from aqueous solution have...

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Main Authors: Sen, Tushar, Khoo, C.
Format: Journal Article
Published: Scientific Research Publishing, Inc. 2013
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/20965
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author Sen, Tushar
Khoo, C.
author_facet Sen, Tushar
Khoo, C.
author_sort Sen, Tushar
building Curtin Institutional Repository
collection Online Access
description Clay minerals are one of the potential good adsorbent alternatives to activated carbon because of their large surface area and high cation exchange capacity. In this work the adsorptive properties of natural bentonite and kaolin clay minerals in the removal of zinc (Zn2+) from aqueous solution have been studied by laboratory batch adsorption kinetic and equilibrium experiments. The result shows that the amount of adsorption of zinc metal ion increases with initial metal ion concentration, contact time, but decreases with the amount of adsorbent and temperature of the system for both the adsorbents. Kinetic experiments clearly indicate that adsorption of zinc metal ion (Zn2+) on bentonite and kaolin is a two-step process: a very rapid adsorption of zinc metal ion to the external surface is followed by possible slow decreasing intraparticle diffusion in the interior of the adsorbent. This has also been confirmed by an intraparticle diffusion model. The equilibrium adsorption results are fitted better with the Langmuir isotherm compared to the Freundlich model. The value of separation factor, RL from Langmuir equation give an indication of favourable adsorption. Finally from thermodynamic studies, it has been found that the adsorption process is exothermic due to negative deltaG0 accompanied by decrease in entropy change and Gibbs free energy change (deltaG0). Overall bentonite is a better adsorbent than kaolin in the removal of Zn2+ from its aqueous solution.
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spelling curtin-20.500.11937-209652017-09-13T13:47:28Z Adsorption Characteristics of Zinc (Zn2+) from Aqueous Solution by Natural Bentonite and Kaolin Clay Minerals: A Comparative Study Sen, Tushar Khoo, C. Metal Ion Adsorption Kinetics Clay Minerals Isotherms Clay minerals are one of the potential good adsorbent alternatives to activated carbon because of their large surface area and high cation exchange capacity. In this work the adsorptive properties of natural bentonite and kaolin clay minerals in the removal of zinc (Zn2+) from aqueous solution have been studied by laboratory batch adsorption kinetic and equilibrium experiments. The result shows that the amount of adsorption of zinc metal ion increases with initial metal ion concentration, contact time, but decreases with the amount of adsorbent and temperature of the system for both the adsorbents. Kinetic experiments clearly indicate that adsorption of zinc metal ion (Zn2+) on bentonite and kaolin is a two-step process: a very rapid adsorption of zinc metal ion to the external surface is followed by possible slow decreasing intraparticle diffusion in the interior of the adsorbent. This has also been confirmed by an intraparticle diffusion model. The equilibrium adsorption results are fitted better with the Langmuir isotherm compared to the Freundlich model. The value of separation factor, RL from Langmuir equation give an indication of favourable adsorption. Finally from thermodynamic studies, it has been found that the adsorption process is exothermic due to negative deltaG0 accompanied by decrease in entropy change and Gibbs free energy change (deltaG0). Overall bentonite is a better adsorbent than kaolin in the removal of Zn2+ from its aqueous solution. 2013 Journal Article http://hdl.handle.net/20.500.11937/20965 10.4236/cweee.2013.23B001 Scientific Research Publishing, Inc. fulltext
spellingShingle Metal Ion Adsorption
Kinetics
Clay Minerals
Isotherms
Sen, Tushar
Khoo, C.
Adsorption Characteristics of Zinc (Zn2+) from Aqueous Solution by Natural Bentonite and Kaolin Clay Minerals: A Comparative Study
title Adsorption Characteristics of Zinc (Zn2+) from Aqueous Solution by Natural Bentonite and Kaolin Clay Minerals: A Comparative Study
title_full Adsorption Characteristics of Zinc (Zn2+) from Aqueous Solution by Natural Bentonite and Kaolin Clay Minerals: A Comparative Study
title_fullStr Adsorption Characteristics of Zinc (Zn2+) from Aqueous Solution by Natural Bentonite and Kaolin Clay Minerals: A Comparative Study
title_full_unstemmed Adsorption Characteristics of Zinc (Zn2+) from Aqueous Solution by Natural Bentonite and Kaolin Clay Minerals: A Comparative Study
title_short Adsorption Characteristics of Zinc (Zn2+) from Aqueous Solution by Natural Bentonite and Kaolin Clay Minerals: A Comparative Study
title_sort adsorption characteristics of zinc (zn2+) from aqueous solution by natural bentonite and kaolin clay minerals: a comparative study
topic Metal Ion Adsorption
Kinetics
Clay Minerals
Isotherms
url http://hdl.handle.net/20.500.11937/20965