Adsorption of Zn(II) ions from aqueous environment by surface modified Strychnos potatorum seeds, a low cost adsorbent

Abstract

The surface modified Strychnos potatorum seeds (SMSP), an agricultural waste has been developed into an effective adsorbent for the removal of Zn(II) ions from aqueous environment. The Freundlich model provided a better fi t with the experimental data than the Langmuir model as revealed by a high coefficient of determination values and low error values. The kinetics data fi tted well into the pseudo-second order model with the coefficient of determination values greater than 0.99. The influence of particle diffusion and fi lm diffusion in the adsorption process was tested by fi tting the experimental data with intraparticle diffusion, Boyd kinetic and Shrinking core models. Desorption experiments were conducted to explore the feasibility of regenerating the spent adsorbent and the adsorbed Zn(II) ions from spent SMSP was desorbed using 0.3 M HCl with the effi ciency of 93.58%. The results of the present study indicates that the SMSP can be successfully employed for the removal of Zn(II) ions from aqueous environment.