Pan Bao, Zhou Linxing, Qin Jiani, Wang Chuanyi, Ma Xingmao, Sharma Virender K
Key Laboratory of Chemical Additives for China National Light Industry, School of Chemistry and Chemical Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, PR China; Program for the Environment and Sustainability, Department of Environment and Occupational Health, School of Public Health, Texas A&M University, 212 Adriance Lab Rd., College Station, TX, 77843, USA.
Key Laboratory of Chemical Additives for China National Light Industry, School of Chemistry and Chemical Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, PR China.
Chemosphere. 2022 Nov;307(Pt 2):135886. doi: 10.1016/j.chemosphere.2022.135886. Epub 2022 Aug 1.
The treatment of recalcitrant micropollutants in water remains challenging. Ferrate(VI) (FeO, Fe(VI)) has emerged as a green oxidant to oxidize organic molecules, however, its reactivity with recalcitrant micropollutants are sluggish. Our results demonstrate enhanced oxidation of carbamazepine (CBZ) by three types of visible light-responsive graphitic carbon nitride (g-CN) photocatalyst in absence and presence of ferrate(VI) (FeO, Fe(VI)) under mild alkaline conditions. The g-CN photocatalysts were prepared by thermal process using urea, thiourea, and melamine and were named as CN-U, CN-T, and CN-M, respectively. The degradation efficiency of CBZ, in both visible light-g-CN and visible light-g-CN-FeO systems followed the order of CN-U > CN-T > CN-M. The mechanisms for this trend was elucidated by measuring physiochemical properties of the microstructures with various surface and analytical techniques. Results suggest the dominating role of specific surface area and surface delocalized electrons of microstructures in degrading CBZ. Crystallinity, morphology, and surface functional groups may not directly associate with CBZ degradation. The CN-U has higher specific surface area and surface delocalized electrons than CN-T and CN-M and therefore the highest degradation efficiency of CBZ. The surface electrons likely generated O and O in the visible light-g-CN system. The additional oxidants, Fe and Fe in the visible light-g-CN- FeO system led to higher degradation efficiency than the visible light-g-CN system. Results suggest that the surfaces of g-CN may be prepared preferentially with high levels of delocalized electrons at the surface of microstructures to enhance degradation of micropollutants.
水中难降解微污染物的处理仍然具有挑战性。高铁酸盐（VI）（FeO，Fe（VI））已成为一种用于氧化有机分子的绿色氧化剂，然而，它与难降解微污染物的反应活性较低。我们的结果表明，在温和碱性条件下，三种类型的可见光响应型石墨相氮化碳（g-CN）光催化剂在不存在和存在高铁酸盐（VI）（FeO，Fe（VI））的情况下，对卡马西平（CBZ）的氧化作用增强。g-CN光催化剂通过使用尿素、硫脲和三聚氰胺的热过程制备，分别命名为CN-U、CN-T和CN-M。在可见光-g-CN和可见光-g-CN-FeO体系中，CBZ的降解效率遵循CN-U > CN-T > CN-M的顺序。通过使用各种表面和分析技术测量微观结构的物理化学性质，阐明了这种趋势的机制。结果表明，微观结构的比表面积和表面离域电子在降解CBZ中起主导作用。结晶度、形态和表面官能团可能与CBZ降解没有直接关联。CN-U比CN-T和CN-M具有更高的比表面积和表面离域电子，因此对CBZ的降解效率最高。表面电子可能在可见光-g-CN体系中产生O和O。可见光-g-CN-FeO体系中的额外氧化剂Fe和Fe导致其降解效率高于可见光-g-CN体系。结果表明，g-CN的表面可能优先制备具有高水平微观结构表面离域电子的材料，以增强微污染物的降解。
