Microwave based synthesis of polymethyl methacrylate grafted sodium alginate: its application as flocculant

► Polymethyl methacrylate grafted sodium alginate was synthesized by microwave assisted method. ► Higher the percentage grafting of the graft co polymer, higher is its intrinsic viscosity. ► The graft copolymer proved superior flocculant than sodium alginate in coal fine suspension. ► The optimized flocculant dosage as found in coal fine suspension was 0.375 ppm.