Ecology, Environment and Conservation Paper

ADSORPTION OF ARSENIC ONTO ACTIVATED CARBON OF CLERODENDRUM INERME

G. Alagumuthu and T. Sumathi

Abstract

The objective of this study is to assess the removal of As(III) from aqueous solution onto Clerodendrum inerme. The effect of various parameters has been investigated by batch adsorption techniques. The various variables studied include contact time, adsorbent dose, temperature and pH. The equilibrium data was analyzed using Langmuir, Freundlich, Temkin, Flory-Huggins (F-H) and Dubinin-Radushkevich (D-R) isotherm models. Analysis of the data shows that Langmuir described the data more appropriately than the Freundlich, F-H and D-R isotherms. Adsorption kinetics data was tested using Pseudo-first-order, pseudo-second-order, Elovich equation and intra-particle diffusion models. Kinetic studies showed that the adsorption followed a pseudo-second-order model. The intra particle diffusion model described that the intra particle diffusion was not the only rate-limiting step. Thermodynamic parameters (i.e., change in the free energy (ΔGo), the enthalpy (ΔHo), and the entropy (ΔSo)) were also evaluated. The overall adsorption process was endothermic and spontaneous in nature. EDX analysis indicated the presence of Arsenic on the C. inerme. These results suggest that Clerodendrum inerme could be employed as an efficient adsorbent for the removal of As(III) from aqueous solution.