Jiangsu Key Laboratory of Urban Underground Engineering & Environmental Safety, Institute of Geotechnical Engineering, Southeast University, Nanjing 211189, China.
Postdoctoral Researcher, Jiangsu Province Key Laboratory of Environmental Engineering, Jiangsu, Provincial Academy of Environmental Science, Nanjing 210036, China.
Sci Total Environ. 2022 Nov 20;848:157646. doi: 10.1016/j.scitotenv.2022.157646. Epub 2022 Jul 27.
Ex-situ stabilization for As and Sb co-contaminated soil was conducted through an iron-based stabilizer, PFSC (a mixture of polymerized ferric sulfate (PFS) and hydrated lime (Ca(OH)) with a dry mass ratio of 2:1). After field aging for one week, the stabilized contaminated soil was subjected to a horizontal vibration leaching test (HJ 557), Wenzel's sequential extraction, and a semi-dynamic leaching test (ANS 16.1). By assessing the cumulative fractions of As and Sb, the observed diffusion coefficients (D) and leachability indices (LX) of metalloids released from the soil specimens were calculated. The PFSC ex-situ stabilization was effective to immobilize metalloids, and the As and Sb leached concentrations of stabilized contaminated soil samples were lower than remediation targets. Nonspecifically bound As and Sb in the stabilized contaminated soil samples decreased from 4.5 - 9.2 % to 1.5-2.5 % and from 2.2 - 5.8 % to 1.1-1.5 %, respectively. The mechanisms controlling the leaching behaviors of As and Sb included wash-off and diffusion and they were changed with the leaching interval. The mean D of As and Sb released from stabilized contaminated soil specimen were 3.46 × 10 and 2.99 × 10 cm s, in the which were two orders of magnitude lower than that of untreated contaminated soil specimen. The mean LX of stabilized contaminated soil specimen for As and Sb releases were 11.40 and 12.83, respectively, indicating that the stabilized contaminated soil was acceptable for "controlled utilization".
采用铁基稳定剂 PFSC（聚合硫酸铁（PFS）和熟石灰（Ca（OH））的混合物，干质量比为 2:1）对砷和锑共存污染土壤进行了异位稳定化。经过一周的现场老化后，对稳定化污染土壤进行了水平振动浸出试验（HJ 557）、Wenzel 连续提取和半动态浸出试验（ANS 16.1）。通过评估砷和锑的累积分数，计算了从土壤样品中释放的类金属的观察扩散系数（D）和浸出指数（LX）。PFSC 异位稳定化对类金属具有有效固定作用，稳定化污染土壤样品中砷和锑的浸出浓度低于修复目标。稳定化污染土壤样品中非特异性结合的砷和锑分别从 4.5-9.2%降至 1.5-2.5%和从 2.2-5.8%降至 1.1-1.5%。控制砷和锑浸出行为的机制包括冲刷和扩散，它们随着浸出间隔而变化。从稳定化污染土壤样品中释放的砷和锑的平均 D 分别为 3.46×10 和 2.99×10 cm/s，均低于未处理污染土壤样品的两个数量级。稳定化污染土壤样品的砷和锑释放平均 LX 分别为 11.40 和 12.83，表明稳定化污染土壤可用于“受控利用”。
