Research On Performance And Mechanism Of MAGNéLI-PHASE Ti₄O₇ Reactive Electrochemical Membrane For Electrochemical Disinfection

The global epidemic of COVID-19 has aroused widespread attention to water disinfection and sterilization technology.Electric disinfection technology is widely regarded as the"next generation water disinfection technology"because of its excellent performance.The selection of electrode materials and the design of reactor configuration are two key problems in the development of electric disinfection technology.The titanium oxide material unique crystal structure to ensure that it has good electrical conductivity,stability and electrochemical activity,therefore this research adopts the titanium oxide as anode,and the designed active electrochemical membrane,using Escherichia coli as model organisms,study the titanium oxide film electrode on the effectiveness and mechanism of inactivated bacteria,so as to provide support and guidance for practical application.In this paper,the material characterization and performance test of titanium oxide film electrode were carried out.The prepared materials are mainly macroporous and mesoporous,the main elements are Ti and O,and the crystal phase is dominated by Ti₄O₇.Electrochemical impedance spectroscopy（EIS）and Tafel curve test show that titanium oxide has good electrical conductivity,and its internal resistance of charge transfer and diffusion is low.The cyclic voltammetry curve shows that the titanium oxide can remain stable during the electrolysis process.At the same time,its electrochemical active area is nearly 300 times that of geometric area.The horizontal convection process of pathogen diffusion to the electrode surface was improved by enhanced mass transfer with a mass transfer rate constant of 3.95×10^-5ms^-1.The influence of different influencing factors on membrane electrode electrochemical sterilization was explored.The current density was 10mAcm^-2,the membrane flux was0.04mLcm^-2s^-1,and the initial bacterial concentration was 10⁷CFU mL^-1.After 45minutes of reaction,the pathogen was completely inactivated（>7.1log）.In addition,the titanium oxide film electrode has good resistance to impact load capacity,enhance current density can reinforce the oxidation process,the improvement of membrane flux can strengthen the mass transfer process of pathogens to the electrode surface,when there is a certain concentration of chloride ion,membrane electrode can be generated by active chlorine way to improve the effect of inactivated bacteria.The negatively charged pathogens arrive at the surface of anode under the action of electric adsorption and film interception,and are subsequently inactivated under the action of electrochemical oxidation,in which direct oxidation plays a major role.Under the action of electrooxidation,cell wall and cell membrane are first attacked,folds and holes appear,intracellular proteins,nucleic acids and K⁺leakage,the structural and functional integrity of cell membrane are destroyed,bacterial proteins and leaking DNA continue to mineralize and decompose in the process of electrooxidation.In addition,under the attack of ROS produced by indirect oxidation,cells will undergo lipid peroxidation,and the resulting lipid peroxidation product malondialdehyde will cause damage to key enzymes in mitochondria.The above studies show that the MAGNéLI-PHASE Ti₄O₇ reactive electrochemical membrane not only has good electrochemical and mass transfer performance,but also can realize the rapid and efficient inactivation of pathogens.The study on the electrochemical sterilization performance and mechanism of the titanium oxide film electrode provides a theoretical basis for the practical application and has a certain guiding significance.