摘要:
选择较理想的电压降,在不同络合剂条件下对污泥中主要重金属的动电去除效果进行研究。结果表明在1.0V·cm-1电压降条件下,污泥中铬的去除效果以柠檬酸处理最好,其去除率高达67.52%,分别比ED-TA、乳酸处理的高6.31%和6.79%,而这3种络合剂对污泥中铅和镉的去除效果差异不大,去除率分别在60%和80%左右。在1.0V·cm-1电压降、柠檬酸条件下,污泥中铬、铅和镉的去除率均随时间延长而逐渐增加,处理时间144h,污泥中铬、铅和镉的去除率均达总去除率的98%以上。经动电技术处理后污泥中铬、铅和镉总量分别为599.84mg·kg-1、128.88mg·kg-1和3.38mg·kg-1,均低于国家污泥农用的重金属控制标准。
关键词:
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污泥 /
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动电技术 /
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络合剂 /
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重金属 /
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去除效果
Abstract:
Effects of electro-kinetics at the optimal voltage drop on the elimination of major heavy metals in urban sludge were studied with various chelating agents.The results showed that the elimination of Cr in sludge was the greatest using citrate among all treatments under 1.0 V·cm-1 voltage drop.A 67.52% elimination rate was obtained,which was 6.31% and 6.79% higher than those using EDTA and lactate,respectively.The rates of Pb and Cd elimination using citrate,EDTA,and lactate under 1.0 V·cm-1 voltage drop were similar,ranging from 60% to 80%.The Cr,Pb,and Cr eliminations using citrate under 1.0 V·cm-1 voltage drop increased with treatment time.The elimination rates for Cr,Pb,and Cr in sludge after 144 h of treatment were more than 98%.The contents of Cr,Pb,and Cd in the resultant treated sludge were 599.84 mg·kg-1,128.88 mg·kg-1 and 3.38 mg·kg-1,respectively.They were all below the national standards for heavy metals in sludge for agricultural applications.
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