Zhang Yan, Jiang Jianguo, Chen Maozhe
Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China.
J Environ Sci (China). 2008;20(11):1398-402. doi: 10.1016/s1001-0742(08)62239-1.
At present, all kinds of municipal solid waste incineration (MSWI) fly ash stabilization technology has been reported and successfully applied in many countries. However, leaching procedures are very different that the technologies lack uniform standard, and it is even impossible to predict the long-term stabilization. Geochemical model can explain the environmental stabilization based on chemical phase and thermodynamic crystal structure, and it is also able to guide the development of environment-friendly stabilization technology and choosing of chemical agents. Both experiment analysis and geochemical modeling were used to study the correlation between leaching behavior of MSWI fly ash and variation of pH. Dissolution/precipitation mechanism was applied in the simulation. The result indicated that the pH-dependent leaching behavior predicted by Visual MINTEQ is well in agreement with the result of pH-dependent test. pH value of leachate can significantly change the leaching behavior of MSWI fly ash. The leaching behavior of heavy metals for Pb and Cd is controlled by dissolution/precipitation mechanism, whereas for Zn and Ni, it is effected by surface adsorption reaction over a special extent of pH value.
目前，各种城市固体废弃物焚烧（MSWI）飞灰稳定化技术已被报道，并在许多国家成功应用。然而，浸出程序差异很大，这些技术缺乏统一标准，甚至无法预测长期稳定性。地球化学模型可以基于化学相和热力学晶体结构解释环境稳定性，还能够指导环保稳定化技术的发展以及化学药剂的选择。采用实验分析和地球化学建模来研究MSWI飞灰浸出行为与pH值变化之间的相关性。在模拟中应用了溶解/沉淀机制。结果表明，Visual MINTEQ预测的pH值依赖性浸出行为与pH值依赖性测试结果吻合良好。渗滤液的pH值可显著改变MSWI飞灰的浸出行为。Pb和Cd等重金属的浸出行为受溶解/沉淀机制控制，而Zn和Ni在特定pH值范围内则受表面吸附反应影响。
