可见光协同钴铈铁氧体高效活化过一硫酸盐降解噻虫胺

本实验采用溶胶-凝胶燃烧的方法，将Co掺入到CeFeO3（CFO）钙钛矿晶格中制备了具有晶格缺陷的CeFe0.8Co0.2O3（CFCO）纳米颗粒催化剂。通过扫描电镜（SEM）、透射电镜（TEM）、X射线衍射（XRD）、Ｘ射线光电子能谱（XPS）等表征技术对CFCO催化剂进行表征分析，结果表明在CFCO上形成了表面氧空位（VO）。同时，还研究了过硫酸氢钾（PMS）用量、不同pH值对CFCO降解噻虫胺（CTD）的影响。结果表明，在CFCO投加量为0.6 g?L-1，PMS用量为0.8 mmol?L-1，pH为7时，20 mg?L-1的噻虫胺在30分钟内完全降解。并且经过4次循环使用后，噻虫胺降解率仍能达到91.2%。CFCO对于PMS的高效活化能力，主要归功于晶格缺陷所产生的电位差促使自由电子顺着氧空位快速定向传导到PMS上。为了模拟在天然水体环境中CFCO光催化活化PMS去除CTD，进行阴离子和有机酸的对比实验，分析了不同环境因素对CFCO降解噻虫胺的影响；此外，本文通过自由基淬灭实验与电子自旋共振（ESR）检测确定了CFCO光催化活化PMS降解噻虫胺实验中起主要作用的活性物种为单线态氧（1O2）与羟基自由基（?OH），并分析推测了自由基的产生机理。最后采用高效液相色谱-质谱联用仪（LC-MS）检测分析了CTD降解过程中可能产生的代谢产物，并基于代谢产物的产生顺序归纳出了三条可能的降解路径。

Visible light combined with cobalt-cerium ferrite to activate persulfate for clothianidin degradation

In this paper, through sol-gel combustion method, CeFe0.8Co0.2O3(CFCO) nano-particle catalyst was prepared by incorporated Co into CeFeO3(CFO) perovskite lattice. The catalyst was characterized by XPS, XRD, SEM, TEM and other characterization techniques and the result shows that surface oxygen vacancies (VO) were formed on CFCO. It was also investigated the effects of potassium peroxymonosulfate dosage and pH on the degradation of CTD by CFCO. The use of 0.6g?L-1 CFCO and 0.8mmol?L-1 PMS led to complete degradation of 20mg?L-1 clothianidin (CTD) in pH=7 within 30min. And the degradation rate of clothianidin still reached 91.2% after four times of recycling. the highly efficient activation of CFCO for PMS was mainly attributed to the potential difference created by the lattice defects driving the rapid directional conduction of free electrons down the oxygen vacancies to the PMS. Meanwhile, in order to simulate the removal of CTD by CFCO photocatalytic activation of PMS in natural water environment. We perform comparative experiments with anionic and organic acids. The influence of different environmental factors on the degradation of clothianidin by catalyst was analyzed. In addition, through radical quenching experiment and ESR detection, it was determined that the active oxygen free radicals that played the main role in the experiment of degrading clothianidin by photocatalytic activation of PMS were 1O2 and ?OH, and the mechanism of free radicals generation was analyzed and speculated. The possible metabolites in the degradation of CTD were analyzed by high performance liquid chromatography-mass spectrometry (LC-MS), and three degradation paths were summarized.