As the green transformation of the papermaking industry enters a critical stage, the innovation of wastewater treatment technology has become the key to breaking through environmental protection bottlenecks. Recently, a hybrid flocculation system composed of polydiallyldimethylammonium chloride (PolyDADMAC) and polyacrylamide (PAM) has achieved a major application breakthrough in the field of pulp and paper mill wastewater treatment. Its synergistic effect enables efficient pollutant removal and water resource recycling, providing a new solution for water conservation and pollution reduction in the industry.
The papermaking industry is a major water consumer. In 2025, the water consumption of large-scale enterprises reached 1.62 billion cubic meters, and the wastewater treatment volume accounted for 5.6% of the total industrial wastewater in China. Traditional treatment processes face pain points such as incomplete pollutant removal, large sludge production, and low water resource recovery rate. However, the emergence of the PolyDADMAC-PAM hybrid flocculation system has effectively solved this problem through a synergistic mechanism of "charge neutralization + bridging flocculation". Studies have shown that as a cationic polymer, PolyDADMAC can quickly neutralize the negative charges of pollutants such as fibers and lignin in papermaking wastewater due to its high positive charge density, disrupting colloid stability and causing destabilization and aggregation. Polyacrylamide, on the other hand, forms a "bridging" effect through its ultra-long molecular chains, aggregating tiny flocs into dense large flocs and significantly improving the efficiency of sedimentation and separation.
In terms of core performance, this hybrid system has demonstrated excellent purification capabilities. The latest research in China Pulp & Paper shows that when nanocellulose-modified cationic polyacrylamide is compounded with PolyDADMAC and the dosage ratio is optimized, the chemical oxygen demand (CODCr) removal rate of papermaking wastewater can reach 92%-93%, and the suspended solids (SS) removal rate can reach 90%-91%. International studies further confirm that when PolyDADMAC with a molecular weight of 15.7×10⁴ g/mol is combined with PAM at a dosage of 6.0 mg/L, the removal effects of turbidity and total suspended solids (TSS) are optimal. Moreover, PolyDADMAC can regulate the ζ potential to approach zero, enhancing the destabilization effect, while the addition of PAM can significantly increase the volume of flocs and improve separation efficiency.
