可变电荷土壤介入应急混凝处置镉污染的可行性研究

Study on the feasibility of enhanced coagulation with variable charge soil on emergency treatment of the Cd polluted raw water

以南方可变电荷土壤作为突发高浓度镉污染水体应急混凝处置的强化混凝药剂,考察了可变电荷土壤介入应急处置对混凝效果的影响。并模拟构建了镉污染应急处置产生沉积物,通过静态释放实验方式,开展了可变电荷土壤介入应急混凝处置对含镉沉积物中Cd释放的影响的研究。结果表明混凝时,在偏碱性条件下,投加可变电荷土壤有利于提高镉的去除率,可以将水体镉浓度由1.892 mg·L-1降到30μg·L-1。在静态释放实验中,不同的溶解氧条件下镉释放量存在差异,但可变电荷土壤介入应急混凝处置都不同程度地促进了沉积物中Cd的释放。在镉污染水体的应急处置中投加可变电荷土壤来强化混凝可以有效降低水体的残余镉浓度,但可变电荷土壤的介入使得沉积物组分发生了变化,使得混合沉积物在应急处置后具有二次污染的风险。

Utilizing the variable charge soil in southern China to enhance the coagulation process of high- concentration cadmium polluted water, the effect of variable charge soil applied to emergency water treatment for cadmium pollution was investigated. In addition, the sediments formed in the emergency treatment process were simulated, and the effect of variable charge soil on the cadmium release in the sediment was studied by the static release experiment. The results indicated that variable charge soil could improve the cadmium removal rate dur- ing coagulation in alkaline conditions and could reduce the Cd concentration from 1. 892 mg · L-1 to 30 μg · L-1. The static release experiment showed that the Cd release concentrations in different concentrations of dis- solved oxygen showed a significant difference. In addition, the variable charge soil used in the emergency treat- ment process stimulated the cadmium release from the sediment. In short, the addition of variable charge soil to enhance coagulation could effectively reduce the residual cadmium concentration. However, the addition of varia- ble charge soil changed the component of the sediment. In addition, the sediment mixed with variable charge soil posed the risk of secondary pollution.