The Study of Acrylamide/(N-Hydroxyethyl)acrylamide Copolymer as a Flocculant for Kaolin Suspensions

Acrylamide-based non-ionic polymers have gained significant attention for wastewater treatment due to their high flocculation efficiency. However, optimizing the polymer dosage and knowing the role of hydrogen bonding in flocculation remain challenging. In this study, acrylamide/(N-hydroxyethyl)acrylamide (AM/HEA) copolymers at different molar ratios were synthesized via solution polymerization. The polymers were characterized using FTIR, 1 H NMR, DSC, and TGA. The kaolin suspension was employed to evaluate the flocculation performance of copolymers by the jar test method. The AM/HEA copolymers showed superior flocculation efficiency, achieving 98% turbidity removal at an optimal polymer flocculant dose of 0.2 mg/L, with a stirring speed of 400 rpm and a stirring time of 180 s. Zeta potential and TEM imaging results showed that flocculation primarily occurred through polymer adsorption on the kaolin surface, with its coiled conformation may enhance particle bridging. These results emphasize the critical role of polymer molecular structure in optimizing flocculation performance and suggest AM/HEA copolymers as efficient flocculants for water treatment exercises.