聚合铁复合絮凝剂用于城镇纳污河河水化学强化处理的性能及机理研究

为提高城镇纳污河河水化学强化处理的效果,研制出一系列具有不同碱化度(B)、不同二甲基二烯丙基氯化铵聚合物(简称PDMDAAC)质量分数〔w(PDMDAAC),以下简写为w(P)〕、不同PDMDAAC黏度(η)的聚合铁复合絮凝剂PFC-PDMDAAC,对比了该絮凝剂与聚合氯化铁(PFC)或PDMDAAC以及二者先后投加时,对城镇纳污河河水的絮凝效果及絮凝机理,考察了B值、w(P)、η值对絮凝效果及机理的影响。实验结果表明,PFC-PDMDAAC具有最佳的絮凝效果,在投加量为3.0 mg.L-1时,其对COD和总磷的去除率均达到80%以上,与PFC、PDMDAAC、PFC+PDMDAAC、PDMDAAC+PFC相比,COD去除率分别提高12.4%、27.9%、5.6%和9.6%,总磷去除率分别提高7.8%、26.5%、20.2%和10.6%。对于PFC-PDMDAAC〔B=1.0、w(P)=7.0%、η=0.80 dL/g〕,适当降低B值(0.5)、提高w(P)(14.0%)或η值(1.21 dL.g-1)均可改善其絮凝性能,在投加量为3.0 mg.L-1时,COD去除率可分别提高1.0%、3.0%和2.4%,总磷去除率可分别提高0.4%、0.9%和2.3%。电中和作用是PFC-PDMDAAC的主要作用机理。

Study of Performance and Mechanism of Polyferric-organic Composite Flocculants in Chemically Enhanced Treatment of Wastewater Received by Urban Rivers

A series of flocculants polyferric-chloride(PFC)-polydimethyldiallyammonium chloride(PDMDAAC) with different basicity(B) of PFC,different weight percentage(w(P)) and intrinsic viscosity(η) of PDMDAAC were prepared.The coagulation efficiency and mechanism of the composite coagulant(PFC-PDMDAAC) were compared with those of PFC or PDMDAAC and successive addition of PFC and PDMDAAC in treating wastewater in urban river.The effect of B value,w(P) value and η value on coagulation efficiency and mechanism was also studied.The results showed that PFC-PDMDAAC was the most efficient coagulant in this study and achieved more than 80% removal for both COD and phosphorus.Compared with those of PFC,PDMDAAC,PFC+PDMDAAC and PDMDAAC+PFC,the COD removal rate of PFC-PDMDAAC increased by 12.4%,27.9%,5.6% and 9.6%,and the phosphorus removal rate increased by 7.8%,26.5%,20.2% and 10.6% respectively at the dosage of 3.0 mg·L-1.The performance of PFC-PDMDAAC(B=1.0,w(P)=7.0%,η=0.80 dL/g) was improved at a lower B value(0.5),larger w(P)(14.0%) and η value(1.21 dL/g),and the COD removal rate increased by 1.0%,3.0% and 2.4%,the phosphorus removal rate increased by 0.4%,0.9% and 2.3% respectively at the dosage of 3.0 mg·L-1.Charge neutralization is dominant mechanisms for PFC-PDMDAAC.