重金属在水泥基材料中的固化和浸出研究进展

Review on Stabilization and Leaching of Heavy Metals in Cementitious Materials

综述了重金属在水泥基材料中的固化和浸出机理、浸出影响因素和浸出试验方法。水泥基材料中固化重金属的机理主要是提供碱性环境促进重金属沉淀和吸附以及C-S-H凝胶和钙矾石对重金属的吸附、替代和封裹作用；重金属离子在弱酸性溶液中的浸出过程主要包括溶液中的酸迁移到液／固表面、酸迁移穿过浸出层、在浸出边界发生扩散控制的快速溶解反应、重金属穿过浸出层以及重金属穿过固腋表面到达溶液中；常用的浸出试验方法根据浸出溶液是否流动或者定期更换，可以概括为平衡试验和非平衡试验两大类。

This paper reviewed the stabilization and leaching mechanisms of heavy metals in cementitious materials, the factors affecting the leaching process, and the leaching test methods. It is indicated that the participation and adsorption of heavy metals are promoted by the alkaline environment provided by cementitious materials, and moreover, heavy metals can be absorbed, substituted, and encapsulated by C-S-H gel and ettringite. The leaching process of heavy metals in weak acid solutions is the mass transfer of acids across the solid/solution interface, through the leached layer, diffusion-controlled dissolution reactions at the leaching boundary, transport of metals through the leached layer, and finally across the solid/solution interface. In addition, the leaching test methods can be also classified as balance test and non-equilibrium test based on whether the leaching solution should flow or regularly renew.