Bentonite as a Natural Adsorbent for the Sorption of Iron from the Ground Water Exploited from Aswan Area, Egypt |
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| Authors: | Gharib M Taha Kamal Abou Elmagd |
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| Institution: | Gharib M. Taha;, corresponding author (Chemistry Department, Aswan Faculty of Science, South Valley University, Aswan 81528, Egypt;), is a lecturer of analytical and environmental chemistry at the South Valley University of Aswan, Egypt. He has an M.S. from Assiut Univerisyt and a Ph.D. from South Valley University. Kamal Abou Elmagd;(Geology Department, Aswan Faculty of Science, South Valley University, Aswan 81528, Egypt;) is a lecturer of sedimentology at the South Valley University of Aswan, Egypt. He has an M.S. from Assuit University and a Ph.D. from South Valley University. |
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| Abstract: | Sorption of dissolved Fe2+ on bentonite was studied using a batch technique. The distribution coefficient, Kd , was evaluated for a bentonite-iron system as a function of contact time, pH, sorbent and sorbate concentrations, and temperature. Sorption results were interpreted in terms of Freundlich's and Langmuir's equations. Thermodynamic parameters for the sorption system were determined at three temperatures: 298°, 308°, and 318°K. The values of ΔH°(-4.0 kjmol?1) and ΔG°(-2.46 Kjmol?1) at 298°K (25°C) suggest that sorption of iron on bentonite is an exothermic and a spontaneous process. The ΔG° value became less negative at higher temperatures and, therefore, less iron was sorbed at higher temperatures. The desorption studies with 0.01 M CaCl2 and deionized water at iron loading on bentonite showed that more than 90 wt% of the iron is irreversibly sorbed, probably due to the fixation of the iron by isomorphous replacement in the crystal lattice of the sorbent. |
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