Study On The Removal Of Micropollutants By Photoelectric Assisted Flow-through Fenton-like System

Recently,environmental contamination and ecotoxicity caused by micropollutants in water have aroused widespread concern all over the world.Among them,antibiotics are common micropollutants in water,which were not effectively removed by traditional water remediation strategies,so it is urgent to explore tailored treatment technologies.Based on this,a flow-through photo/electric activated Fenton-like system was designed and developed based on modified carbon nanotube composite membrane.Firstly,MIL-101（Fe）-modified carbon nanotube composite membrane（O-CNT@MIL-101（Fe））were prepared by solvent thermal-vacuum filtration process,tetracycline was selected as the target contaminant.The structure-effect relationship between the preparation conditions and composite membrane physicochemical properties was clarified with advanced characterization techniques,and illustrates the working mechanism of the flow-through system.The details of the study are as follows:（1）A flow-through electro-Fenton system based on O-CNT@MIL-101（Fe）composite membrane.The results showed that the operating parameters such as dissolved oxygen value and applied voltage had significant effects on tetracycline degradation kinetics.Tetracycline was removed and mineralized at 93.2% and 69.0%,respectively,within a reaction time of 2 h.The mass spectrometry measurements indicated that tetracycline molecule oxidation process includes hydroxylation oxidation,ring opening and group removal.In addition,the cycling experiments and tetracycline degradation experiments under different background matrices showed that the proposed nanocomposite membrane has excellent regeneration ability and chemical stability.（2）A flow-through Fenton-like system based on O-CNT@MIL-101（Fe）composite membrane.Due to the excellent photoelectrochemical response performance of the composite membrane,a photoelectron activated peroxymonosulfate（PMS）filtration system was also designed and explored.The differences in the tetracycline degradation performance of the electroactivated PMS system,photoactivated PMS system and photoelectric co-activated PMS system were compared and analyzed.The results revealed that the composite membrane exhibited a remarkable photoelectric synergism.Under the combined effect of light and-2 V electric field,100% tetracycline removal and 51.7% total organic carbon removal could be achieved within 20 min.It is attributed to the fact that MIL-101（Fe）has a favorable UV light responsiveness and a large number of unsaturated iron active sites.The application of electric field also contributes to the effective separation of the photogenerated electron/hole pairs generated within the system.Electron paramagnetic resonance techniques and quenching experiments demonstrated that both sulfate/hydroxyl radicals and singlet oxygen contributed jointly to the tetracycline removal.Low concentrations of chloride and nitrate ions had no significant influence on the system,and only carbonate ions had a slight inhibitory effect.Moreover,the technology showed excellent removal of other novel organic pollutants（methylene blue,congo red and p-nitrophenol）.The proposed two systems in this study could provide an efficient,economical and environmentally friendly method for remediating antibiotic pollution in water bodies.