School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan, China.
School of Earth Science, China University of Geosciences, Wuhan, 430074, China.
Chemosphere. 2020 Sep;254:126879. doi: 10.1016/j.chemosphere.2020.126879. Epub 2020 Apr 23.
Soil is commonly polluted by chromium, and layered double hydroxides (LDHs) are widely used for chromium removal due to their strong adsorption capacity and the unique properties of their delaminated products. In this study, delaminated LDHs (S-Mg-LDH and S-Ca-LDH) and their original LDHs were used to remediate Cr(VI)-contaminated soil. A series of characterizations confirmed the successful synthesis of delaminated LDHs whose sheet structure was thinner with a greater surface energy than the original LDHs. The remediation results indicated that delaminated LDHs could more efficiently immobilize Cr(VI) in soil. The immobilization rate of S-Mg-LDH was 64.32%, while Mg-LDH was only 8.09%. However, at low dosages, the efficiency of S-Ca-LDH was 28.1% while Ca-LDH was 5.16%, but they had similar effects at high doses. Moreover, soil pH had little effect on their removal efficiencies. The toxicity characteristic leaching procedure (TCLP) results showed that the leaching of Cr(VI) in soil after treatment with S-Mg-LDH, S-Ca-LDH, Mg-LDH, and Ca-LDH was reduced by 75.43%, 72.43%, 86.55%, and 75.90%, respectively. The phytotoxicity tests of soil treated by S-Mg-LDH and S-Ca-LDH revealed that they effectively reduced the toxicity of chromium and lowered its bioaccumulation. Overall, this study confirms the feasibility of delaminated LDHs for Cr(VI) immobilization in soils.
土壤通常受到铬的污染，而层状双氢氧化物（LDHs）由于其强大的吸附能力和独特的层离产品特性而被广泛用于去除铬。在本研究中，使用层离 LDH（S-Mg-LDH 和 S-Ca-LDH）及其原 LDH 来修复含铬（VI）污染的土壤。一系列特性表明成功合成了层离 LDH，其片状结构比原 LDH 更薄，表面能更大。修复结果表明，层离 LDH 可更有效地将 Cr（VI）固定在土壤中。S-Mg-LDH 的固定率为 64.32%，而 Mg-LDH 仅为 8.09%。然而，在低剂量下，S-Ca-LDH 的效率为 28.1%，而 Ca-LDH 为 5.16%，但在高剂量下它们具有相似的效果。此外，土壤 pH 对它们的去除效率影响不大。毒性特征浸出程序（TCLP）结果表明，用 S-Mg-LDH、S-Ca-LDH、Mg-LDH 和 Ca-LDH 处理后，土壤中 Cr（VI）的浸出量分别减少了 75.43%、72.43%、86.55%和 75.90%。用 S-Mg-LDH 和 S-Ca-LDH 处理的土壤的植物毒性测试表明，它们有效降低了铬的毒性并降低了其生物累积。总体而言，本研究证实了层离 LDH 在土壤中固定 Cr（VI）的可行性。
