Hubei Key Laboratory of Mineral Resources Processing and Environment, State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, 122 Luoshi Road, Wuhan, Hubei430070, China.
Environ Sci Technol. 2022 Dec 20;56(24):18008-18017. doi: 10.1021/acs.est.2c06571. Epub 2022 Dec 8.
Photo-Fenton-like reaction based on oxalic acid (OA) activation is a promising method for the fast degradation of pollutants due to the low cost and safety. Hence, the magnetic recyclable greigite (FeS) with the exposed {011} facet (FS-011) was prepared using a facile one-pot hydrothermal method and activated OA under visible light irradiation for pollutant removal, in which the removal efficiency values of FS-011 for metronidazole (MNZ) and hexavalent chromium were 2.02 and 1.88 times higher than that of FeS with the exposed {112} facet, respectively. Density functional theory calculations revealed that OA was more easily adsorbed by the {011} facet of FeS than by the {112} facet, and the in situ-generated HO preferred to diffuse away from the active sites of the {011} facet of FeS than from that of the {112} facet, which was conducive to the continuous adsorption and efficient activation of OA. Moreover, the analyses of Fukui index and dual descriptor confirmed the degradation mechanism that the imidazole ring of MNZ was easy to be attacked by electrophilic species, while the amino group of MNZ was easy to be attacked by nucleophilic species. These findings deeply analyzed the mechanism of enhanced OA activation by facet engineering and consolidated the theoretical basis for practical application of Fenton-like reactions.
基于草酸（OA）活化的类 Fenton 光催化反应由于成本低、安全性好，是一种快速降解污染物的有前途的方法。因此，采用简便的一步水热法制备了暴露{011}面的磁性可回收针铁矿（FeS）（FS-011），并在可见光照射下将其用于去除污染物，其中 FS-011 对甲硝唑（MNZ）和六价铬的去除效率分别比暴露{112}面的 FeS 高 2.02 和 1.88 倍。密度泛函理论计算表明，OA 更容易被 FeS 的{011}面吸附，而不是{112}面吸附，并且原位生成的 HO 更喜欢从 FeS 的{011}面的活性位点扩散出来，而不是从{112}面的活性位点扩散出来，这有利于 OA 的连续吸附和有效活化。此外，福井指数和双描述符的分析证实了降解机制，即 MNZ 的咪唑环容易被亲电物质攻击，而 MNZ 的氨基容易被亲核物质攻击。这些发现深入分析了通过晶面工程增强 OA 活化的机制，为类 Fenton 反应的实际应用提供了理论基础。
