Zou Zhenjie, Qin Yinghong, Zhang Tongsheng, Tan Kanghao
College of Civil Engineering and Architecture, Guangxi University, 100 University Road, Nanning, Guangxi, 530004, China.
School of Materials Science and Engineering, South China University of Technology, 510640, Guangzhou, China.
J Environ Manage. 2023 Dec 15;348:119315. doi: 10.1016/j.jenvman.2023.119315. Epub 2023 Oct 14.
The effectiveness of cement-based solidification for remediating heavy metal-contaminated soil diminishes at high levels of contamination. To overcome this limitation, the potential of a biochar-cement composite curing agent to enhance the properties of Pb contaminated soil was investigated in this study. The permeability, unconfined compressive strength (UCS), and leaching characteristics of the biochar-cement composite material were assessed under varying biochar contents. The results revealed that the addition of 1-5 wt% biochar in cement significantly improved the UCS of the solidified soil. However, excessive biochar contents had a detrimental effect on the strength of samples. Additionally, the incorporation of 3.0% biochar reduced the hydraulic conductivity and porosity to 7.75 × 10 cm/s and 43.12%, respectively. Moreover, the biochar-cement composite material exhibited remarkable efficiency in treating highly concentrated Pb contaminated soil, with leaching concentration decreasing significantly with increasing biochar content, falling below the Chinese hazardous waste identification standard. Overall, the utilization of a biochar-cement composite curing agent in the solidification of heavy metal-contaminated soil could be considered a promising subgrade filler technique.
基于水泥的固化法修复重金属污染土壤的有效性在高污染水平下会降低。为克服这一局限性，本研究考察了生物炭-水泥复合固化剂改善铅污染土壤性能的潜力。在不同生物炭含量下评估了生物炭-水泥复合材料的渗透性、无侧限抗压强度（UCS）和浸出特性。结果表明，在水泥中添加1-5 wt%的生物炭可显著提高固化土壤的UCS。然而，生物炭含量过高对样品强度有不利影响。此外，掺入3.0%的生物炭可分别将水力传导率和孔隙率降低至7.75×10 cm/s和43.12%。此外，生物炭-水泥复合材料在处理高浓度铅污染土壤方面表现出显著效果，浸出浓度随生物炭含量增加而显著降低，低于中国危险废物鉴别标准。总体而言，生物炭-水泥复合固化剂用于重金属污染土壤的固化可被视为一种有前景的路基填料技术。
