Activation Of Peroxymonosulfate By A Bimetallic Sulfide For Degradation Of Bisphenol A And Its Mechanism Study

Because sulfate radicals have strong oxidizing ability(E=2.5-3.1eV)and wide pH adaptation range,their application in water treatment has been attracted more and more attention.The SO4·-was mainly produced by activating persulfate(PS)and persulfate(PMS).There are many ways of activating PMS,such as thermal activation,base activation,and transition metal activation.Transition metal activation is a common method of activating PMS.This dissertation studied the new system which the activation of PMS mediated by bimetallic sulfide,and studied the role of sulfur in the catalytic process.The main research contents are as follows:(1)Chalcopyrite nanoparticles(CuFeS2 NPs)were successfully prepared and characterized.It was used as a catalyst for peroxymonosulfate(PMS)activation to degrade BPA.The effects of reaction parameters such as initial pH,catalyst concentration,PMS concentration,initial BPA concentration and reaction temperature on BPA degradation in CuFeS2-PMS system were investigated.It was found that under the condition of 0.1g L-1 CuFeS2 and 0.3mmol L-1 PMS,20 mg L-1 BPA was almost completely degraded(99.7%)in 20 min and could achieve 75%mineralization removal.Compared with Cu2S,FeS2,CuFe02 and Co304,CuFeS2 exhibits ultra-high activity for PMS activation.The XPS characterization of fresh and used CuFeS2 found that the high catalytic activity of CuFeS2 was closely related to two aspects:on the one hand,S2-promotes the circulation of Fe3+/Fe2+ and Cue+/Cu+ on the surface of the catalyst,and on the other hand,the synergistic effect of Fe3+/Fe2+ and Cue+/Cu+cycling in PMS activation.(2)S-doped CoFe2O4(CoFe2O4/S)was successfully prepared,and its phase composition and surface composition were determined by XRD and XPS.The results show that S was successfully doped into CoFe2O4 and did not affect the crystal structure of CoFe2O4.The degradation of BPA in CoFe2O4/S-PMS and CoFe2O4-PMS systems was compared.It was found that the pseudo second-order kinetic constant of CoFe2O4/S-PMS was 3.55 times that of CoFe2O4-PMS.When the dosage of CoFe2O4/S and PMS was 0.1 g L-1 and 0.3 mmol L-1,20 mg L-1 BPA degraded completely within 10 min.The results of electron paramagnetic resonance(EPR)and quenching experiments confirmed that active species were sulfate radical(SO4·-)and hydroxyl radical(·OH).The XPS analysis of fresh and used catalyst showed that the high activity of CoFe2O4/S on PMS was attributed to the common catalytic effect of Co2+and Fe2+ on the surface,and the corresponding reaction mechanism was proposed.