Adsorption of m(II) (M = Mn, Cu, Zn) in various ph and contact time using chitosan-silica prepared by sol-gel method

Abstract

Chitosan–silica prepared by sol-gel method was used for adsorption of M(II) (M = Mn2+, Cu2+, Zn2+) in solution at room temperature. The prepared chitosan–silica was characterized by Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy (SEM). Effect of pH of the metal solution and adsorption contact time toward the adsorption capacity were investigated. The correlation between M(II) concentrations and the adsorption capacity, which was determined at optimum pH and optimum adsorption contact time, is also discussed. FTIR and SEM results are identical to that of chitosan–silica reported previously. Chitosan-silica performs the highest adsorption capacity for Cu2+, Mn2+, and Zn2+, successively. The optimum pH for Mn2+, Cu2+ and Zn2+ adsorptions were obtained at pH 5. It is suggested that due to the combination of ionic size and HSAB concept, Cu2+ gives the highest adsorption capacity than that of Mn2+ and Zn2+. The optimum contact time for Mn2+ and Cu2+ adsorption was obtained at 75 minutes with adsorption capacities of 6.56 ± 0.04 mg/g and 15.46 ± 0.02 mg/g, respectively, whereas Zn2+ adsorption was obtained at 60 minutes with an adsorption capacity of 5.01 ± 0.12 mg/g.