Photoelectrochemical Activity Of Cupric Ion Doped TiO₂ Film For Photoelectrocatalytic Degradation Of Ofloxacin

With the widespread use of antibiotics,pollution of antibiotic has became a major environmental problem.More and more rivers and lakes have detected the presence of antibiotics.Because the wastewater treatment technologies are difficult to remove antibiotics effectively,resulting in a large number of medical wastewater and agricultural wastewater containing antibiotics are discharged into the natural water body,which poses a serious threat to the ecosystem and human health,so it is important to study the degradation methods of wastewater containing antibiotics.As an advanced oxidation technology,photocatalysis has strong oxidation performance and can remove organic pollutants effectively.In this paper,photocatalysis technology is used to degrade simulated wastewater containing antibiotics.In this paper,firstly,the photocatalysis electrode was prepared,and the Cu2+doped TiO2 nanotube electrode was prepared by the combination of the anodic oxidation method and the immersion deposition method with HF as the electrolyte.The photoelectric properties of the electrode were characterized by electrochemical workstation and infrared spectrometer.The characteristic absorption peaks of O-Ti-O bond and Cu2+in the electrode were prepared by infrared spectrometer,which indicated that TiO2 thin film was successfully formed on titanium plate substrate and Cu2+was successfully doped into TiO2 lattice.The photocurrent,impedance,Mott Schottky and cyclic voltammetric curves were used to characterize the photoresponse,electron mobility,interface electrochemistry and electrode stability of Cu2+/TiO2 electrode.The results showed that the prepared electrode had better photoresponse performance,smaller interface resistance,better electron mobility and better stability,which could be reused many times.Then,the simulated wastewater containing ofloxacin was treated by the photocatalysis of Cu2+/TiO2 electrode prepared by the above method.The catalytic capacity and kinetic characteristics of the photocatalysis degradation with Cu2+/TiO2 as the electrode were explored,and the effects of voltage,pH,Na2SO4 electrolyte concentration,initial concentration,light intensity and dissolved oxygen on the photocatalysis efficiency were analyzed The degradation conditions were optimized.The experimental results show that the degradation efficiency and reaction rate of photocatalysis are higher than that of semiconductor photocatalysis and electrocatalysis,showing a good photoelectric synergistic effect;the kinetic characteristics of Cu2+/TiO2 photocatalytic degradation of ofloxacin conform to the Langmuir Hinshelwood kinetic model;in a certain voltage range,the photocatalytic performance And the degradation efficiency of pollutants increases with the increase of voltage,the optimal voltage condition is 2V;acid or alkaline environment conditions will inhibit the efficiency of photocatalysis,the optimal pH value is 7;adding a certain concentration of Na2SO4 electrolyte solution can improve the conductivity of wastewater,which is conducive to the transfer of electrons and thus improve the efficiency of photocatalysis,but high concentration of Na2SO4 will lead to side reactions Therefore,the optimal concentration of electrolyte solution is 0.1mol/L.In a certain range,the increase of the initial concentration of ofloxacin waste liquid is conducive to the reaction,but due to the limited surface area of the electrode,the initial concentration cannot be too high.5mmol/L is the most appropriate under experimental conditions.The increase of light intensity and dissolved oxygen can improve the photocatalysis of pollutants Degradation rate and reaction rate.Under the optimum conditions,the degradation rate of ofloxacin by Cu2+/TiO2 Electrode photocatalysis was 74.89%.In addition,the mineralization degree of ofloxacin simulated wastewater was studied.It was found that the mineralization degree and mineralization rate of the photocatalysis process to ofloxacin were significantly lower than the degradation rate and degradation rate of ofloxacin.The reason may be that only part of ofloxacin was completely degraded into inorganic small molecules such as CO2,H2O and NOx in the degradation process,and part of ofloxacin was degraded into a series of intermediate products without complete inorganic carbonization.Finally,the possible reactions and degradation approaches of photocatalysis in the degradation process of ofloxacin simulated wastewater are summarized.