Mercury (Hg) contamination in soil has been a worldwide environmental concern. We prepared and investigated a novel MgAl layered double hydroxide supported iron sulfide composite (FeS@MgAl-LDH) for immobilization of mercury in two high-profile Hg-contaminated field soils (TJ soil represents freshly Hg-contaminated soil and GY soil represents historically aged Hg-contaminated soil). Amending the two soils with FeS@MgAl-LDH effectively immobilized mercury. The addition of 0.02% of FeS@MgAl-LDH immobilized 97.0% of mercury in TJ soil within 80 d. Similarly, the addition of 0.05% of FeS@MgAl-LDH immobilized 84.9% of mercury in GY soil. Increasing the FeS@MgAl-LDH dosage enhanced the immobilization efficiency. Increasing the dosage from 0.02% to 1% boosted the Hg immobilization efficiency in TJ soil from 97.0% to 99.4%. Increasing the dosage from 0.05% to 1% enhanced the Hg immobilization efficiency in GY soil from 84.9% to 86.2%. FeS@MgAl-LDH reacted with Hg via chemical precipitation and surface complexation, and transformed Hg from more available Hg fractions (exchangeable and carbonate bound fractions) into less available forms (organic and residual fractions), thus, reducing the environmental risk of mercury. The addition of FeS@MgAl-LDH inhibited the production of methylmercury while enhanced the soil enzyme activities. This study proves the potential and feasibility of FeS@MgAl-LDH to effectively immobilize mercury in soil.

中文翻译：

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Mg2Al层状双氢氧化物负载硫化铁复合材料化学稳定污染土壤中的汞

土壤中的汞（Hg）污染一直是世界范围内的环境问题。我们制备并研究了一种新型 MgAl 层状双氢氧化物负载的硫化铁复合材料 (FeS@MgAl-LDH)，用于在两种高浓度汞污染的田间土壤中固定汞（TJ 土壤代表新鲜的汞污染土壤，GY 土壤代表历史老化的土壤）汞污染的土壤）。用 FeS@MgAl-LDH 改良两种土壤可有效固定汞。添加0.02%的FeS@MgAl-LDH在80 d内固定了TJ土壤中97.0%的汞。同样，添加0.05%的FeS@MgAl-LDH固定了GY土壤中84.9%的汞。增加 FeS@MgAl-LDH 剂量可提高固定化效率。将剂量从0.02%增加到1%，TJ土壤中汞的固定效率从97.0%提高到99.4%。当剂量从0.05%增加到1%时，GY土壤中汞的固定效率从84.9%提高到86.2%。 FeS@MgAl-LDH通过化学沉淀和表面络合与Hg反应，将Hg从更容易利用的Hg组分（可交换的和碳酸盐结合的组分）转化为不易利用的形式（有机和残留组分），从而降低了汞的环境风险。 FeS@MgAl-LDH的添加抑制了甲基汞的产生，同时增强了土壤酶活性。这项研究证明了FeS@MgAl-LDH有效固定土壤中汞的潜力和可行性。