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Bentonite as a Natural Adsorbent for the Sorption of Iron from the Ground Water Exploited from Aswan Area, Egypt
Author(s) -
Taha Gharib M.,
Elmagd Kamal Abou
Publication year - 2004
Publication title -
groundwater monitoring and remediation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 47
eISSN - 1745-6592
pISSN - 1069-3629
DOI - 10.1111/j.1745-6592.2004.tb00703.x
Subject(s) - sorption , bentonite , sorbent , desorption , freundlich equation , chemistry , adsorption , langmuir , exothermic process , partition coefficient , inorganic chemistry , nuclear chemistry , chemical engineering , chromatography , organic chemistry , engineering
Sorption of dissolved Fe 2+ on bentonite was studied using a batch technique. The distribution coefficient, K d , 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 CaCl 2 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.