Triton X-100/正戊醇/环己烷微乳液条件下BiOBr制备及其光催化性能  

Preparation of BiOBr under Triton X-100/n-Pentanol/Cyclohexane Microemulsion and Its Photocatalytic Performance

作　　者：黑梦云 顾彦[2,3] 彭钦天 陈云龙[2] 李张丽 黄应平[2,3] Johnson DAVID 田海林 HEI Mengyun;GU Yan;PENG Qintian;CHEN Yunlong;LI Zhangli;HUANG Yingping;Johnson DAVID;TIAN Hailin(College of Biological&Pharmaceutical Sciences,China Three Gorges University,Yichang 443002,Hubei,China;Engineering Research Center of Eco-Environment in Three Gorges Reservoir Rerion of Ministry of Education,China Three Gorges University,Yichang 443002,Hubei,China;College of Hydraulic and Environmental Engineering,China Three Gorges University,Yichang 443002,Hubei,China)

机构地区：[1]三峡大学生物与制药学院,湖北宜昌443002 [2]三峡大学三峡库区生态环境教育部工程研究中心,湖北宜昌443002 [3]三峡大学水利与环境学院,湖北宜昌443002

出　　处：《武汉大学学报（理学版）》2021年第1期52-60,共9页Journal of Wuhan University:Natural Science Edition

基　　金：国家自然科学基金(21972073,21677086,21577077);湖北省引智项目(2019BJH004);湖北省创新群体滚动项目(2015CFA021);中国博士后基金(2018M640721);湖北省博士后基金(G83)。

摘　　要：以Triton X-100为表面活性剂,正戊醇为助表面活性剂,环己烷为连续油相,0.20 mol/L Bi(NO3)3·5H2O(NaBr)为水相,在环己烷/Triton X-100/正戊醇/水相(体积比20∶6∶4∶6)的微乳液介质条件下制备BiOBr(BiOBr-m)光催化剂。运用X射线衍射(XRD)、扫描电子显微镜(SEM)、比表面积及孔径分析仪(BET)、紫外-可见漫反射(UV-Vis DRS)等技术对样品的物理结构、吸附性能及光学性质进行表征。与水溶液介质中制备的BiOBr(BiOBr-h)相比,BiOBr-m具有较大的比表面积(13.40 m2/g)和孔径(13.65 nm),更利于污染物分子进入催化剂内部发生反应,具有更小的禁带宽度(2.75 eV),显著增强了对可见光的吸收。在可见光(≥420 nm)照射下,BiOBr-m对有机污染物罗丹明B(RhB)和无色小分子农药草甘膦(glyphosate)的反应速率常数分别是BiOBr-h的14.8倍和11.7倍。利用活性物种捕获实验对BiOBr-m降解机理进行研究,发现RhB和草甘膦在BiOBr-m催化剂界面降解的主要活性物种为超氧阴离子自由基和空穴。BiOBr-m催化剂在循环使用5次之后对RhB仍保持89%以上的脱色率,表现出较好的稳定性。With TritonX-100 as surfactant,n-pentanol as co-surfactant,cyclohexane as continuous oil phase,0.20 mol/L Bi(NO3)3·5H2O(NaBr)as water phase,BiOBr(denoted as BiOBr-m)was prepared under the condition of cyclohexane/TritonX-100/n-pentanol/water phase(volume ratio 20∶6∶4∶6)in a microemulsion medium.The physical structure,adsorption characteristics and optical properties of the obtained samples were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM),specific surface area and pore size analyzer(BET)and ultraviolet-visible diffuse reflection(UV-Vis DRS)respectively.Compared with BiOBr(denoted as BiOBr-h)prepared in aqueous medium,BiOBr-m has a larger specific surface area(13.40 m2/g),and pore size(13.65 nm),indicating that more pollutant molecules could react with photocatalysts.More importantly,BiOBr-m markedly enhanced visible light absorption and photocatalytic activity,and the band gap width is reduced from 2.86 eV to 2.75 eV.Under visible light(≥420 nm),the reaction rate constants of BiOBr-m for the organic pollutants Rhodamine B(RhB)and colorless small molecule glyphosate pesticide are 14.8 times and 11.7 times as much as that of BiOBr-h respectively,indicating that BiOBr-m has higher photocatalytic activity than BiOBr-h.The degradation mechanism of BiOBr-m was studied using the active species capture experiment,and it was found that the main active species for degradation of RhB and glyphosate at the interface of BiOBr-m catalyst were superoxide anion radicals and photogenerated holes.The BiOBr-m catalyst still maintains a decolorization rate of over 89% for RhB after being recycled for 5 times,indicating that its stability is good.

关 键 词：微乳液 BiOBr 光催化降解 罗丹明B 草甘膦 

分 类 号：O643[理学—物理化学]