Adsorption of Mn2+ and Zn2+ in Aqueous Solution by Using Aluminum Pillared Clay from Boboyo (Far North Cameroon)

Abstract

The use of clay materials in the treatment of filthy water and industrial waste is a promising way for the restoration of the environment. Following this view, clay materials of Boboyo (from Far North Region of Cameroon), specially made up of smectite, have been pillared with polyoxycations of aluminum. Next, some trials of adsorption of metallic ions Mn2+ and Zn2+ from aqueous solution mixture were carried out by varying the contact time, t, the pH, the initial concentration of heavy metals, Co and the temperature, T, °C. The kinetics of the reactions indicate  that the adsorption of Mn2+ and Zn2+ ions was very fast and attained equilibrium in 10 minutes. The adsorption capacity, Qe, of the modified clay increases with increasing pH up to pH = 6, and reduces when the pH becomes basic. This phenomenon also increases with the increase in the initial concentration of the metallic ions. It was observed that, temperature has a less influence on the retention capacity. The nature of the retention phenomenon of both heavy metal ions is exothermic and physical. The adsorption isotherms are comparable with the Langmuir and Freundlich models. The adsorbed quantities from the monolayer coverage deduced from Langmuir’s model are 24.4 mg/g and 24.6 mg/g for Mn2+ and Zn2+ ions respectively.