Cationic Polyacrylamide (CPAM) 9003-05-8

Cationic Polyacrylamide (CPAM) is a water-soluble synthetic polymer carrying a positive charge, produced by copolymerizing acrylamide with cationic monomers that introduce quaternary ammonium groups. It is the primary flocculant used for organic sludge dewatering and negatively charged colloidal systems in municipal and industrial wastewater treatment.

Cationic PAM is best suited for treating organic-rich, negatively charged suspensions such as municipal sewage sludge, food processing wastewater, and biological treatment effluent. Anionic PAM is better for mineral tailings and inorganic industrial wastewater. Nonionic PAM is used in acidic or high-ionic-strength conditions. The choice depends on the surface charge of the particles to be flocculated.

In sludge dewatering, CPAM is dosed into thickened sludge before mechanical dewatering equipment such as belt filter presses, centrifuges, or screw presses. The cationic polymer neutralizes the negative charge on organic particles and bridges them into large, strong flocs that release water readily. This produces higher cake solids content, reduces sludge volume, and lowers transportation and disposal costs.

Cationicity refers to the percentage of cationic monomer units in the polymer chain, typically ranging from 10% to 60%. Higher cationicity polymers have stronger charge neutralization capacity and are generally used for sludge with higher organic content or greater negative surface charge. Lower cationicity polymers provide better bridging performance. The optimal cationicity depends on the specific sludge characteristics and is best determined through jar testing.

CPAM powder should be stored in a cool, dry place away from moisture, heat, and direct sunlight. For solution preparation, the powder must be added slowly to agitated water — never the reverse. Typical working solution concentrations are 0.1-0.5%. Solutions should be prepared fresh as they degrade over time. Avoid high-shear pumps and mixing that can break polymer chains. Under proper dry storage conditions, shelf life is 24 months.