分散聚合法制备耐盐型两性絮凝剂及絮凝性能

以丙烯酰胺(AM)为主体，同时引入正、负2种电荷基团单体，在盐水介质中采用分散聚合法，成功制备了耐盐型两性絮凝剂（P（AM/AA/DMBAC），简称AAB系列）。 系统地考察了分散介质、分散剂、单体浓度和链转移剂（次磷酸钠、甲酸钠）用量对两性絮凝剂AAB特性粘数和表观黏度的影响，确定了最佳反应条件为：n(AM)∶n(AA)∶n(DMBAC)=90∶5∶5，w（单体含量）=13%、w（PDAC）=6%(基于单体总质量)、w（硫酸铵）=25%(基于体系质量)、w（引发剂（VA-044））=0.2%(基于单体总质量)、ρ（次磷酸钠）=0.05 g/L、ρ（甲酸钠）=1.0 g/L，反应温度35 ℃，反应时间24 h，并通过絮凝试验评价了该两型絮凝剂的絮凝性能和耐盐性。 结果表明，在最佳反应条件下，两性絮凝剂具有较大的特性粘数（5.2 dL/g）和良好的稳定性；在高盐浓度的模拟污水中，两性絮凝剂具有使用剂量小（30×10-6），絮团沉降速率快（2.56 s-1）等优点，表现出优异的絮凝能力和良好的耐盐性。

Synthesis and Flocculation Performance of Salt Resistance Amphoteric Flocculants by Dispersion Polymerization

Series of amphoteric flocculants AAB with outstanding flocculation efficiency and salt tolerance were synthesized by dispersion polymerization using acrylamide(AM) as the main part and positive and negative charge groups as the monomers. The effects of the dispersion medium, stabilizer， monomer and chain transfer agent on the polymerization were investigated by determining the intrinsic viscosity of the copolymer and apparent viscosity. Meanwhile, the flocculation performance and salt resistance of the flocculants were evaluated by flocculation test. Then the optimum reaction conditions were determined as follows：n(AM)∶n(AA)∶n(DMBAC)=90∶5∶5, 13%(mass fraction) monomer, 0.2% VA-044 as initiator and 6% PDAC as stabilizer(based on the total monomer mass), 25% ammonium sulfate(based on the system), 500×10-6 sodium hypophosphite, 1000×10-6 sodium formate, polymerization temperature 35 ℃, polymerization time 24 h. Under the optimum reaction conditions, the amphoteric flocculants had the maximum intrinsic viscosity(for 5.2 dL/g) and better stability. All the results showed that the amphoteric flocculants exhibited excellent flocculation efficiency and salt tolerance due to the lower dosages(for 30×10-6) and the higher settlement rates(for 2.56 s-1) in simulated wastewater with high salt concentration.