摘要
随着工业和城市化进程的不断发展,重金属污染问题日益凸显。这就对现场适用且行之有效的稳定/固化(stabilization/solidification,S/S)方法提出了要求。因此,研究了强酸(pH=3)、弱酸(pH=5)和中性(pH=7)环境下活性氧化镁(MgO)碳化固化污染土中锌的长期淋滤行为和淋滤机制。采用半动态淋滤试验方法,根据有效扩散系数De和可滤出性指标Lx评价了在不同污染浓度、活性氧化镁掺量及碳化时间下S/S处理的效果。结果表明,强酸性(pH=3)环境中锌离子的溶出量明显大于弱酸性(pH=5)和中性(pH=7)环境,均比未处理污染土样低4~5个数量级。碳化处理后土体的De均小于3×10^(-13)m^(2)/s,Lx均超过9,满足了污染场地控制再利用的条件。在长时间的酸侵蚀下,碳化后的锌最终通过溶解作用溶出。基于这些研究结果,活性氧化镁碳化方法修复锌污染土为重金属污染土地资源的安全处理和再利用奠定了坚实的基础。
Heavy metal contamination is a growing problem with increasing industrial and urbanization processes.This has created a requirement for field-applicable and effective stabilization/solidification(S/S)methods.Therefore,the long-term leaching behavior and leaching mechanism of zinc from activated magnesium oxide(MgO)carbonation-cured contaminated soils in strong(pH=3),weak(pH=5),and neutral(pH=7)environments were investigated.The semi-dynamic leaching test method was used to evaluate the effect of S/S treatment under different pollution concentrations,active MgO dosages,and carbonation times by effective diffusion coefficient(De)and leachability index(Lx).The results showed that the dissolution of Zn ions in the strongly acidic(pH=3)environment was significantly greater than that in the weakly acidic(pH=5)and neutral(pH=7)environments,both of which were 4−5 orders of magnitude lower than that in the untreated contaminated soil samples.The De of the carbonation-treated soils were all less than 3×10^(−13) m^(2)/s,and the Lx were all more than 9,fulfilling the condition of controlling the contaminated site underutilization.Under prolonged acid attack,the carbonated Zn was eventually leached out by dissolution.Based on these findings,the remediation of Zn-contaminated soils by the activated MgO carbonation method lays a solid foundation for safely treating and reusing heavy metal-contaminated land resources.
作者
宋宇
丁松
陈凯斌
江嘉辉
杨承琨
陈玉洁
张建伟
郑俊杰
SONG Yu;DING Song;CHEN Kai-bin;JIANG Jia-hui;YANG Cheng-kun;CHEN Yu-jie;ZHANG Jian-wei;ZHENG Jun-jie(School of Civil and Construction Engineering,Guilin University of Technology,Guilin,Guangxi 541000,China;Key Laboratory of Karst Dynamics,Ministry of Natural Resources&Guangxi,Institute of Karst Geology,Chinese Academy of Geological Sciences,Guilin,Guangxi 541004,China;School of Civil Engineering and Architecture,Henan University,Kaifeng,Henan 475004,China;School of Civil Engineering,Wuhan University,Wuhan,Hubei 430072,China)
出处
《岩土力学》
北大核心
2025年第S1期92-105,120,共15页
Rock and Soil Mechanics
基金
国家自然科学基金(No.42262030)
广西岩溶动力学重大科技创新基地开放课题(No.KDL&Guangxi202303)
河南省科技研发计划联合基金(No.225200810005)
广西岩土力学与工程重点实验室开放课题(No.桂科岩2023-XT-02)
关键词
碳化作用
活性氧化镁
半动态淋滤试验
有效扩散系数
可滤出性指标
carbonation
activated magnesium oxide
semi-dynamic leaching test
effective diffusion coefficient
leachability index
