Polyacrylamide (PAM) is a linear polymer compound synthesized by homopolymerization of acrylamide monomers or copolymerization with other monomers. It is an important water-soluble polymer with unique physicochemical properties. It is easily modified into various branched or network structures through grafting or crosslinking, and is widely used in various sectors of the national economy, earning it the title of "auxiliary agent for all industries." Compared with inorganic polymeric flocculants, PAM has advantages such as low dosage, strong flocculation ability, low pH sensitivity, rapid sedimentation, and low sludge production. During use, PAM is readily soluble in water and exhibits good thermal stability.

Cationic PAM typically flocculates colloidal particles in wastewater or sludge through adsorption bridging and charge neutralization, forming larger flocs. Currently, PAM is widely used in oily wastewater, dyeing and printing wastewater, papermaking wastewater, and residual sludge after biochemical treatment, and it also has excellent decolorization capabilities.

Different polymers can be obtained depending on the cationic monomers involved in the polymerization reaction. The main cationic monomers include: methacryloyloxyethyltrimethylammonium chloride (DMC), acryloyloxyethyltrimethylammonium chloride (DAC), and dimethyl diallyl ammonium chloride (DMDAAC).

The preparation of CPAM flocculants typically involves: 1. cationic modification of nonionic PAM; 2. copolymerization of acrylamide with cationic monomers; 3. grafting CPAM flocculants with natural polymers. Copolymerized products are particularly noteworthy due to their controllable charge, uniform charge distribution, and simple preparation process.