Synthesis, Characterization and Adsorption Performance Analysis of
Polymer Treated Egyptian Clays
In view of pressing environmental impacts on soil earth and water it deemed necessary to develop and optimize appropriate low cost solutions for mitigating environmental pollution taking into consideration the current situation of industrial development and associated heavy metals pollution. Thus, this work has aimed at removal of specific heavy metals via treated and modified Egyptian clays (kaolin and bentonite). Both types comprising of bentonite and kaolin have been treated and modified by acids, alkali and polymer modification. Treated Egyptian clays have been characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM). Moreover, the prepared adsorbents have been tested for the removal of some heavy metals (Co2+, Cd2+, Cr3+, Cr6+ and Ni2+). Kaolin treated using oxalic acid showed slightly higher adsorption capacity (13.5, 16, 10 and 9.8 mg/g) than alkali treated kaolin (11.9, 16, 9.8 and 8.9 mg/g) while, the untreated kaolin adsorption capacity approached 8, 8, 6 and 6.7 mg/g for Co2+, Cd2+, Cr 3+ and Ni2+, respectively. Isotherm investigations revealed that the maximum adsorption capacities of Co2+and Cd2+ using acid, alkali treated and untreated kaolin were 25, 22.5 and 7.8 mg/g, respectively for cobalt. The corresponding values for cadmium were 23.8, 20.2 and 8.9 mg/g, respectively. An improvement has been attained via coating of kaolin ix with polacrylonitrile grafted cellulose whereas, the adsorption capacities of (Co2+, Cd2+, Cr3+ and Ni2+) approached (20.1, 28.1, 16.4and 19.8 mg/g ) as compared with the untreated kaolin which manifests the practical significance of this type of kaolin. Finally, rather significant improvement has been also achieved using bentonite coated chitosan as manifested by its ability to adsorb Cr 6+ (166 mg/g) as compared with acid treated bentonite (33mg/g).