采用电动修复增强技术去除电镀污泥中重金属

Removal of heavy metals from electroplating sludge by electrokinetic enhancement technology

为提高电动修复技术去除电镀污泥中的重金属(Cu,Pb,Zn,Cr,Ni)的效率,采用污泥预酸化处理及阴极pH值控制处理2种途径进行强化,反应过程中电压为32V,处理时间为7d,结果表明,电镀污泥酸化pH值至4.5时,污泥中重金属的可移动性明显提高了,依次为Cr>Ni>Zn>Cu>Pb;污泥预酸化加阴极pH值控制处理能使电镀污泥中Zn、Ni、Cu和Pb交换态、碳酸盐结合态和有机硫化物态转化为可溶离子态,转化量大小依次为Ni>Zn>Cu>Pb,且该处理Zn、Ni、Cu和Pb的去除率分别达到74.02%、68.38%、39.22%、21.37%;但污泥预酸化及阴极pH值控制处理都不利于Cr的去除,对照处理Cr去除率为77.83%,污泥预酸化处理去除率降为40.65%,污泥预酸化加阴极pH值控制处理降至12.80%.

To enhance the heavy metals（Cu, Pb, Zn, Cr and Ni） removal from electroplating sludge by electrokinetic（EK） enhancement technology, the EK experiments were carried out with and without pH adjustment in cathode chamber of acidified electroplating sludge.The electrokinetic experiments were conducted under a constant potential（32V） during seven days of EK process.The selective sequential extraction（SSE） was used to determine the fractionation of heavy metals in the electroplating sludge.The mobility of heavy metals in electroplating sludge significantly increased after its acidification at the pH of 4.5 and followed the order：CrNiZnCuPb.After the experiment with acidified electroplating sludge and pH adjustment at cathode chamber, the removal efficiencies of heavy metals were：74.02% for Zn, 68.38% for Ni, 39.22% for Cu, 21.37% for Pb, and the exchangeable, carbonate and sulfate fractionations of heavy metals in initial electroplating sludge were converted to soluble fractionation.However, electroplating sludge acidified treatment and pH adjusted in cathode chamber of acidified electroplating sludge treatment were not beneficial to improve the removal efficiency of Cr, the removal efficiency of Cr decreased from 77.83% of control treatment to 40.65% of electroplating sludge acidified treatment, and furthermore, decreased to 12.80% of pH adjusted in cathode chamber of acidified electroplating sludge treatment.