Xie Lihong, Ma Qiyan, Chen Qingjun, Liu Yiyang, Guo Pengfei, Zhang Jinlan, Duan Guilan, Lin Aijun, Zhang Tingting, Li Shangyi
Department of Environmental Science and Engineering, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
China National Petroleum and Chemical Planning Institute, Beijing 100013, China.
J Environ Sci (China). 2025 Jan;147:474-486. doi: 10.1016/j.jes.2023.12.007. Epub 2023 Dec 18.
Nano zero-valent iron (nZVI) is widely used in soil remediation due to its high reactivity. However, the easy agglomeration, poor antioxidant ability and passivation layer of Fe-Cr coprecipitates of nZVI have limited its application scale in Cr-contaminated soil remediation, especially in high concentration of Cr-contaminated soil. Herein, we found that the carboxymethyl cellulose on nZVI particles could increase the zeta potential value of soil and change the phase of nZVI. Along with the presence of biochar, 97.0% and 96.6% Cr immobilization efficiency through CMC-nZVI/BC were respectively achieved in high and low concentrations of Cr-contaminated soils after 90-days remediation. In addition, the immobilization efficiency of Cr(VI) only decreased by 5.1% through CMC-nZVI/BC treatment after 10 weeks aging in air, attributing to the strong antioxidation ability. As for the surrounding Cr-contaminated groundwater, the Cr(VI) removal capacity of CMC-nZVI/BC was evaluated under different reaction conditions through column experiments and COMSOL Multiphysics. CMC-nZVI/BC could efficiently remove 85% of Cr(VI) in about 400 hr when the initial Cr(VI) concentration was 40 mg/L and the flow rate was 0.5 mL/min. This study demonstrates that uniformly dispersed CMC-nZVI/BC has an excellent remediation effect on different concentrations of Cr-contaminated soils.
纳米零价铁（nZVI）因其高反应活性而被广泛应用于土壤修复。然而，nZVI的Fe-Cr共沉淀物易团聚、抗氧化能力差以及存在钝化层，限制了其在铬污染土壤修复中的应用规模，尤其是在高浓度铬污染土壤中。在此，我们发现nZVI颗粒上的羧甲基纤维素可以增加土壤的zeta电位值并改变nZVI的相态。在生物炭存在的情况下，经过90天修复后，通过CMC-nZVI/BC在高浓度和低浓度铬污染土壤中分别实现了97.0%和96.6%的铬固定效率。此外，经过10周空气老化后，通过CMC-nZVI/BC处理，Cr(VI)的固定效率仅下降了5.1%，这归因于其强大的抗氧化能力。对于周围受铬污染的地下水，通过柱实验和COMSOL Multiphysics在不同反应条件下评估了CMC-nZVI/BC对Cr(VI)的去除能力。当初始Cr(VI)浓度为40 mg/L且流速为0.5 mL/min时，CMC-nZVI/BC在约400小时内可有效去除85%的Cr(VI)。本研究表明，均匀分散的CMC-nZVI/BC对不同浓度的铬污染土壤具有优异的修复效果。
