不同钝化剂对城市地下固体废弃物重金属的钝化作用

采用实验室模拟,研究了6种重金属钝化剂(粉煤灰、脱硫石膏、磷矿粉、海泡石、膨润土、生物炭)以不同添加比例(0%、3%、7%、10%)对城市地下固体废弃物二乙基三胺五乙酸{HOOCCH_2NCH_2CH_2N(CH_2COOH)_2]~2,DTPA}可提取态重金属Cu、Zn、Pb、Cd含量的影响。结果表明,粉煤灰、脱硫石膏、磷矿粉、海泡石、膨润土、生物炭6种钝化剂均可以降低DTPA可提取态Cu、Zn、Pb、Cd的含量,表明这6种钝化剂对城市地下固体废物重金属Cu、Zn、Pb、Cd均具有钝化作用,且随添加比例的增高,钝化作用越明显,但钝化效果有所差异。膨润土的对Cu、Pb、Cd的钝化作用最明显,对Zn也有一定的钝化作用,因此,可优先选择膨润土作为城市地下固体废物重金属的钝化剂。

Passivation Effect of Stabilitying Materials on Heavy Metals in Municipal Solid Waste

The laboratory simulation test was conducted to study the passivation effect of six kinds of passivators (i.e. fly ash, gypsum, phosphate rock powder, sepiolite, bentonite and biological activated carbon) with different adding proportion (0, 3, 7%, 10%) for the heavy metals Cu, Zn, Pb, Cd in the urban underground solid wastes by the change of contents of DTPA extractable Cu, Zn, Pb, Cd. The results showed that the six kinds of passivators, i.e. fly ash, gypsum, phosphate rock powder, sepiolite, bentonite and biological activated carbon all can reduce the contents of DTPA extractable Cu, Zn, Pb, Cd, indicating that the 6 kinds of Passivators were of the passivation effect for the heavy metals of Cu, Zn, Pb and Cd in the urban underground solid wastes. Meanwhile, the passivation effect was more significant with the increasing adding proportion of passivators although the passivation effect were different for the six kinds of passivators. By comparing the passivation effect of the six passivators, the passivation effect of bentonite for Cu, Pb, Cd was most significant, and there was certain passivation effect for Zn, therefore, bentonite can be selected as a passivating agent for the heavy metals in urban underground solid waste.