Youcai Zhao, Stucki S, Ludwig Ch, Wochele J
The State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
Waste Manag. 2004;24(6):581-7. doi: 10.1016/j.wasman.2004.01.004.
In this work, the impact of moisture on the volatility of heavy metals present in municipal solid wastes (MSW) in a laboratory scale simulated incinerator was studied, using synthetic waste consisting of 5.4 g of wood powder, 2.6 g lava, 1.9 polythene, 0.19 g polyvinyl chloride, and a given quantity of water and heavy metals represented by lead, zinc and copper in forms of metallic, chlorides and oxides. It is found that the presence of high moisture in MSW will greatly reduce the volatilization of heavy metals in MSW in the incineration process. The volatilization behavior of chlorides, oxides and the metallic species with respect to the effect of moistures is quite different. For copper, the presence of moisture in MSW depresses the volatilization of oxides, and increases that of chloride and the metallic species, while in contrast, the volatilization of both lead and zinc is always depressed by the presence of moisture in MSW, regardless of the chemical forms used. The chemical mechanisms, which govern the volatilization behaviors of different chemical forms in the incineration process, are proposed. Hydrolysis, dewatering of hydrolyzed species, sublimation, chemical transformation of less volatiles to more volatiles or reverse, may participate in and affect the volatilization of heavy metals in MSW.
在这项工作中，在实验室规模的模拟焚烧炉中研究了水分对城市固体废物（MSW）中重金属挥发性的影响，使用了由5.4克木粉、2.6克熔岩、1.9克聚乙烯、0.19克聚氯乙烯以及一定量的水和以金属、氯化物和氧化物形式存在的铅、锌和铜代表的重金属组成的合成废物。研究发现，城市固体废物中高水分的存在将大大降低焚烧过程中城市固体废物中重金属的挥发。氯化物、氧化物和金属物种关于水分影响的挥发行为有很大不同。对于铜，城市固体废物中水分的存在抑制了氧化物的挥发，并增加了氯化物和金属物种的挥发，而相比之下，城市固体废物中水分的存在总是抑制铅和锌的挥发，无论使用何种化学形式。提出了在焚烧过程中控制不同化学形式挥发行为的化学机制。水解、水解产物的脱水、升华、挥发性较低的物质向挥发性较高的物质的化学转化或相反过程，可能参与并影响城市固体废物中重金属的挥发。
