具有氧化性能混凝剂的研发及对有机物的去除效果

Development of Oxidizing Coagulant and Its Organic Matter Removal Efficiency

通过将零价纳米铁(nZVI)与Al13进行复配,研发了兼具原位氧化功能的高电荷聚合态混凝剂nZVI@Al13,考察了nZVI、Al13不同配比和pH值等因素对有机物去除效果、分子质量分布及结构组成的影响。结果表明,混凝剂复配后,Al13中高聚合态铝含量增加,提高了混凝剂的混凝效率。中性条件下,腐殖酸(HA)去除率随A%投量的增加先增大后趋于平缓,Al13的最佳投量为0.03mmol/L,此时HA去除率约为70%;单独nZVI对HA的最大吸附去除率仅为10%;nZVI和Al13复配后对HA的去除效果好于单独两种方式的加和,nZVI对A%的强化混凝起到协同作用。当pH值>7.0时,过多的OH-使得Al13解聚,影响混凝效果,nZVI和Al13对HA的去除效果均有所下降。当pH值<7.0时,复配混凝剂对HA的去除率均优于单独Al13最大去除率达到84%。复配混凝剂对分子质量<2000u的有机物的去除效果较单独Al13提高了约8%。

A novel coagulant ( nZVI@ Al13 ) with oxidizing ability was prepared by combining nZVI and Al]3. The effects of dosage and pH on the organic matter ( OM) removal, the molecular weight distribution and the structure composition of OM were analyzed. The results showed that the concentration of high-polymeric aluminum in Al13 increased after the coagulant was reconstituted, which further increased the coagulation treatment efficiency. Under neutral conditions, with the increase of Al13 dosage, the HA removal efficiency was firstly increased and then stabilized. The optimal Al13 dosage was 0.03 mmol/L, and the HA removal rate was approximately 70%. The adsorption removal rate on HA using nZVI alone was 10%. The removal efficiency of HA by nZVI@Al13 was better than the total efficiency of nZVI and Al13 when used separately. The nZVI showed a synergistic effect on Al13 enhaneed coagulation. At pH >7.0, excessive OH^- depolymerized Al13 and decreased the coagulation effect of the coagulant, therefore the removal efficiency of HA was reduced. At pH <7.0, the removal efficiency of HA by nZVI@ Al13 was higher than using Al13 separately, and the maximum removal rate reached 84%. The removal efficiency of compounded coagulants on organic matter with a molecular weight less than 2000u was about 8% higher than that of using Al13 separately.