酸根离子对铝板电絮凝处理含镍废水的影响

电絮凝是去除废水中重金属离子的有效技术。本研究考察了常见酸根离子SO42-、Cl-、NO3-和H2PO2-对铝板电絮凝除Ni2+的影响。结果表明，SO42-、Cl-、NO3-均有利于Ni2+的去除，其中由于NO3-的还原可提高铝阳极溶解效率，因此，当其浓度从0.0186增至0.186 mol/L时，反应30 min后Ni2+去除率从77.9%升至99.8%。H2PO2-会降低絮体絮凝活性并钝化电极，从而显著降低Ni2+去除率，其浓度从0.0186 mol/L增至0.372 mol/L，反应60 min后Ni2+去除率从91.7%降至30.5%。另外，对各阴离子存在下溶解态铝絮体聚合度以及电解过程pH的检测，进一步揭示这4种离子对电絮凝影响机制。

Effect of acid radical ions on removal of Ni2+ by electrocoagulation using aluminum electrodes

Electrocoagulation (EC) is an effective technique to remove aqueous heavy metal ions.In this study,the effects of SO42-,Cl-,NO3- and H2PO2- on the removal efficiency of Ni2+ using EC were systematically investigated with aluminum electrodes.The results indicated that the addition of SO42-,Cl- or NO3- was beneficial to improving EC efficiency.Ni2+ removal rate was enhanced from 77.9% to 99.8% within 30-min electrolysis while NO3- concentration increasing from 0.0186 to 0.186 mol/L,which was attributed to the promotion effect of NO3- reduction on the dissolution of aluminum anode.However,H2PO2- would restrict the flocculation activity of aluminum floc and passivate electrodes,which obviously resulted in the decrease of Ni2+ removal rate.When H2PO2- concentration increased from 0.0186 to 0.372 mol/L,the removal rate of Ni2+ decreased from 91.7% to 30.5% during 60-min reaction.In addition,the effects of these acid radical ions on EC reaction mechanism were further revealed by investigating the polymerization degree of dissolved aluminum floc and the variation of pH during the whole electrolysis process.