化学沉淀法对水中钼、钴金属污染物的应急处理技术研究

Emergency treatment technology of molybdenum and cobalt contamination with chemical precipitation in water

通过混凝试验,研究了化学沉淀法去除钼、钴金属污染物的可行性、最佳处理条件及最大应对能力。结果表明,采用三氯化铁作混凝剂,混凝前原水pH值调至7.0～7.6,可有效去除钼,其最佳pH值为7.0,且在钼标准限值10倍浓度条件下依然有良好的去除效果,但钼标准限值50,100倍浓度条件下,混凝沉淀后上清液钼浓度均无法达标;采用聚合氯化铝作混凝剂则无法有效去除钼。采用三氯化铁和聚合氯化铝作混凝剂,混凝前将水样pH值分别调至9.6～10.0和9.25～9.5,均可有效去除钴,其最佳pH值分别为9.75和9.5;在钴标准限值10,50和100倍高浓度条件下,聚合氯化铝作为混凝剂的去除效果明显优于三氯化铁,混凝沉淀后上清液钴浓度均能达标。

The feasibility, the optimal condition for treatment and the maximum removal efficiency of molybdenum and cobalt in water were investigated with a chemical precipitation method. The result showed that using ferric chloride as coagulant and adjusting pH of raw water to a range of 7.0 - 7.6 before coagulation, molybdenum could be removed effectively. The optimal pH was 7.0. It had good removal efficiency of molybdenum when the concentration was 10 times of the molybdenum water standard limit, but molybdenum in the supernatant after coagulation and sedimentation could not reach the standard limit when the water concentrations were 50 and 100 times. Using ferric chloride and PAC as coagulants, and adjusting pH to the range of 9.6 be removed effectively and the optimal adjusted efficiency of using PAC as coagulant was obviously 0 and 9.25 - 9.5 before coagulation, cobalt could were 9. 75 and 9. 5 respectively. The removal tter than ferric chloride, and cobalt concentrations in the supernatant after coagulation and sedimentation could reach the cobalt water standard limit when the cobalt concentrations in water were 10, 50 and 100 times of the standard limit.