【摘要】 采集某电镀厂污泥,以膨润土和改性膨润土为稳定剂,采用TCLP毒性浸出试验分析膨润土和改性膨润土对污泥中重金属Cr、Cd、Zn和Pb的稳定化效果。未加入稳定化剂前,电镀污泥中重金属Cr、Cd、Zn和Pb的浸出毒性分别为154 mg/L、13.5 mg/L、658 mg/L和76 mg/L。稳定化试验结果表明,在膨润土和改性膨润土的投加量与干污泥的质量比分别为1∶5和3∶10,振荡时间为12 h时,浸出液中重金属质量浓度最低,稳定化效果最好。形态分析结果表明,加入膨润土和改性膨润土稳定后重金属以有机结合态和残渣态为主,与未稳定前相比污泥中重金属不稳定态的含量变少。扫描电镜和红外分析结果表明,膨润土和改性膨润土可能通过吸附和离子交换来稳定污泥中的重金属。研究表明,改性膨润土对电镀污泥中高含量重金属的稳定化效果要优于未改性膨润土的稳定化效果。更多还原

【Abstract】 The paper is entitled to study the effects of the bentonite and its modified version on the stabilization of the heavy metal contents in the electroplating sludge by using the sludge samples we have collected from an electroplating factory with noticeable concentration rate of heavy metals in. For the study purpose,we have adopted a method known as the toxicity characteristics leaching procedure( TCLP) in hoping to stabilize the effects of the bentonite and its modified version on the heavy metal contents in the said sludge. The stabilization experiment results we have obtained prove that the leaching toxicity rates of the heavy metals Cr,Cd,Zn and Pb in the sludge account for 154 mg/L,13. 5mg/L,658 mg/L and 76 mg/L respectively,on the condition with no bentonite and modified bentonite added,thus,suggesting that the effects of the heavy metals in the leaching solution can be lowest if it is possible to satisfy the dosage range limit and the oscillation time. For example,on the condition that the oscillation time we have chosen is 12 h and the addition amounts of bentonite and modified bentonite are equal to 0. 2 g/g and 0. 3 g/g. Such stabilizing effects of the heavy metals in the sludge can be made optimistic when the heavy metal contents to be treated with bentonite and modified bentonite are mainly made of organic contents in the residual state. In such a situation,the content rate of the unstable state would be lower than that of the sludge without being treated by the bentonite. Moreover,the heavy metal contents in the sludge treated by the modified bentonite may tend to be less active than that in sludge treated by the unmodified one. However,the results of the infrared spectrum analysis demonstrate that the basic structure of the modified bentonite tends to remain unchanged. What is more,the electronic microscopy scanning also proves that the modified bentonite tends to assume more sheet and layered structures on the surface. At the same time,the adsorption power of the modified bentonite can slightly be made higher than that of the unmodified. Hence,it can be inferred that the stabilizing mechanism of heavy metals in the sludge by bentonite and modified bentonite can be mainly displayed through adsorption and ion exchange based on the above analysis,which suggests that the stabilization effect gained by with the modified bentonite turns to be better than that with the unmodified one.更多还原