Li Xiaojun, Yang Ruizhi, Li Hao, Yi Hao, Jing Hongjun
Xi'an University of Science and Technology, Xi'an 710054, China.
Materials (Basel). 2021 Sep 1;14(17):4999. doi: 10.3390/ma14174999.
In order to solve the shortcomings of the traditional curing agent in the treatment of composite heavy-metal-contaminated soil with the solidification and stabilization method, a new type of cementing material A was used as a curing agent, and the Pb, Cd, Cu composite heavy-metal-contaminated soil was artificially prepared to carry out an experimental study on solidification and stabilization (SS) restoration by the mechanical properties test, leaching performance test, and microscopic test. The results show that in the range of test dosage, with the increase in the curing agent content, the unconfined compressive strength of the solidified body increased, and the resistance to deformation was enhanced. From the perspective of leaching characteristics, the new curing agent A had an excellent curing effect on the composite heavy-metal-contaminated soil. To achieve safe disposal, a curing agent content of 10% applies only for the soil heavily contaminated by heavy metals. The curing agent A could significantly reduce the content of acid-extractable heavy metals after solidifying the heavy metal Pb, Cd, and Cu composite contaminated soil and effectively converted it into a residue state. The solidified phase contained hydrated products such as calcium silicate hydrate (CSH) and ettringite (AFt). These hydrated products can inhibit the leaching performance of heavy metal ions through adsorption, encapsulation, and ion exchange. The study provides a feasible method and reference for the solidification, restoration, and resource utilization of heavy-metal-contaminated soil in the subgrade.
为解决传统固化剂在采用固化稳定化法处理复合重金属污染土壤时存在的不足，选用新型胶凝材料A作为固化剂，人工制备铅、镉、铜复合重金属污染土壤，通过力学性能试验、浸出性能试验和微观试验对其进行固化稳定化（SS）修复试验研究。结果表明，在试验剂量范围内，随着固化剂含量的增加，固化体的无侧限抗压强度提高，抗变形能力增强。从浸出特性来看，新型固化剂A对复合重金属污染土壤具有良好的固化效果。为实现安全处置，仅对重金属重度污染土壤适用10%的固化剂含量。固化剂A固化重金属铅、镉、铜复合污染土壤后，可显著降低酸可提取态重金属含量，并有效将其转化为残渣态。固化相包含水化硅酸钙（CSH）和钙矾石（AFt）等水化产物。这些水化产物可通过吸附、包裹和离子交换抑制重金属离子的浸出性能。该研究为路基中重金属污染土壤的固化、修复及资源利用提供了可行方法和参考。
