Synthesis, characterization of graft copolymers and their application in treatment of refinery wastewater

Abstract

This article presents the synthesis, characterisation, and application of graft copolymers for coagulation-flocculation for cleaning refinery wastewater. The grafted copolymer is prepared using potassium persulfate as an initiator under a nitrogen atmosphere, and polysaccharides (Starch, amylose, and guar gum) as backbone polymers and acrylamide as the monomer. The synthesised grafted copolymer is characterised using standard techniques, and the molecular weight is estimated using the Mark-Houwink equation. The coagulation-flocculation experiments were conducted using alum as a coagulant and the synthesised graft copolymers as flocculants. The efficiency of turbidity removal was evaluated by adjusting the pH during synthesis and measuring the supernatant turbidity values. Results showed that the grafted copolymer St-g-PAM-II exhibited turbidity removal efficiency of 92.19% at pH 10. These findings demonstrate the potential of the grafted copolymer as an effective flocculant in refinery wastewater treatment. The synthesis process and characterisation techniques provided valuable insights into the structural and morphological properties of the graft copolymers. The estimated molecular weights provided approximate values for their molecular size. Present study highlighted the importance of pH adjustment and the role of graft copolymers in turbidity removal. This research contributes to developing sustainable and efficient wastewater treatment methods with potential applications in the petroleum industry. © Indian Academy of Sciences 2025.