Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, Jiangsu Province, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, Jiangsu Province, China; Xinan Technology University, Mianyang 621010, Sichuan Province, China.
Sci Total Environ. 2023 Sep 1;889:164243. doi: 10.1016/j.scitotenv.2023.164243. Epub 2023 May 16.
The simultaneous removal of hexavalent chromium (Cr(VI)) and Trichloroethylene (TCE) is facing great challenges, and the influences of the biochar on their removal by nanoscale zero-valent iron (nZVI) are poorly understood and seldom addressed in the literature. The rice straw pyrolysis at 700 °C (RS700) and their supported nZVI composites were investigated on the removal of Cr(VI) and TCE by batch experiments. The surface area and chromium bonding state of biochar supported nZVI with and without Cr(VI)-TCE loading were analyzed by Brunauer-Emmett-Teller analysis and X-ray photoelectron spectroscopy. In single pollutants system, the highest removal amounts of Cr(VI) and TCE were observed in RS700-HF-nZVI (76.36 mg/g) and RS700-HF (32.32 mg/g), respectively. The Cr(VI) removal was attributed to the reduction by Fe(II) with the adsorption by biochar primarily controlling the TCE removal. The mutual inhibition was revealed in simultaneous removal of Cr(VI) and TCE, in which the reduction of Cr(VI) was decreased due to the adsorption of Fe(II) by biochar, while the TCE adsorption was primarily inhibited owing to the blockage of surface pores of biochar supported nZVI by chromium‑iron oxides. Therefore, biochar supported nZVI could be potentially used for the combined contaminated groundwater remediation, but the mutual inhibition should be evaluated.
同时去除六价铬（Cr(VI)）和三氯乙烯（TCE）面临巨大挑战，而生物炭对纳米零价铁（nZVI）去除它们的影响在文献中理解甚少，很少被提及。通过批量实验研究了在 700°C 下热解的水稻秸秆（RS700）及其负载的 nZVI 复合材料对 Cr(VI)和 TCE 的去除效果。通过比表面积和 Brünauer-Emmett-Teller 分析以及 X 射线光电子能谱分析了负载 Cr(VI)-TCE 前后生物炭负载 nZVI 的表面面积和铬键合状态。在单一污染物体系中，在 RS700-HF-nZVI（76.36 mg/g）和 RS700-HF（32.32 mg/g）中观察到 Cr(VI)和 TCE 的去除量最高。Cr(VI)的去除归因于 Fe(II)的还原，主要通过生物炭吸附来控制 TCE 的去除。在同时去除 Cr(VI)和 TCE 时，发现存在相互抑制作用，其中 Cr(VI)的还原因生物炭对 Fe(II)的吸附而降低，而 TCE 的吸附则主要因生物炭负载 nZVI 的表面孔被铬铁氧化物堵塞而受到抑制。因此，生物炭负载 nZVI 可潜在用于联合污染地下水修复，但应评估相互抑制作用。
