Cationic Polyacrylamide (CPAM)

About This Product

Cationic polyacrylamide is a synthetic water-soluble polymer of very high molecular weight, typically several million daltons, carrying positively charged groups along the chain. It is supplied as a white granular powder, as an emulsion or as a solution, and is specified by molecular weight and charge density. It is important to distinguish flocculation from coagulation, because the two are sequential rather than alternative. A coagulant such as alum or PAC neutralises particle charge so fine particles can approach one another, producing small, fragile microflocs. A flocculant then binds those microflocs together: the polymer chain is long enough to adsorb onto two or more particles simultaneously, physically bridging them into large, dense, strong agglomerates that settle rapidly and dewater well. Charge density and molecular weight are chosen against the application, since high charge suits highly negative sludges while very high molecular weight gives the strongest bridging. Cationic grades suit organic sludges, which carry a strong negative charge. Dissolution matters: the powder must be wetted slowly into vigorously stirred water or it forms gel lumps that never dissolve. It is used in municipal and industrial sludge dewatering, wastewater clarification, paper retention and drainage, and in mining and mineral processing. Bio Green Chem supplies CPAM to specification on molecular weight, charge density, solids content, residual monomer and dissolution time.