Adsorption of Cadmium onto modified bentonites from aqueous solutions

The exchange of clay ions using salts of bis-imidazolium (MBM) could submit clayorganophilic materials which permit an effective conservation of cadmium in aqueoussolution.Imidazolium salts have already been used successfully for this purpose. Due this hydrophobicity, organo clays will be expected to behave as effective sorbent for organic pollutants, more particularly those having low solubility. For this purpose, the present study treats with bentonite modification MBM–Bt using para, meta and ortho bis-imidazolium salts and tries to retain harmful very toxic inorganic metal. The experiments on cadmium with different bentonites show increase of the maximum uptake capacities (q_m) from 3.65, 4.48, and 7.12 mg.g^-1 for o-MBM–Bt, m-MBM–Bt, p- MBM–Bt respectively. To provide the best description of cadmium adsorption behaviour we use different type of adsorption isotherms and kinetic models. According to the results obtained Langmuir model and the pseudo-second order are the most appropriate. The findings reported in this study aid in facilitating the extraction of cadmium resources from aqueous using modified bentonites.