State Key Laboratory for Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, China.
School of Environmental Science and Engineering, Sun Yat-sen University, Guangdong, China.
J Hazard Mater. 2022 Jun 15;432:128683. doi: 10.1016/j.jhazmat.2022.128683. Epub 2022 Mar 12.
This study investigates the reaction between sulfidated nanoscale zero valent iron (S-nZVI) and Cr(VI) in the sludge system and explores the effect of S-nZVI on microbes. Results of the batch experiments indicated that the optimal Cr(VI) removal capacity (35.3 mg/g) was reached when the S/Fe ratio was at 0.05. It was about 20-time higher than that of nanoscale zero valent iron (nZVI) (<2.0 mg/g). However, the removal efficiency decreased as the S/Fe molar ratio further increased. Solid characterizations revealed that the S-nZVI consisted of a Fe core encapsulated by a flake FeS shell and had a similar "core-shell" structure to that of the nZVI. X-ray photoelectron spectroscopy (XPS) indicated that Cr(VI) was reduced to less toxic Cr(III). In addition, the 16 S rRNA gene and cryo-scanning electron microscopy (cryo-SEM) results showed S-nZVI mildly influenced the initial microbial diversity. Some microflora including Caldiserica, Planctomycetes were promoted, while others groups such as Actinobacteria, Bacteroidetes and Chloroflexi were inhibited: specifically, bacteria such as Proteobacteria (possibly related to sulfide oxidization) began to develop after the S-nZVI feeding. The high Cr(VI) removal efficiency and the mildly influenced microbial diversity make the usage of S-nZVI a win-win solution for Cr(VI) removal in sludge.
本研究考察了硫化纳米零价铁（S-nZVI）与污泥系统中 Cr(VI) 的反应，并探讨了 S-nZVI 对微生物的影响。批处理实验结果表明，当 S/Fe 比为 0.05 时，达到了最佳的 Cr(VI)去除容量（35.3 mg/g）。这大约是纳米零价铁（nZVI）的 20 倍（<2.0 mg/g）。然而，随着 S/Fe 摩尔比的进一步增加，去除效率降低。固体特性表明，S-nZVI 由一个被片状 FeS 壳包裹的 Fe 核组成，具有类似于 nZVI 的“核壳”结构。X 射线光电子能谱（XPS）表明 Cr(VI) 被还原为毒性较低的 Cr(III)。此外，16S rRNA 基因和冷冻扫描电子显微镜（cryo-SEM）结果表明，S-nZVI 轻微影响了初始微生物多样性。一些微生物群落，如 Caldiserica、Planctomycetes 得到了促进，而其他群落，如 Actinobacteria、Bacteroidetes 和 Chloroflexi 则受到了抑制：具体来说，一些细菌，如 Proteobacteria（可能与硫化物氧化有关），在 S-nZVI 投加后开始发育。高的 Cr(VI)去除效率和轻微影响的微生物多样性使得 S-nZVI 的使用成为污泥中 Cr(VI)去除的双赢解决方案。
