Sol–gel polycondensation of tetraethoxysilane in ethanol in presence of vinyl modified guar gum: synthesis of novel nanocompositional adsorbent materials

Novel nanocomposite adsorbent materials were synthesized by condensation polymerization of TEOS in the presence of saponified guar-graft-poly(acrylonitrile) (SG) as template. The effect of changing the molecular size of SG on the final properties of the composite materials was investigated in this paper. The composites were thermally treated at temperatures ranging from 80 to 1100 °C, to obtain materials of different performance. The chemical, structural and textural characteristics of the composites were determined by FTIR, XRD, TGA-DSC and SEM studies. Their adsorption properties were monitored in terms of Zn (II) binding capacity which could be tailored by changing the template size and sintering temperature. The adsorption capacity of the composite at room temperature was enhanced five times when thermally treated at 900 °C with a maximum adsorption of 3.58 meq/g of the zinc (II). The adsorption could be further optimized to higher values and the materials could be successfully recycled for three consecutive cycles without any significant loss in the adsorption capacity.