Study On The Catalytic Oxidative Degradation Process Of Tetracycline Wastewater In Photoelectric Cooperative Fenton System By Fe₃O₄/Carbon Felt

Tetracycline wastewater is a typical difficult-to-treat antibiotic wastewater.Because of its toxicity to humans and the environment,its effective treatment has become a current research focus.The·OH produced by the Fenton treatment method has strong oxidizing properties and can remove most refractory organic pollutants including tetracycline.However,there are still some deficiencies in the use of traditional Fenton technology.In this paper,a heterogeneous solid catalyst was prepared by loading Fe₃O₄ onto carbon felt using hydrothermal method.The degradation performance of tetracycline in the electric Fenton and photoelectric Fenton systems was studied.The mechanism of action of the system and infer the degradation pathway of tetracycline.A variety of characterization methods were used to characterize the prepared catalyst materials to observe the composition,structure,morphology,electrochemical properties,etc.of the materials.Through research,it is found that the carbon felt material doped with ferric oxide not only retains the cubic structure of ferric oxide,but also the fiber structure of the carbon felt has not been significantly damaged.Therefore,it not only retains the adsorption performance of the carbon felt,but also increases the conductivity of the material.With tetracycline wastewater as the target pollutant,the catalytic performance and cycle stability of the prepared catalyst materials in the photoelectric Fenton system were studied.The results are as follows:In the electro-Fenton system,at a pH of approximately 3,an initial concentration of tetracycline of 50 mg/L,an initial current value of 0.2 A,an aeration flow rate of 300 mL/min,and an electrolyte concentration of 0.2 mol/L,Using the prepared catalyst to degrade tetracycline wastewater,the removal rate can reach 93.5%and the mineralization rate can reach 80.6%after 120min.After repeated use 5 times,the removal rate can still reach 86.3%.After adding the effect of light,the initial pH value is 7 and the light source is 10 W ultraviolet light.With the remaining conditions unchanged,the removal rate of tetracycline can reach99.1%and the mineralization rate can reach 88.2%after 120 min.In the electric Fenton and photoelectric Fenton systems,by observing the changes of various indicators during the degradation process,we can get the process of Fenton system degradation of tetracycline wastewater:In the process of electro-Fenton,Fenton reaction can generate·OH,OH^-and Fe³⁺.The conversion of Fe³⁺to Fe²⁺at the cathode can make Fenton reaction continue.·OH can degrade tetracycline and the acidic intermediate generated during the degradation The product,OH^-,interacts with acidic intermediates produced during the degradation of tetracycline to maintain the pH of the system.In the electric Fenton system with the addition of ultraviolet light,the degradation process is generally consistent,but the degradation rate is accelerated,and the reaction can occur in a wider pH range.This is due to the photodegradable aeration caused by ultraviolet light.H₂O₂ forms more·OH,which accelerates the degradation rate of tetracycline and the faster the production of acidic intermediates,so the pH value gradually decreases during the reaction under neutral conditions,which can promote the occurrence of Fenton reaction.Throughout the entire reaction process,through the determination of intermediate by-products,the degradation pathway of tetracycline can be inferred:the degradation of tetracycline will pass through two pathways,one is hydroxylation of·OH and the other is the removal of Methylation.Under these effects,reactions such as bond breaking,ring opening,and group destruction occur,and then through the action of free radical groups,they are further degraded and mineralized into small molecules such as oxalic acid,formic acid and other minerals,as well as CO₂ and H₂O mineralized products.