Study On Degradation Of Bisphenol A In Water By Copper-Manganese Composite Oxide Activated Peroxydisulfate

As a kind of organic pollutants with high detection and difficult degradation,bisphenol A has great toxic effect on organism and human body.In recent years,the utilization of advanced oxidation processes（AOPs）in chemical treatment methods has been extensively studied and applied,with the potential to effectively degrade organic pollutants.AOPs used catalyst to activate oxidants and produce highly oxidizing active species(such as·OH,SO₄^·-,¹O₂,O₂^·-)to attack organic pollutants,and decompose them into various small molecules or directly mineralize them into CO₂ and H₂O.In this paper,stable spinel-type and perovskite-type oxide catalysts were synthesized based on cheap and environmentally friendly transition metals of copper and manganese.Peroxydisulfate（PDS）was used as oxidant to construct a catalytic system,optimize the catalytic performance,and explore the degradation mechanism of pollutants in different catalytic systems.The specific research results are as follows:（1）Mn₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄（simple as MMCM）spinel catalyst was synthesized by citrate complexation method with Cu:Mn=1:9.The catalytic system composed of 0.2 g/L MMCM and 2 m M PDS could completely degrade BPA（10 mg/L）within 120 min.The leaching concentration of metal ions was low（Cu 0.54 mg/L,Mn 1.29 mg/L）,and TOC reached66.17%.When the catalysis was repeated for five cycles,BPA degradation still close to 100%,with high stability.The main active species in the system was O₂^·-.≡Mn（Ⅱ）and Vo^··were the main active sites on the catalyst surface.The synergistic effect of≡Cu（Ⅰ）/≡Cu（Ⅱ）and≡Mn（Ⅱ）/≡Mn（Ⅲ）oxidation-reduction pairs enables the catalytic degradation reaction to continue.The catalyst’s benefits are manifold:its high activity,chemical stability,and environmental friendliness make it ideal for removal of organic pollutants from aqueous system.（2）In order to further improve the degradation efficiency and mineralization degree of BPA,LaCu_0.5Mn_0.5O₃（simple as LCMO）perovskite was synthesized by the gel sol method.Compared with spinel,LCMO/PDS system could completely degrade BPA（10 mg/L）under the conditions of 0.12 g/L catalyst and 1.2 m M PDS,and the BPA mineralization reached74.91%,which was 8.74%higher than that of spinel.In the reaction process,the amount of ion leaching was less（Cu 0.865 mg/L,Mn 0.597 mg/L）,and the applicable water p H range was wide（p H:5-9）.The catalyst has higher catalytic activity,stable structure and good application potential.（3）The optimized MMCM spinel and LCMO perovskite catalysts were applied to degrade BPA in high salt environment.The effects of different types and concentrations of salt on the catalytic performance,and the influencing mechanism were investigated.The high chlorine environment was conducive to the degradation of BPA by MMCM/PDS and LCMO/PDS system.The stability of catalyst was not significantly affected under this condition,but the mineralization of pollutants was improved.High sulfate environment had slight inhibition on MMCM/PDS system,but had no effect on LCMO/PDS system.In the presence of high concentrations of carbonate and bicarbonate,the degradation of BPA was severely inhibited.