College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
College of Environmental Science and Engineering, Hunan University, Lushan South Road, Yuelu District, Changsha 410082, China.
J Environ Sci (China). 2021 Sep;107:194-204. doi: 10.1016/j.jes.2021.02.006. Epub 2021 Feb 24.
Cr(VI) is a common heavy metal ion, which will seriously harm human body and environment. Therefore, the removal of Cr(VI) has become an attractive topic. In this work, cinder was used as a raw material to synthesize a nanoneedle material: γ-(AlOOH@FeOOH) (γ-Al@Fe). The physicochemical properties of γ-Al@Fe were thoroughly characterized, and its effectiveness as a catalyst for photocatalytic reduction of Cr(VI) was evaluated. The results showed that Cr(VI) could be efficiently reduced by γ-Al@Fe in the presence of tartaric acid (TA) under visible light. The variable factors on the reaction were investigated in detail, and the results showed that under optimal conditions (γ-Al@Fe 0.4 g/L, TA 0.6 g/L, pH 2), Cr(VI) was completely reduced within 7 min. Besides, scavenger experiments and EPR proved that O and CO played a significant role in the photocatalytic reduction of Cr(VI). TA acts as a sacrificial agent to trap the holes and generate strong reducing free radicals: CO. Dissolving O could react with electrons to generate O. This work discussed the performance and mechanism of photocatalytic reduction of Cr(VI) in detail, which provided a new idea for the resource utilization of solid waste and the treatment of heavy metal sewage.
六价铬（Cr(VI)）是一种常见的重金属离子，会对人体和环境造成严重危害。因此，去除 Cr(VI)已成为一个热门话题。本工作以炉渣为原料合成了一种纳米针状材料：γ-(AlOOH@FeOOH)（γ-Al@Fe）。对γ-Al@Fe 的物理化学性质进行了深入表征，并评估了其作为光催化还原 Cr(VI)催化剂的效果。结果表明，在可见光存在下，γ-Al@Fe 可在酒石酸（TA）存在下有效还原 Cr(VI)。详细考察了反应的可变因素，结果表明，在最佳条件（γ-Al@Fe 0.4 g/L，TA 0.6 g/L，pH 2）下，Cr(VI)可在 7 min 内完全还原。此外，猝灭实验和 EPR 证明，O 和 CO 在 Cr(VI)的光催化还原中起重要作用。TA 作为牺牲剂可捕获空穴并生成强还原自由基：CO。溶解氧可与电子反应生成 O。本工作详细讨论了光催化还原 Cr(VI)的性能和机理，为固体废物的资源化利用和重金属污水的处理提供了新思路。
