磺胺嘧啶(SDZ)是废水中常见的抗生素污染物。鉴于它作为环境污染物构成了风险,找到有效的治疗方法很重要。在本文中,制备了复合催化材料g-C3N4/Ag/γ-FeOOH,并对其降解性能进行了研究。g-C3N4/Ag/γ-FeOOH对SDZ的降解效果优于g-C3N4和γ-FeOOH。与不同的g-C3N4负载量和不同的催化剂剂量(5、10、25和50mg/L)相比,2mg/Lg-C3N4/Ag/γ-FeOOH,g-C3N4负载量为5.0wt%,对SDZ的降解促进作用最高,在600分钟时达到258.75%。此外,研究了催化剂的光催化增强机理。密度泛函理论(DFT)计算表明,光催化活性的增强与禁带的变窄和价带的局部电子密度有关。催化剂的带隙从2.7逐渐变窄到1.05eV,增加光吸收强度,扩大吸收边。状态密度图表明,界面处的局部共振可以有效地提高e-h对的分离效率。基于DFT计算推测了SDZ的四种退化路径。分析证实,SDZ的退化路径主要包括Smiles型重排,SO2挤出,和S-N键裂解过程。
Sulfadiazine (SDZ) is a common antibiotic pollutant in wastewater. Given that it poses a risk as an environmental pollutant, finding effective ways to treat it is important. In this paper, the composite catalytic material g-C3N4/Ag/γ-FeOOH was prepared, and its degradation performance was studied. g-C3N4/Ag/γ-FeOOH had a superior degradation effect on SDZ than g-C3N4 and γ-FeOOH. Compared with different g-C3N4 loadings and different catalyst dosages (5, 10, 25, and 50 mg/L), 2 mg/L g-C3N4/Ag/γ-FeOOH with a g-C3N4 loading of 5.0 wt% has the highest degradation promotion rate for SDZ, reaching up to 258.75% at 600 min. In addition, the photocatalytic enhancement mechanism of the catalyst was studied. Density functional theory (DFT) calculations indicated that the enhancement of photocatalytic activity was related to the narrowing of the forbidden band and the local electron density of the valence band. The bandgap of the catalyst was gradually narrowed from 2.7 to 1.05 eV, which can increase the light absorption intensity and expand the absorption edge. The density of states diagram showed that the local resonance at the interface could effectively improve the separation efficiency of e--h+ pairs. Four degradation paths of SDZ were speculated based on DFT calculations. The analysis confirmed that the degradation path of SDZ primarily included Smiles-type rearrangement, SO2 extrusion, and S-N bond cleavage processes.