高锰酸盐复合剂强化混凝对水中天然有机物的去除机制研究

利用流动电流、絮凝脉动颗粒检测技术、分子量分布及XAD树脂分类技术对高锰酸盐复合剂强化混凝去除水中天然有机物的机制进行了研究.结果表明，高锰酸盐复合剂提高了硫酸铝的混凝效果，投加0.75 mg/L高锰酸盐复合剂后，较单独投加硫酸铝对天然有机物的去除率可提高13个百分点.流动电流(SC)检测结果表明，高锰酸盐复合剂使有机物表面所带的负电性减弱，稳定性降低.如单独投加60 mg/L硫酸铝时SC值为55.2，而投加0.50、 0.75和1.0 mg/L的高锰酸盐复合剂预氧化处理后，SC值分别升高至61.4、 69.6和87.0.投加高锰酸盐复合剂后，絮凝指数增加，表明高锰酸盐复合剂及反应过程中生成的新生态水合二氧化锰对混凝起到了强化作用.分子质量分布及XAD树脂分类结果表明，高锰酸盐复合剂提高了混凝过程对小分子质量和亲水性有机物的去除能力，如硫酸铝混凝后亲水性有机物的含量为1.90 mg/L，而投加高锰酸盐复合剂后，可使其含量降至1.32 mg/L.

Mechanism of Natural Organic Matter Removal by Potassium Permanganate Composite Enhanced Coagulation

Streaming current technique, fluctuation of transmitted light technique, molecular weight distribution and XAD resin adsorption technique were used to study the mechanism of natural organic matter removal by potassium permanganate composite(PPC) enhanced coagulation. Results showed that natural organic matter removal efficiency increased 13% by 0.75 mg/L potassium permanganate composite enhanced coagulation compared with that of alum coagulation alone. Streaming current indicated that potassium permanganate composite decreased the organic matter stability by reducing the surface negative charge, and the SC value increased from 55.2 to 61.4, 69.6 and 87.0 by addition of 0.50, 0.75 and 1.0 mg/L PPC. Coagulation index R indicated both nascent manganese dioxide and subsidiaries played an important role in potassium permanganate composite enhanced coagulation process. Potassium permanganate composite enhanced coagulation increased the removal efficiency of lower molecular weight and hydrophilic organic matter compared with alum coagulation, and hydrophilic organic matter can be reduced from 1.9 mg/L to 1.32 mg/L by the addition of 0.75 mg/L potassium permanganate composite.