电石渣脱硫废水中超标重金属的去除

HEAVY METALS REMOVAL FROM THE CARBIDE SLAG DESULFURIZATION WASTEWATER

针对电石渣脱硫废水存在重金属超标问题,采用化学沉淀法去除废水中Cd^2＋和Hg^2＋。以二硫代氨基甲酸盐（DTCR）为螯合剂,分别处理模拟含Cd^2＋或Hg^2＋废水、同时含Cd^2＋和Hg^2＋废水,以及实际电石渣脱硫废水。结果表明,投加量150 mg/L的DTCR能使模拟废水中的Cd^2＋和Hg^2＋从质量浓度10 mg/L分别降低到41μg/L和34μg/L;190 mg/L的DTCR能使实际电石渣脱硫废水Cd^2＋和Hg^2＋的质量浓度分别降低到42μg/L和2.0μg/L。DTCR去除电石渣脱硫废水中Cd^2＋和Hg^2＋的效率很高,pH升高略有利于提高Cd^2＋和Hg^2＋的去除效果,但在4～10内均能达到DL/T 997-2006排放要求。

High concentration of cadmium and mercury heavy metals in carbide slag desulfurization wastewater was removed via chemical precipitation.Dithiocarbamate（DTCR） was adopted to chelate Cd^2＋and Hg^2＋and separated them from the simulated wastewater and industrial wastewater. The results show, while both Cd^2＋and Hg^2＋were simultaneously removed from 10 mg/L to 41 μg/L and 34 μg/L, respectively, when 150 mg/L DTCR added into the simulated wastewater. When the industrial water was treated, mass concentration of Cd^2＋and Hg^2＋were reduced to 42 μg/L and 2.0 μg/L respectively by190 mg/L DTCR. Thus, Cd^2＋and Hg^2＋could be removed effectively from the carbide slag desulfurization wastewater by DTCR in the pH range of 4～10to meet the national discharge standard of DL/T 997-2006.