Preparation Of BDD And Ti/SnO₂ Modified Electrode And Its Electrooxidative Degradation Of F-53B

2-[?6-chloro-1,1,2,2,3,3,4,4,5,5,6,6-dodecafluorohexyl?oxy]-1,1,2,2-tetraPotassium fluoroethanesulfonate?F-53B?is a chromium mist inhibitor in the electroplating chromium industry.Like other perfluorinated compounds,it has environmental stability hard-to-degrade properties and biological toxicity.There are few studies on the degradation of F-53B at home and abroad.There are mainly ball milling,resin adsorption,oxidant oxidation.etc.However,these methods have disadvantages of long degradation time,high energy consumption or high cost,and low defluorination ratios.Electro-oxidationtechnologies are a hotspot in recent environmental chemistry research.They have advantages of high efficiency,simple operation device,and high oxidation removal ratios.Electro-oxidation technology technologies were used to deal with persistent organic pollutants.In this study,boron-doped diamond?BDD?was prepared by plasma chemical deposition,and BDD/SnO₂,BDD/PbO₂,and BDD/SnO₂-F were prepared by homogenous co-deposition on the basis of BDD electrode..Scanning electron microscopy?SEM?,energy dispersive spectroscopy?EDS?and X-ray diffraction?XRD?were used to characterize the surface morphology,doping elements and grain size of the electrode.Electrochemical performance of the electrode was characterized by alternating current impedance?IMP?,electrode accelerated life test,linear sweep voltammetry?LSV?and electrode contact angle.Through comprehensive comparison and analysis of the surface and surface properties and electrochemical performance of the four electrodes,the screening of high-efficiency BDD/SnO₂-F electrodes for the electro-oxidation of F-53B was studied.Then the conditions of electrooxidative degradation of F-53B at BDD/SnO₂-F electrode were optimized and the mechanism of degradation was analyzed.The effects of electrode material,element doping ratio,calcining temperature,current density,electrolyte,initial pH of the solution,initial concentration,degradation voltage,electrolyte concentration,electrode plate spacing on the degradation ratios of F-53B and defluorination rate were investigated.Under the experimental conditions of BDD/SnO₂-F as the anode,the Sn:F doping ratio of1:2,the calcining temperature of 450?.,the current density of 30 mA/cm²,the initial pH of3,1.0 mol/LNaCl,the initial concentration of 100 mg/L,the degradation voltage of 6 V,and the distance between the plates of 0.5 cm.after 30 min electrolysis,the degradation ratios of F-53 was as high as 95.6%.The intermediates formed during the degradation of F-53B were analyzed by HPLC-MS/MS,and the degradation mechanism of F-53B electrooxidation was analyzed.High-efficiency Ti/SnO₂-Sb-PVDF electrodes were prepared by electrodeposition using PVDF modification.The surface morphology,element doping and atomic specific gravity of the electrodes were analyzed by SEM and ENS.It was found that the surface of Ti/SnO2-Sb-PVDF electrodes were fine and uniform doping,and the surface of titanium substrate was completely covered by a dense electrodeposited oxide layer.Electrode properties such as oxygen evolution potential,AC impedance,electrode life,and contact angle were characterized.The results show that the oxygen evolution potential obtained after PVDF modification is increased by 0.4V and the electrode life is increased from 2.79h to 51h.The life service of the electrode is greatly prolonged.The degradation and the kinetics analysis of F-53B at Ti/SnO₂,Ti/SnO₂-Sb and Ti/SnO₂-Sb-PVDF electrodes were discussed in detail.It was found that the degradation efficiency of F-53B at Ti/SnO₂-Sb-PVDF was the highest,reaching 89.62%.The effects of the current density,initial pH value,electrolyte,initial concentration,H₂O₂,andO₃ on the degradation ratios of F-53B were investigated using Ti/SnO₂-Sb-PVDF electrode.Under the experimental conditions of current density of25mA/cm2,the initial pH of 3,1M NaClO₄ and the initial concentration of 100mg/L,the degradation rate of F-53B was the highest.Through the tangent method,the initial oxidation potential of F-53B is determined to be 3.8V.