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原位吸附技术修复六价铬污染土壤

In situ Adsorption Technology for Remediation of Cr(Ⅵ) Contaminated Soil

  • 摘要: 常见六价铬Cr(Ⅵ)污染场地修复技术如客土法、还原法、固化法、生物法等存在成本高、效率低及Cr(Ⅵ)被二次氧化等缺点。理想修复技术应能快速、低成本地将铬元素(Cr)从土壤中彻底去除。本文将聚吡咯(PPy)通过原位聚合的方式负载在凹凸棒土(ATP)表面,制备了以PPy为“壳”和以ATP为“核”的ATP/PPy复合材料,ATP/PPy对Cr(Ⅵ)的最大吸附容量为185.19mg/g,吸附机理包括静电引力、螯合、还原与离子交换等。将ATP/PPy嵌入土壤中,利用Cr(Ⅵ)在土壤中的纵向迁移及横向浓度差渗透,可实现对土壤中Cr(Ⅵ)的原位吸附。实验考察了模拟降雨量、土壤pH、土壤容重、土壤有机质含量等因素对土壤中Cr(Ⅵ)去除效率的影响。结果表明,当供试土壤中Cr(Ⅵ)浓度为30mg/kg,模拟降雨量为6mL/天,土壤有机质含量为7.6g/kg,土壤容重为1.22g/cm3,土壤pH为5.86时,第35天时土壤滤液中Cr(Ⅵ)去除率为58.51%,土壤中Cr(Ⅵ)含量降低至2.97mg/kg,低于《土壤环境质量建设用地土壤污染风险管控标准(试行)》(GB36600—2018)中的建设用地第二类用地筛选值5.7mg/kg。该技术具有操作简单、经济环保、效率高、去除彻底等优势,可为污染场地的高效低成本治理提供新思路及技术支撑。

     

    Abstract: The commonly used remediation technologies for Cr(Ⅵ) contaminated soil, such as guest soil, reduction, solidification, microbiology, etc., have drawbacks such as high cost, slow efficiency, and secondary oxidation of Cr(Ⅵ). To solve these problems, a Cr(Ⅵ) contaminated soil remediation technology was developed. Firstly, polypyrrole was loaded onto the surface of attapulgite through in situ polymerization to prepare ATP/PPy adsorption material with PPy as the “shell” and ATP as the “core”. Then, ATP/PPy was embedded into the soil and remediate Cr(Ⅵ) contaminated soil through in situ adsorption technology. The experimental results show that under optimal conditions, the removal rate of Cr(Ⅵ) in soil filtrate was 58.51%, and the Cr(Ⅵ) content in the soil was reduced to 2.97mg/kg, which was lowered to below the screening value of 5.7mg/kg for the second category of development land in the Soil Environmental Quality: Risk Control Standard for Soil Contamination of Development Land (GB 36600—2018). Meanwhile, this technology has the advantages of simple operation, economic and environmental protection, high remediation efficiency, and thorough removal, and can be used for the remediation and treatment of actual Cr(Ⅵ) contaminated soil. The BRIEF REPORT is available for this paper at http://www.ykcs.ac.cn/en/article/doi/10.15898/j.ykcs.202307090090.

     

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