Synthesis and performance of acrylamide-dimethylaminoethylacrylate methyl chloride quaternary salt copolymer as flocculant

PMSE 47

Ramesh Subramanian, rsubramanian@laurentian.ca, School of Engineering, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON P3E 2C6, Canada, Peter Reed, preed@nalco.com, Water and Core Technologies, Nalco Company, 1601 West Diehl Road, Naperville, IL 60563, and Shiping Zhu, zhuship@mcmaster.ca, Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4L7, Canada.
Flocculants play a crucial role in wastewater treatment, sludge dewatering, papermaking and mineral processing industries. Current commercial synthetic flocculants are mainly acrylamide/cationic (meth)acrylate copolymers manufactured via free radical polymerization mechanism or by post-reaction modification of polyacrylamide to give linear random cationic flocculants with relatively high molecular weight. (~ 1,000,000 g/mol). This is because it is extremely difficult to synthesize high-molecular-weight charged polymers such as polyquats, polyimines, and polyamines due to strong repulsion between the monomer units. In this study, graft and random microgel copolymers of N,N-dimethylaminoethylacrylate methyl chloride quaternary salt (DMAEA.MCQ) and acrylamide (AM) containing various amounts of the quaternary salt were synthesized in dilute solution via a free radical mechanism using gamma radiation. The flocculation performance of the synthesized copolymers was evaluated by turbidity tests on a model dilute titanium dioxide colloid suspension and compared with commercial random copolymers of DMAEA.MCQ and AM.