Modified guar gum/SiO2: development and application of a novel hybrid nanocomposite as a flocculant for the treatment of wastewater

Abstract

Using the sol gel process, a novel hybrid nanocomposite (g-GG/SiO₂) has been developed in the authors' laboratory by grafting synthetic polyacrylamide chains on a guar gum backbone (g-GG) in the presence of microwave irradiation followed by in situ nanosilica incorporation on the surface of g-GG. Various characterization methods propose that g-GG promotes silica polymerization and probably acts as a template for nanoscale silica formation. Rheological characteristics indicate the gelling properties of the hybrid material. The application of the composite material in flocculation has been investigated on the laboratory scale as well as on the pilot scale. The flocculation kinetics and mechanism have been explained on the basis of pH of the suspension and flocculant dosage. Because of strong matrix–nanofiller interactions as well as enhanced molecular weight and hydrodynamic radius, the modified biopolymer-based nanocomposite provides excellent potential as a flocculant for the treatment of various synthetic and industrial effluents through a green disposal technique.