Preparation Of Modified Ti/SnO₂-Sb Electrode And Degradation Of Antibiotics In Water

In recent years,antibiotic contamination in aquatic environments has been severe.The widespread abuse of antibiotics has led to an increase in the amount of antibiotics in aquatic environments,and antibiotics as persistent new pollutants?PPCPs?have been found in various organisms and humans in the environment.Potential hazards.The vast majority of antibiotics,due to their antibacterial properties,cannot be digested in the human body system and persist for a long time and continue to accumulate.The traditional method of domestic sludge can not effectively remove the antibiotics,so the search for an effective antibiotic wastewater treatment method is the current research hotspot.Electrochemical oxidation technology is at the forefront of the current environmental engineering field.It can quickly and efficiently generate hydroxyl radicals to degrade organic substances in water during the reaction process.Electrodes,for biodegradable organics such as antibiotics,they also have better degradation efficiency,as the core of electrocatalytic oxidation technology,play a key role in the water treatment process.Therefore,the research of electrocatalytic electrode with high catalytic activity and long life is the focus of this research.In this experiment,different transition metal-doped Ti/SnO₂-Sb electrodes were prepared by sol-gel heat treatment.The main research contents include:?1?Based on the preparation of Ti/SnO₂-Sb electrode,a variety of transition metal doping was performed.Hetero-modification studies were conducted to characterize the effect of transition metal element doping on the performance of the electrode by morphing the electrode surface,composition and distribution of coating chemical elements,coating structure,electrode life testing,and electrocatalytic degradation of norfloxacin.In order to screen out the best electrode.?2?The degradation mechanism of electrocatalytic oxidation of norfloxacin by modified electrode was preliminarily analyzed by cyclic voltammetry,linear voltammetry and ultraviolet-visible spectroscopy.?3?Degradation of norfloxacin simulated wastewater with the best electrode after screening as an anode,to explore the influencing factors of electrocatalytic oxidation process,and to determine the best conditions.Experimental studies have reached the following conclusions:?1?Transition metal-doped Ti/SnO₂-Sb-Ni,Ti/SnO₂-Sb-Mo electrodes were prepared by sol-gel method.The doped elements did not affect the tetragonal rutile structure of SnO₂itself.The crack on the surface of the the electrode doped with Ni coating is reduced,forming smaller crystal grains and distributing evenly;the surface of the electrode doped with Mo appears agglomeration,and the concavity and convexity are reduced and the surface is flatter.XRD results showed that the doping of transition metal elements formed a high-index primary crystal surface of SnO₂ crystal,but no doping of the transition metal was detected,probably due to the low content of doping elements or enter the lattice by substitution or caulking,and EDS spectrum analysis of the presence of transition metals also confirmed this point.Ni and Mo doping can increase the electrocatalytic activity of the electrode surface,and Ni doping has the best removal effect of norfloxacin.?2?The results of electrochemical analysis show that Ni and Mo doping can increase the oxygen evolution potential of the electrode itself,but the Ni-doped electrode has a higher oxygen evolution potential.In the process of degradation of norfloxacin,Mo-doped electrode reactions are mainly direct electrochemical reactions.Ni doping electrodes mainly undergo indirect electrochemical reactions and generate a large amount of·OH,thereby eliminating norfloxacin.In the process of degradation of norfloxacin,various types of intermediate products are produced,and the intermediate product and the target pollutant have competition relationship,so that the more the reaction proceeds,the lower the degradation rate is.?3?Set the preparated Ti/SnO₂-Sb-Ni electrode as electrocatalytic anode,the effective area of the electrode plate is 40cm²,the distance between adjacent electrodes is 20mm,the current density is 20mA/cm²,the pH value is 3,The initial concentration of Norfloxacin was100mg/L,and Na₂SO₄ concentration was 0.25mol/L.After 30 min of reaction,the removal rate of norfloxacin reached 100%,and after 120 min of reaction the TOC removal rate reached75%.