Comparison of leaching characteristics of heavy metals in APC residue from an MSW incinerator using various extraction methods.
Comparison of leaching characteristics of heavy metals in APC residue from an MSW incinerator using various extraction methods.
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DOI：
10.1016/j.wasman.2008.04.006
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发表时间：
2009
期刊：
影响因子：
8.1
通讯作者：
K. Chiang;Chen-Chiu Tsai;Kuen‐Sheng Wang
中科院分区：
文献类型：
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作者：
K. Chiang;Chen-Chiu Tsai;Kuen‐Sheng Wang
研究了不同液固比(L/S)、不同pH控制和不同类型浸出剂的4种浸取方法(水浸提法、毒性特性浸出法、改良pH控制浸出法和序贯化学萃取法)对垃圾焚烧炉大气污染控制残渣中重金属浸出浓度的影响。结果表明，对于蒸馏水浸出，重金属浸出浓度(mg/L)随L/S比的增加而降低，而重金属释放量(重金属浸出量与被试样品重量之比(mg/kg))随L/S比的增大而增加，范围为2~100。结果还表明，在TCLP和改进的TCLP试验中，淋溶浓度和释放的金属量都强烈地依赖于pH。PH值低于6.5时，Cd、Pb2+、Cd、Cd、Cd当pH高于6.5时，铬和锌几乎不溶。同时，Cd和Cu也表现出类似的趋势，但在PHS分别为8.5和7.5。由于两性元素的性质，在pH值大于7时，铅的浸出浓度随pH的升高而增加。在改进的TCLP试验中，当pH值控制在与SCE试验相同的水平时，重金属形态接近SCE可提取的碳酸盐结合态。从SCE和改进的TCLP测试中浸出的目标金属量都远远高于常规TCLP和水提取测试的量。
This study investigates four extraction methods (water extraction, toxicity characteristics leaching procedure (TCLP), modified TCLP with pH control, and sequential chemical extraction (SCE)), each representing different liquid-to-solid (L/S) ratios, pH controls, and types of leachant, and their effects on the leaching concentration of heavy metals in municipal solid waste (MSW) incinerator air pollution control (APC) residue. The results indicated that for extraction with distilled water, the heavy metal leaching concentration (mg/l) decreased with L/S ratio, but the amount of heavy metal released (AHMR), defined as the leached amount of heavy metals to the weight of the tested sample (mg/kg), increased with an increase in L/S ratio, in the range of 2–100. The results also showed that both the leaching concentration and the amount of released metals were strongly pH-dependent in the TCLP and modified TCLP tests. In the case of pHs lower than 6.5, the leaching concentrations of Cd, Pb, Cu, Zn, and Cr decreased with an increase in pH. As pH increased higher than 6.5, Cr and Zn were almost insoluble. Meanwhile, Cd and Cu also showed a similar trend but at pHs of 8.5 and 7.5, respectively. Due to the nature of amphoteric elements, in the case of pHs higher than 7, the Pb leaching concentration increased with increasing pH. In modified TCLP tests with the pH value controlled at the same level as in the SCE test, the heavy metal speciation approached the extractable carbonate bound fraction by the SCE. Both amounts of targeted metals leached from the SCE and modified TCLP tests were much higher than those for the regular TCLP and water extraction tests.