强化混凝沉淀去除水中三种二价重金属离子的试验研究

Experimental studies of removal of three divalent heavy metal ions with enhanced coagulation

本研究模拟水源水分别受到5倍超标的铅、镍、镉3种重金属的污染,考察了常规混凝工艺的去除效果,温度对于混凝-沉淀工艺去除3种重金属污染的效果影响,并本文重点研究了pH值对于去除3种重金属效果的影响。结果表明,常规混凝沉淀工艺无法将该污染水处理达标,混凝剂聚合氯化铝(PAC)投量为90mg.L-1时,可以取得相对较好的混凝效果;温度对混凝沉淀的影响不大;提高水源水的pH值可以显著的提高重金属的去除效果,分别将源水的初始pH值提高到8.1、9.9、10.2时,可以分别将5倍超标的铅、镍、镉污染水处理达标,实际应用中可以采用分阶段投碱的方法,始终保持受污染水的pH值分别为7.25、8.44、8.75,即可将受污染水处理达标。

The simulation of source water were exceeded by 5 times of lead,nickel,cadmium pollution of three heavy metals.The effects of removal of conventional coagulation process were investigated,and the effects of temperature for coagulation-precipitation process to remove three heavy metals were tested.In addition,this paper focused on the effect of pH for the removal of three heavy metals.The results show that conventional coagulation and sedimentation process can not treat the polluted water up to standard,PAC coagulant（PAC）dosage of 90mg·L-1 can have a relatively good coagulation effect.The temperature has little effect on the coagulation,but the coagulation result can be improved observably when the pH value is rising.When the pH value is rised to 8.1,9.9,10.2,the contaminated water can be treated up to standard.As for practical use,the alkali can be throwed in the contaminated water repeatedly,when the pH value is kept as 7.25,8.44,8.75 from beginning to end,the contaminated water can be treated up to standard.