摘要
通过水热法制备了Ti(Ⅳ)掺杂Bi2O3(BTO),采用扫描电镜(SEM)、X射线粉末衍射(XRD)、X射线光电子能谱(XPS)等技术对其形貌和结构进行表征,并考察了钛掺杂氧化铋光催化降解水中PFOA的降解效果,发现PFOA的降解符合一级反应动力学,其降解速率常数为-0.2 h-1,比商业用纳米二氧化钛P25提高了6.8倍.表征结果证明,BTO存在多孔结构,能够增加反应活性位点,提高光催化活性面积.同时,自由基捕获实验和中间产物分析表明,光生空穴对PFOA的断链分解起决定性作用;同时Bi—O—Ti表面基团吸附PFOA并弱化了C—F键,导致光生电子可自由移至C—F键上并实现还原脱氟;光生电子和空穴在功能上相互配合,实现了对PFOA的协同降解;PFOA的降解过程受还原性物质主导,通过C—C键的断裂生成短链全氟羧酸类物质.
Ti(Ⅳ)doped Bi2O3(BTO)was synthesized by hydrothermal method,The morphological and structural characterizations were conducted by using scanning electron microscopy(SEM),X-ray powder diffraction(XRD),X-ray photoelectron spectroscopy(XPS).The photocatalytic degradation of perfluorooctanoic acid(PFOA)by BTO was also investigated.The results showed that the degradation of PFOA conforms to pseudo-first-order kinetics,and the degradation rate constant of PFOA by BTO was-0.2 h-1,6.8 times as high as that by nano TiO2(commercial P25).The porous structure in the BTO was ascribed to the abundant active sites and enhanced photocatalytic activity.Free radical experiments and analysis of intermediate products showed that photo-generated holes played a key role in chain breaking of PFOA.Meanwhile,the surface functional groups of Bi—O—Ti adsorbed PFOA and weakened the C—F bond,leading to the transfer of electrons to the C—F bond and then defluorination reductively.Photogenerated electrons and holes cooperated functionally to degradation of PFOA,the process of which was evidenced to be dominated by reducing substances,and underwent the break of the C—C bonds to give the short chain perfluorocarboxylic acids.
作者
李惠惠
张圆正
嵇阳远
王凯旋
殷立峰
LI Huihui;ZHANG Yuanzheng;JI Yangyuan;WANG Kaixuan;YIN Lifeng(Beijing Normal University,School of Environment,State Key Laboratory of Environmental Simulation and Pollution Control,Beijing,100875,China)
出处
《环境化学》
CAS
CSCD
北大核心
2020年第5期1202-1209,共8页
Environmental Chemistry
基金
国家自然科学基金(21777009)
北京市自然科学基金(8182031)资助
关键词
光催化
降解
全氟辛基羧酸
钛掺杂氧化铋
photocatalysis
degradation
perfluorooctanoic acid
Ti(Ⅳ)doped Bi2O3
作者简介
通讯联系人:殷立峰,Tel:18911569487,E-mail:lfyin@bnu.edu.cn
