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℃ 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 6.16×10^-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.[Figure not available: see fulltext.]