School of Metallurgy and Environment, Central South University, Changsha, 410083, PR China.
School of Metallurgy and Environment, Central South University, Changsha, 410083, PR China; Chinese National Engineering Research Centre for Control & Treatment of Heavy Metal Pollution, Changsha, 410083, PR China.
Environ Pollut. 2022 Apr 1;298:118855. doi: 10.1016/j.envpol.2022.118855. Epub 2022 Jan 17.
Strongly alkaline high Cr(VI) contaminated (SAHCR) soil poses a high risk to the environment and public health, yet lacks rapid and efficient remediation technology. In this study, a novel approach combining microwave irradiation with zerovalent iron/pyrite (FeS/ZVI) was developed for the remediation of SAHCR soil. The results indicated that fast and efficient remediation of the SAHCR soil was achieved by microwave irradiation-assisted FeS/ZVI, with 99.9% of removal rate of Cr(VI) within 10 min, and Cr(VI) concentration from 3900.8 plummeted to 2.38 mg kg. The data of Cr(VI) reduction kinetics at different temperatures indicated that the activation energies (E) for microwave-FeS/ZVI system was 27.4 kJ mol, 28.5% lower than that without microwave irradiation, suggesting that in addition to the heating effect of microwave, the accelerated Cr(VI) reduction also comes from the catalytic effect of "hot spots" on FeS/ZVI under microwave irradiation. Furthermore, it was demonstrated that microwave irradiation promoted the transformation of reduced Cr(III) into the stable FeCrO mineral and the excellent long-term stability of the remediated SAHCR soil. These findings can provide a perspective for advanced remediation of the difficult-to-treat SAHCR soil by the synergism of microwave irradiation with the iron-sulfur based reducing materials.
强碱性高六价铬污染（SAHCR）土壤对环境和公众健康构成高风险，但缺乏快速高效的修复技术。本研究开发了一种将微波辐射与零价铁/黄铁矿（FeS/ZVI）相结合的新型方法，用于修复 SAHCR 土壤。结果表明，微波辐射辅助 FeS/ZVI 可快速高效地修复 SAHCR 土壤，在 10 分钟内去除率达到 99.9%，Cr(VI)浓度从 3900.8 骤降至 2.38 mg kg。不同温度下 Cr(VI)还原动力学数据表明，微波-FeS/ZVI 体系的活化能（E）为 27.4 kJ mol，比无微波辐照时低 28.5%，这表明除了微波的加热效应外，加速 Cr(VI)还原还来自于微波辐照下“热点”对 FeS/ZVI 的催化作用。此外，还证明了微波辐射促进了还原态 Cr(III)向稳定的 FeCrO 矿物的转化，以及修复后的 SAHCR 土壤的优异长期稳定性。这些发现为利用微波辐射与铁硫基还原材料的协同作用对难处理的 SAHCR 土壤进行高级修复提供了一个视角。
