Facile Fabrication of Poly(vinyl alcohol)/Silica Composites for Removal of Hg(II) from Water

A low-cost and environment friendly route towards the synthesis of poly(vinyl alcohol)/silica composites is presented. The silica-based composites were synthesized by hydrolytic and dehydroxylation polymerization of a silica precursor, tetrakis(2-hydroxyethyl) orthosilicate by sol-gel method within a poly(vinyl alcohol) matrix. Calcination of the composites at 300 degrees C resulted in mesoporous silica that exhibited excellent Hg(II) adsorption at pH 6.5, and the materials were characterized using FTIR, XRD, TGA-DTA, and SEM analyses. The adsorption data best fitted the Langmuir isotherm; Q(max) for the adsorbent was 113.63 mg.g(-1). The adsorption followed pseudo-second-order kinetics with a rate constant of 6.16x10-4 g.mg(-1).min(-1). The biocompatibility feature of the synthesized adsorbent materials makes it a potential candidate for biological applications such as enzyme immobilization, opto-electronics, and sensors.