Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 511443, China.
Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 511443, China.
J Hazard Mater. 2019 Jul 5;373:783-790. doi: 10.1016/j.jhazmat.2019.03.132. Epub 2019 Apr 1.
Mercury (Hg) contamination in soil is a paramount concern to the environment and public health. Yet, effective in situ remediation technologies have been lacking. In this study, a novel thiol-functionalized graphene oxide/Fe-Mn (SGO/Fe-Mn) composite was prepared and investigated for in situ immobilization of Hg in contaminated soil. Batch tests showed that application of SGO/Fe-Mn at doses of 0.4% and 0.8% effectively reduced HO, HSO and HNO, CHCOOH, and CaCl-extractable Hg by 90.3-98.9% and 96.5-98.9%, respectively, upon equilibrium after 72 d. An increasing of soil moisture content from 0 to 12.5% significantly enhanced the immobilization efficiency from 75.0% to 97.6%. XRD, FTIR, and XPS analyses suggested that the composite mainly immobilized Hg through surface complexation and chemical precipitation. Sequential extraction procedure demonstrated that the composite promoted the conversion of more accessible Hg (exchangeable and carbonate fractions) into the less accessible forms, i.e., oxides, organic matter, and residual fractions, resulting in substantially reduced environmental risk of Hg. The application of SGO/Fe-Mn enhanced soil cation exchange capacity, available N and K, and total organic carbon, and can be used to effectively improve soil properties. Moreover, immobilized Hg in soil by this composite remained stable over one year. The present study demonstrates the potential and viability of SGO/Fe-Mn for enhanced immobilization of Hg in soil and sediment.
土壤中汞（Hg）污染是环境和公众健康的首要关注点。然而，有效的原位修复技术一直缺乏。在这项研究中，制备了一种新型巯基功能化氧化石墨烯/Fe-Mn（SGO/Fe-Mn）复合材料，并研究了其在污染土壤中的原位固定化汞的能力。批量试验表明，在 72 天的平衡后，SGO/Fe-Mn 的应用剂量为 0.4%和 0.8%，可有效降低 HO、HSO 和 HNO、CHCOOH 和 CaCl 提取的 Hg，分别降低 90.3-98.9%和 96.5-98.9%。土壤含水量从 0 增加到 12.5%时，固定化效率从 75.0%显著提高到 97.6%。XRD、FTIR 和 XPS 分析表明，该复合材料主要通过表面络合和化学沉淀固定 Hg。连续提取程序表明，该复合材料促进了更易获得的 Hg（可交换和碳酸盐部分）向更难获得的形式（氧化物、有机物和残余物）的转化，从而大大降低了 Hg 的环境风险。SGO/Fe-Mn 的应用提高了土壤阳离子交换能力、有效氮和钾以及总有机碳，可有效改善土壤性质。此外，该复合材料固定在土壤中的 Hg 在一年多的时间内保持稳定。本研究表明，SGO/Fe-Mn 具有增强土壤和沉积物中 Hg 固定化的潜力和可行性。
