锰掺杂BiOBr光催化降解头孢唑林研究  

Photocatalytic Degradation of Cefazolin in Aqueous Solution by Mn-doped BiOBr

作　　者：王夏伟 陈莹莹 黎敬芝[2,3] 施妍 黄应平 李瑞萍[2,3] WANG Xiawei;CHEN Yingying;LI Jingzhi;SHI Yan;HUANG Yingping;LI Ruiping(College of Biological&Pharmaceutical Science,China Three Gorges University,Yichang 443002,China;College of Hydraulic&Environmental Engineering,China Three Gorges University,Yichang 443002,China;Engineering Research Center for Ecological Environment of Ministry of Education,Three Gorges Reservoir Area(China Three Gorges University),Yichang 443002,China)

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

出　　处：《环境科学与技术》2022年第10期144-151,共8页Environmental Science & Technology

基　　金：国家自然科学基金(22176110,21972073,22136003);湖北省引智项目(2019BJH004);111引智项目(D20015)。

摘　　要：为进一步提高BiOBr对头孢菌素类抗生素的光催化降解能力,作者采用水热法合成了不同锰含量(5%、10%及30%)掺杂的BiOBr光催化剂(Mn/BiOBr)。通过扫描电子显微镜、X射线衍射光谱及X射线光电子能谱等表征,发现掺杂锰离子后BiOBr仍为片状结构,但其尺寸有所减小,锰离子以正二价形式(Mn^(2+))存在于纳米BiOBr晶格中。以抗生素头孢唑林(cefazolin sodium,CFZ)为污染物对象,在可见光照射下(λ≥420 nm),探讨了Mn/BiOBr光催化降解CFZ的特性,其中锰掺杂量为5%时(标记为Mn/BiOBr-5)对BiOBr的光催化活性提升最大。Mn/BiOBr-5对CFZ氧化降解的表观速率常数(k=0.02078 min^(–1))比BiOBr(k=0.00953 min^(–1))高118%,在140 min内降解98%的CFZ,而相同条件下70%的CFZ被BiOBr降解。与未掺杂BiOBr相比,掺入Mn^(2+)导致其比表面积增大及带隙能量降低,并使得光生电荷复合率降低,因而提升了BiOBr的光催化活性。此外,测定了反应体系氧化物种,结果表明羟基自由基及空穴为Mn/BiOBr降解CFZ反应过程中的主要活性物种。In order to improve the photodegradation efficiency of BiOBr towards cephalosporin antibiotics removal,BiOBr photocatalysts with different Mn-doping contents(5%,10%and 30%)(Mn/BiOBr)were synthesized by hydrothermal method.Through characterization by scanning electron microscopy,X-ray diffraction and X-ray photoelectron spectroscopy,it was found that BiOBr catalysts still possessed sheet-like structure after doping manganese but with reduced crystal size.And the doped manganese ions existed in the form of positive divalent(Mn^(2+))in the lattice of nano-BiOBr.The photocatalytic performance of Mn/BiOBr catalysts was investigated by taking the cefazolin sodium(CFZ)as the model pollutant under visible light irradiation(λ≥420 nm).The results showed that when the doping amount of Mn was 5%(labeled as Mn/BiOBr-5),the photocatalytic activity of BiOBr was improved the most.The apparent rate constant(k=0.02078 min^(–1))of Mn/BiOBr-5 for the oxidative degradation of CFZ was 118%higher than that of undoped BiOBr(k=0.00953 min^(–1),approximately 98%of CFZ removed within 140 min.However,only 70%of CFZ was degraded by pure BiOBr under the same conditions.Compared to undoped BiOBr,the doping of Mn^(2+)in BiOBr increased the specific surface area,and reduced both the band gap energy and the recombination rate of photogenerated charges,thus improving the photocatalytic activity of BiOBr.In addition,the oxidation species in the reaction system were determined,in which the hydroxyl radicals and holes mainly contributed to CFZ photodegradation by Mn/BiOBr.

关 键 词：MN掺杂 BiOBr 头孢唑林钠 光催化降解 机理 

分 类 号：X703[环境科学与工程—环境工程]