酸浸粉煤灰制备复合混凝剂及其处理生活污水的效果研究

研究了以粉煤灰和H_２ＳＯ₄为原料，常温常压下搅拌反应制备复合混凝剂的方法，考查了酸种类、酸浓度、酸灰比、搅拌时间等因素对Fe^３＋、Al^３＋溶出效果和生活污水混凝效果的影响.结果表明，酸灰比5 mL/g、浓度2 mol/Ｌ的H_２ＳＯ₄溶液与粉煤灰搅拌4 h并静置30 min后制得的混凝剂，其中Fe^３＋的浓度为0 .010 8 mol/Ｌ，溶出率为11 .4%；Al^３＋的浓度为0 .035 4 mol/Ｌ，溶出率为4 .3%；对生活污水的COD去除率70 .4%，SS去除率91 .9%，与市售聚合混凝剂效果相当，是一种有开发利用价值的水处理剂.

Preparation of a Composite Coagulant from Fly Ash and Its Application in Domestic Wastewater Treatment

Fly ash was investigated as a raw material for the preparation of a composite coagulant with sulfuric acid. Types of acid solution, H2SO4 concentration, ratio of H2SO4 to fly ash and stirring time were respectively examined as factors that influence the efficiency of converting the iron and aluminum components into a composite coagulant and coagulation performance on domestic wastewater. The coagulant was attained at the condition of H2SO4-fly ash ratio of 5mL/g, H2SO4 of 2mol/L, stirring time of 4h and stabling time of 30min, and contained Fe3+ of 0.0108mol/L with conversion efficiency of 11.4% and Al3+ of 0.0354mol/L with conversion efficiency of 4.3%. Removal efficiencies of COD and SS by this type of coagulant reached 70.4% and 91.9% respectively when treating domestic wastewater. This study provides a promising means to utilize fly ash for coagulation, which possibly makes wastewater treatment more economical and more sustainable.