Degradation Of Bisphenol A With PMS Actived By Photocatalysis And Photoelectrocatalysis

Bisphenol A（BPA）,a represented endocrine disrupting chemicals,has been regarded as a emerging micropollutant because of its low concentration,high toxicity and degradation-resistant.It can be hardly removed by the traditional water treatment technology,resulting in a large amount of residue and accumulation of BPA in the environment,and it is a potential threat to the health of humans and animals.In this work,three new photocatalysis（PC）or photoelectrocatalysis（PEC）systems have been prepared by the combination of PC or PEC and sulfate radical(SO₄^·-)-based advanced oxidation technology（SR-AOP）.The catalytic performances of these systems have been evaluated toward BPA degradation in the presence of PMS under visible light irradiation.The main contents of this work have been done and shown as follows:（1）A novel MnFe₂O₄/g-C₃N₄ composite photocatalyst was prepared through a facile hydrothermal method and its photocatalytic activity for BPA degradation was evaluated.Compared with bare g-C₃N₄,the MnFe₂O₄/g-C₃N₄ composite exhibited improved photocatalytic activity for BPA degradation in the presence of PMS under visible light irradiation.Almost 98%of BPA can be degraded after 2 h irradiation by the 20%MnFe₂O₄/g-C₃N₄ with dosage of 0.5g·L^-1 under the optimal condition of 1 mmol·L^-1 PMS.Photoelectrochemical data further confirmed the enhanced charge carrier separation performance of composite.The radical trapping experiments revealed that the SO₄^·-,·O^2-and h+shown responsible for BPA degradation in the photocatalytic process.Moreover,repeating experiments showed that MnFe₂O₄/g-C₃N₄composite possessed robust stability.（2）In order to solve the problems of metal dissolution and recovery,a novel Bi VO₄-MnFe₂O₄@CFP photoelectrocatalysis system was constructed by employing Bi VO₄ as photoanode and MnFe₂O₄ modified carbon fiber paper（MnFe₂O₄@CFP）as cathode.The PEC performances of BPA degradation over Bi VO₄-MnFe₂O₄@CFP system in the presence of PMS were investigated.Nearly 100%of BPA can be degraded after 1.5 h irradiation under the optimal condition of 1.0 V applied bias and 1 mmol·L^-1 PMS.Radical trapping experiments and electron spin resonance（ESR）confirmed that the generated·OH and SO₄^·-showed the responsible for BPA degradation during PEC reaction.The results of XPS indicated the favorable redox reaction between MnFe₂O₄@CFP and PMS,which results in the generation of high active SO₄^·-.More importantly,the PEC process can accelerate the PMS activation of MnFe₂O₄ to produce abundant oxidative radical species for efficient BPA degradation.（3）In order to solve the problem of incomplete recovery of metal,a novel Bi VO₄/B-CAs photoelectrocatalysis system was prepared by using Bi VO₄ as photoanode and Boron doped carbon aerogels（B-CAs）as cathode.Upon PMS concentration and applied bias,the degradation rate of BPA was first accelerated and then decreased.Almost 100%of BPA can be degraded after3 hours irradiation under the optimal condition of 10 mmol·L^-1 B-doping,0.75 V applied bias and0.75 mmol·L^-1 PMS.Radical trapping experiments and electron spin resonance（ESR）indicated that the generated·OH,¹O₂ and·O₂^-showed the contribution for BPA degradation,which the¹O₂ and·O₂^-were the main active species.The results of cycling test suggested the excellent stablity of the system.Moreover,the system exhibited superior photoelectrocatalytic performance for the BPA,2,4-DCP and Ph OH degradation in the presence of PMS,which further confirmed the excellent catalytic activity of Bi VO₄/B-CAs/PEC system for efficient pollutants degradation.In this study,a variety of advanced oxidation process were coupled to realize the efficient degradation of BPA by utilizing the strong active free radicals generated in the reaction process.In addition,electrocatalysis and non-metallic materials were introduced to realize the gradual greening of the degradation,which provided the research foundation for the application of the high-efficiency catalytic system in the field of water pollution control in the future.