Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, Jiangsu Province, China.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, Jiangsu Province, China.
J Colloid Interface Sci. 2019 Jan 1;533:428-436. doi: 10.1016/j.jcis.2018.08.075. Epub 2018 Aug 23.
The potential of silicon-rich biochar and Pd were evaluated for the enhanced removal of Cr(VI) in solution by nanoscale zero-valent iron (nZVI) composites. The composition and structures of the nZVI, RS700-supported nZVI, and Pd-doped samples were analyzed by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy before and after reaction with Cr(VI). The amount of Cr(VI) removed by nZVI-RS700-Pd was considerably greater than the removal by nZVI, nZVI-Pd, or nZVI-RS700. This was mainly due to the enhanced reduction and adsorption of Cr(VI) by silicon-rich biochar and Pd. Silicon and Pd promoted the reduction of Cr(VI) due to the Fe crystallinity in the nZVI structures. The significantly decreased removal of Cr(VI) by the silicon-removed sample (nZVI-RS700 (-Si)) further confirmed that silicon played a significant role in the removal of Cr(VI). Cr(VI) adsorption was enhanced by the dispersion and adsorption of RS700. Following the reaction of RS700-supported nZVI with Cr(VI), ferrous chromite (FeCrO) was observed on the nZVI-RS700 composite surface. The formation of FeCrO can be attributed to the reduction of Cr(VI) by the nZVI and coprecipitation of chromium oxide with iron on the RS700 surface. Therefore, nZVI-RS700-Pd is a potential remediation reagent that can be used to effectively treat Cr(VI)-contaminated groundwater.
富硅生物炭和 Pd 的潜力被评估为通过纳米零价铁 (nZVI) 复合材料增强溶液中 Cr(VI) 的去除。在与 Cr(VI) 反应前后，通过扫描电子显微镜、傅里叶变换红外光谱、X 射线衍射和 X 射线光电子能谱分析了 nZVI、RS700 负载的 nZVI 和 Pd 掺杂样品的组成和结构。nZVI-RS700-Pd 去除的 Cr(VI) 量明显大于 nZVI、nZVI-Pd 或 nZVI-RS700 的去除量。这主要是由于富硅生物炭和 Pd 增强了 Cr(VI)的还原和吸附。硅和 Pd 促进了 Cr(VI)的还原，因为 nZVI 结构中的 Fe 结晶度。硅去除样品（nZVI-RS700(-Si)）对 Cr(VI)去除的显著降低进一步证实了硅在 Cr(VI)去除中发挥了重要作用。RS700 的分散和吸附增强了 Cr(VI)的吸附。在 RS700 负载的 nZVI 与 Cr(VI)反应后，在 nZVI-RS700 复合材料表面观察到亚铁铬矿（FeCrO）。FeCrO 的形成可归因于 nZVI 还原 Cr(VI)和 RS700 表面铁与铬氧化物的共沉淀。因此，nZVI-RS700-Pd 是一种潜在的修复试剂，可有效处理 Cr(VI)污染的地下水。
