Mercapto functionalized silica entrapped polyacrylamide hydrogel: Arsenic adsorption behaviour from aqueous solution.

In this article, 3-mercaptopropyl functionalized silica entrapped polyacrylamide hydrogel (MPFS-PAA) was prepared and characterized by FT-IR, scanning electron microscopy (SEM) and energy dispersion X-ray spectroscopy (EDS). Synthesized hydrogel was evaluated for removal of arsenic(III) from aqueous solution. Adsorption studies were carried out by batch method as function of contact time, initial concentration of arsenic and pH. As(III) adsorption data fitted well with Langmuir and Freundlich isotherm models. Adsorption capacity of arsenic 92.5 μg/g was obtained at initial concentration of 100 μg/L by Langmuir isotherm. Adsorption kinetics was tested for pseudo-second order reaction at different contact time. The rate constants of pseudo second order reaction were calculated and good correlation coefficient R(2) 99.67 obtained. The results indicates that MPFS-PAA is an effective adsorbent for removal of As(III) from aqueous solution.