Preparation Of Red Mud Based Particle Electrode And The Study Of Catalytic Degradation Of Ciprofloxacin By Particle Electrode In Three-dimensional Electrochemical System

In recent years,with the increasing demand for antibiotics in China,antibiotics had been widespread overused and misused.Antibiotics had been detected in drinking water,groundwater,surface water and various kinds of wastewater in China,and their concentrations in the environment were approaching dangerous levels.Ciprofloxacin（CIP）is one of the most widely used antibiotics that can enter the human body through the food chain and cause damage to the heart and nervous system.Therefore,it is very necessary to explore the effective removal method of CIP.The traditional treatment methods to treat CIP had the disadvantages such as long treatment time,low degradation efficiency and high cost.Three-dimensional electrochemical water treatment technology,as a novel type of advanced oxidation technology,had extensive attention for degrading antibiotics successfully because of its high efficiency,easy operation,and environmental friendliness.Therefore,it has practical application significance to explore three-dimensional electrochemical technology to degrade CIP.In this study,red mud and copper nitrate as raw materials to prepare a series of copper oxide doped red mud particle electrode and copper ferrite based on red mud particle electrode,and respectively applied in three-dimensional electrode/electro-Fenton system（3D/EF）and three-dimensional electrode/photoelectric-persulfate（Vis-3D/E+PS）system for CIP degradation.The performance of the two particle electrodes for the removal of CIP in 3D/EF system and Vis-3D/E+PS system were evaluated.The influence of preparation conditions on the performance of particle electrode,the catalytic mechanism of particle electrode catalyzed three-dimensional electrochemical system,the influence of different operation conditions on the degradation of CIP in three-dimensional electrochemical system catalyzed by particle electrode,and energy consumption calculation of two-dimensional and three-dimensional electrochemical system were evaluated.The specific research contents and results are as follows:Red mud based Cu O（Cu O/URM）particle electrodes with different Cu O doping contents were prepared by physical impregnation method with ultrasonic assistance,and applied in 3D/EF system for CIP degradation.By investigating the preparation conditions of the particle electrode,the optimal preparation conditions of the particle electrode were determined as follows:the doped metal oxide was Cu O,the impregnation concentration was 0.1 mol/L,the calcination temperature was 300 ^oC,the calcination time was 8 h and the ultrasonic impregnation time was20 min.The synthesized Cu O/URM particle electrode were characterized by FE-SEM,EDS,TEM,HRTEM,XRD,BET,XPS and EIS.The results show that the prepared Cu O/URM particle electrode had excellent mesopore structure and high specific surface area,and the doping of Cu O could effectively reduce the resistance of particle electrode and accelerate the electron transfer.Based on XPS analysis,active species capture experiment and ESR data,it was found that·OH and·O₂^-were the main active species in Cu O/URM-catalyzed 3D/EF system.In addition,the process optimization results show that the degradation efficiency of CIP was 80.66%under the optimal reaction conditions after 80 min,the degradation efficiency of CIP reached 76.84%at the initial p H of 9,indicating that the Cu O/URM electrodes had great potential for practical application under neutral and even alkaline conditions.it was found that Cl^-promoted the degradation of CIP,while the NO₃^-,HCO₃^-,and H₂PO₄^-had an inhibitory effect on CIP degradation.In addition,compared with 2D/E system,3D/EF system had more excellent removal capability of CIP and higher power energy utilization efficiency.Copper ferrite on based red mud（Cu Fe₂O₄/RM）particle electrode was prepared by solid phase method and applied in Vis-3D/E+PS system for CIP degradation.The optimum preparation conditions of Cu Fe₂O₄/RM particle electrode were determined as follows:Mass ratio of Cu（NO₃）₂·3H₂O to RM was0.5:1,calcination temperature was 800 ^oC,calcination time was 2 h.Under the optimal operating conditions of Cu Fe₂O₄/RM dosage of 1 g/L,PS dosage of 9mmol/L,initial p H of 7 and applied voltage of 17 V,the degradation efficiency of CIP reached 71.39%at 60 min.The analysis results of active species capture experiments proved that h⁺,SO4^·-and·O₂^-were the main active species.Based on the XPS analysis,capture of active species experiment,the possible catalytic mechanism for electrocatalytic degradation of CIP catalyzed by Cu Fe₂O₄/RM particle electrode was proposed.In addition,the recycling results show that the degradation efficiency of CIP almost was not decreased significantly after three runs,and the characteristic peaks of XPS of Cu Fe₂O₄/RM hardly changed after four recycles,confirming that Cu Fe₂O₄/RM had good electrochemical performance and stability.