Gao Feilong, Ahmad Shakeel, Tang Jingchun, Zhang Chengfang, Li Song, Yu Chen, Liu Qinglong, Sun Hongwen
Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
Sci Total Environ. 2022 Jun 20;826:153960. doi: 10.1016/j.scitotenv.2022.153960. Epub 2022 Feb 19.
Sulfidated nano zerovalent iron (S-nZVI) is reported to be effective in removal of aqueous organic contaminants. However, little is known about its potential use in reductive degradation of soil-sorbed contaminants. In this study, biochar (BC) supported S-nZVI (S-nZVI@BC) was successfully synthesized through sulfidation and carbon loading modification, which effectively combined the solubilization characteristics of BC and high reduction characteristics of S-nZVI. Transmission electron microscopy (TEM) with an energy-dispersive X-ray spectroscopy (EDS) analysis suggested that sulfur and iron were evenly distributed throughout BC matrix. The degradation of nitrobenzene (NB) in soil was achieved more efficiently with the as-synthesized S-nZVI@BC composites. Results indicated that S-nZVI@BC with S-nZVI/BC mass ratio of 3:1, dosage of 10 mg/g exhibited superior NB removal (98%) and aniline (AN) formation (90%) efficiency within 24 h without formation of other intermediates, higher than those of S-nZVI. Meanwhile, the surface FeS layer enhanced the antioxidant capacity of S-nZVI@BC and participated in the reduction of NB. The soil-sorbed NB decreased from 14% to 1.4%, indicating that the addition of BC played an important role in solubilization of NB from soil. Solubilization-reduction was the dominant mechanism for NB removal. This research indicated that S-nZVI@BC held the potential to enhance in-situ remediation of NB-contaminated soil.
据报道，硫化纳米零价铁（S-nZVI）可有效去除水中的有机污染物。然而，关于其在还原降解土壤吸附污染物方面的潜在用途却知之甚少。在本研究中，通过硫化和碳负载改性成功合成了生物炭（BC）负载的S-nZVI（S-nZVI@BC），它有效地结合了BC的增溶特性和S-nZVI的高还原特性。带有能量色散X射线光谱（EDS）分析的透射电子显微镜（TEM）表明，硫和铁均匀分布在整个BC基质中。合成的S-nZVI@BC复合材料能更有效地实现土壤中硝基苯（NB）的降解。结果表明，S-nZVI/BC质量比为3:1、用量为10 mg/g的S-nZVI@BC在24小时内表现出优异的NB去除率（98%）和苯胺（AN）生成效率（90%），且未形成其他中间体，高于S-nZVI。同时，表面FeS层增强了S-nZVI@BC的抗氧化能力并参与了NB的还原。土壤吸附的NB从14%降至1.4%，表明BC的添加在从土壤中增溶NB方面发挥了重要作用。增溶-还原是NB去除的主要机制。本研究表明，S-nZVI@BC在增强原位修复NB污染土壤方面具有潜力。
