Synthesis Of Iron-Manganese-Based Composite Electrode Materials And Their Photo/Electro Synergistic Fenton Degradation Performance Of Tetracycline

With the widespread use of tetracycline antibiotics,drug residues have posed a great threat to the ecological environment and human health.To solve the problem of low Fe²⁺regeneration efficiency and low degradation efficiency of non-homogeneous Fenton in advanced oxidation technology,the photo/electro assisted Fenton system was constructed by using narrow band gap manganese ferrite（MnFe₂O₄）as the basic catalytic material.In order to overcome the shortcomings of low photoelectric conversion performance and poor regeneration rate of Mn²⁺and Fe²⁺in the basic material of MnFe₂O₄.By using two-dimensional layered nanomaterial molybdenum disulfide（MoS₂）as the modified component,the electron transfer ability of composite electrode material was enhanced,and the transformation of Mn³⁺/Mn²⁺and Fe³⁺/Fe²⁺was accelerated,which effectively improved the original defects of MnFe₂O₄.The research results of this paper provided theoretical basis and technical support for the purification of refractory organic matter by photo/electro assisted Fenton technology based on MoS₂/MnFe₂O₄ composite material.The specific research results of this paper were as follows:（1）The electrocatalytic electrode material manganese ferrite@carbon felt（MnFe₂O₄@CF）was prepared by solvothermal synthesis.The structure,composition,light absorption and electrochemical properties of the electrode materials were analyzed.MnFe₂O₄@CF electrode material had a network fiber structure of carbon felt,and spherical MnFe₂O₄ particles grew uniformly on the surface of carbon felt fiber.MnFe₂O₄@CF electrode had good electrode activity and conductivity.The MnFe₂O₄@CF electrode was used as the cathode in the heterogeneous photo/electro assisted Fenton system.The optimal conditions for tetracycline degradation of the heterogeneous photo/electro assisted Fenton system were obtained by analyzing and optimizing the influencing factors such as initial tetracycline concentration,initial p H,applied current and electrode spacing.Under the conditions of initial tetracycline concentration of 25mg/L,initial p H=3,external current of 200m A and electrode spacing of 1.5cm,the removal rate of tetracycline in the solution was 91.23%after120min.After 5 cycles of experiments,the degradation rate of tetracycline was 85.51%,indicating good cycle stability.·OH played a leading role in the process of radical quenching and the possible mechanism was proposed.（2）In order to improve the limitation of MnFe₂O₄ in heterogeneous photo/electro assisted Fenton system,MoS₂/MnFe₂O₄@CF electrode was successfully prepared by loading MoS₂ on MnFe₂O₄@CF electrode surface by hydrothermal method based on MnFe₂O₄@CF.MnFe₂O₄ particles with octahedral cube structure were uniformly grown on the surface of carbon felt fiber,and MoS₂ nanoflowers were uniformly grown on the surface of MnFe₂O₄@CF electrode with layered structure.The MoS₂/MnFe₂O₄@CF electrode had a wider range of visible light absorption due to the load of MoS₂,and a narrower band gap width,which can better inhibit the photoinduced electron and hole recombination.MoS₂/MnFe₂O₄@CF electrode had good electrical conductivity and reactivity.MoS₂/MnFe₂O₄@CF electrode was applied to degrade tetracycline in heterogeneous photo/electro assisted Fenton system.Under the conditions of initial tetracycline concentration of 25mg/L,initial p H=3,applied current of 200m A and electrode spacing of 1.5cm,the removal rate of tetracycline in solution was 95.65%after 120min.The degradation rate of tetracycline in solution was further improved.This is because the introduction of MoS₂ increased the lifetime of photoinduced electrons and holes,which can increase the production of·OH and·O₂^-.The presence of Mo⁴⁺/Mo⁶⁺can increase the generation of·OH,and also enhance the regeneration of Fe²⁺and Mn²⁺.After 5 cycles of experiments,the degradation rate of tetracycline was 87.96%,showing good cycle stability.The results of radical quenching experiments showed that·OH and electron play important roles in the reaction process and the possible mechanism was proposed.