College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China.
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China.
Water Res. 2016 Sep 15;101:555-563. doi: 10.1016/j.watres.2016.06.006. Epub 2016 Jun 4.
Bromate (BrO3(-)), an oxyhalide disinfection by-product (DBP) in drinking water, has been demonstrated to be carcinogenic and genotoxic. In the current work, metallic Ag and reduced graphene oxide (RGO) co-modified BiVO4 was successfully synthesized by a stepwise chemical method coupling with a photo-deposition process and applied in the photo-reduction of BrO3(-) under visible light irradiation. In this composite, metallic Ag acted as an electron donor or mediator and RGO enhanced the BrO3(-) adsorption onto the surface of catalysts as well as an electron acceptor to restrict the recombination of photo-generated electron-hole pairs. The Ag@BiVO4@RGO composite exhibited greater photo-reduction BrO3(-) performance than pure BiVO4, Ag@BiVO4 and RGO@BiVO4 under identical experimental conditions: initial BrO3(-) concentration 150 μg/L, catalyst dosage 0.5 g/L, pH 7.0 and visible light (λ > 420 nm). The photoluminescence spectra (PL), electron-spin resonance (ESR), photocurrent density (PC) and electrochemical impedance spectroscopy (EIS) measurements indicated that the modified BiVO4 enhanced the photo-generated electrons and separated the electron-hole pairs. The photocatalytic reduction efficiency for BrO3(-) removal decreased with the addition of electron quencher K2S2O8, suggesting that electrons were the primary factor in this photo-reduction process. The declining photo-reduction efficiency of BrO3(-) in tap water should attribute to the consumption of photo-generated electrons by coexisting anions and the adsorption of dissolved organic matter (DOM) on graphene surface. The overall results indicate a promising application potential for photo-reduction in the DBPs removal from drinking water.
溴酸盐（BrO3(-)）是饮用水中的一种含氧卤化物消毒副产物（DBP），已被证明具有致癌性和遗传毒性。在本研究中，采用分步化学法结合光沉积法成功合成了金属 Ag 和还原氧化石墨烯（RGO）共修饰的 BiVO4，并将其应用于可见光照射下 BrO3(-)的光还原。在该复合材料中，金属 Ag 充当电子供体或介质，而 RGO 增强了 BrO3(-)在催化剂表面的吸附，并作为电子受体来限制光生电子-空穴对的复合。在相同的实验条件下，Ag@BiVO4@RGO 复合材料比纯 BiVO4、Ag@BiVO4 和 RGO@BiVO4 具有更好的光还原 BrO3(-)性能：初始 BrO3(-)浓度 150μg/L、催化剂用量 0.5g/L、pH 值 7.0 和可见光（λ>420nm）。光致发光光谱（PL）、电子自旋共振（ESR）、光电流密度（PC）和电化学阻抗谱（EIS）测试表明，修饰后的 BiVO4 增强了光生电子并分离了电子-空穴对。随着电子猝灭剂 K2S2O8 的加入，BrO3(-)的光催化还原效率降低，表明电子是该光还原过程中的主要因素。自来水中 BrO3(-)光还原效率的下降应归因于共存阴离子对光生电子的消耗以及溶解有机物（DOM）在石墨烯表面的吸附。总的来说，该结果表明光还原在饮用水中去除 DBPs 方面具有广阔的应用前景。
Zotero 插件