The Principle of Polyacrylamide in Wastewater Treatment

Polyacrylamide molecules are commonly referred to as flocculants or coagulants. Their molecular structure contains positively charged groups (-CONH₂), enabling them to adsorb and bridge suspended particles in solutions, thereby exhibiting potent flocculation effects. Consequently, they find extensive applications. The working principle of polyacrylamide is detailed below: Adsorption bridging between polar groups and molecular chains The polar amide groups in polyacrylamide molecules readily adsorb onto sediment particle surfaces via hydrogen bonding interactions; Furthermore, its molecular chains can reach lengths of approximately 1000 while maintaining a width of only 1. This long-chain structure creates an enormous adsorption surface area in water, enabling the chains to “bridge” between particles. This promotes the aggregation of small particles into larger flocculent aggregates, thereby accelerating the sedimentation process. Electrostatic Matching Flocculation Mechanism in Wastewater In domestic sewage treatment and organic wastewater treatment applications, polyacrylamide exhibits cationic properties in both acidic and alkaline media. It can induce flocculation and sedimentation of negatively charged suspended particles in wastewater (whereas anionic polyacrylamide operates through the opposite mechanism). Optimization of Hydrolysis Reactions for Flocculation Effectiveness Polyacrylamide undergoes hydrolysis when exposed to alkaline substances such as NaOH, forming a copolymer composed of polyacrylamide and sodium polyacrylate—an anionic polymer flocculant. Partially hydrolyzed molecular chains extend from their original coiled state, significantly increasing surface area and enhancing bridging capacity. Consequently, their flocculation performance surpasses that of unhydrolyzed ionic products. However, when addressing adsorption and bridging interactions with ionic clay-type colloids, their flocculation efficacy may be marginally lower than other ionic products. Environmental Adaptability and Selection Recommendations As a highly reactive polymer compound, polyacrylamide exhibits flocculation properties that are relatively unaffected by fluctuations in water pH and salt content. For achieving effective flocculation and sedimentation in water treatment, anionic polyacrylamide is typically recommended. The main products of flocculant manufacturer Xinhuan Water Treatment are: White polyaluminium chloride (food grade), drinking grade polyaluminium chloride, industrial grade polyaluminium chloride, anionic polyacrylamide, cationic polyacrylamide, nonionic polyacrylamide, petroleum recycling polyacrylamide, oil recovery polyacrylamide, polyacrylamide, polymer flocculant polymer flocculation coagulant, polymeric ferrous sulphate, polymerized iron and aluminium chloride, and other water treatment chemicals. Welcome customers to write to us to negotiate business! Tel/WhatsApp：86 19139972558 Email：Sunny@xhwtm.com Contact:Sunny