Facile Fabrication of Poly(vinyl alcohol)/Silica Composites for Removal of
Hg(II) from Water
Abstract: 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 C resulted in mesoporoussilica that exhibited excellent Hg(II) adsorptionat pH 6.5, and the materials were characterized using FTIR, XRD, TGA-DTA, and SEM analyses. 
The adsorption data best fitted the Langmuir isotherm; Qmaxfor 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.