Study On The Degradation Of Sulfamethoxazole And Acetaminophen By PMS Activated With CoOOH@MXene

Pharmaceuticals and Personal Care Products（PPCPs）are a class of trace organic pollutants with stable chemical properties,strong bioaggregation and strong ecotoxicity.With the vigorous development of the chemical industry and biopharmaceutical industry in recent years,more and more emerging PPCPs have appeared in people’s field of vision and entered the organism through the food chain,which has a great impact on the health of the organism and the stability of the ecological environment.Therefore,it is urgent to explore a method removing PPCPs in the water environment,which is significantly important for the protection of water ecological environment.Advanced Oxidation Processes（AOPs）is a method to oxidatively degrade organics in water through the strong electron acquisition ability of strong oxidizing free radicals.It has high treatment efficiency,high speed,low secondary pollution and disposal conditions.Due to its mildness and other advantages,it has been widely used in the field of organic polluted water treatment and has become one of the research hotspots in this field.In this study,a CoOOH@MXene composite catalyst based on MXene was synthesized and used to activate peroxymonosulfate for the degradation of sulfamethoxazole and acetaminophen.The degradation performance of the catalytic system for two target pollutants was comprehensively evaluated,and the catalytic mechanism and degradation pathway were analyzed.In this study,using MXene as a substrate,novel CoOOH@MXene composite catalyst was prepared by a chemical precipitation method.The synthesized materials were characterized by SEM,TEM,XRD,FTIR,BET and XPS,which proved the successful preparation of CoOOH@MXene composites.Subsequently,the degradation performance of SMX and APAP by different catalytic systems was studied,and the initial p H,catalyst dose,PMS dose,pollutant concentration and coexisting ions were systematically investigated on the removal effect of SMX and APAP.In addition,the active species in the catalytic system were identified by quenching experiments and EPR spectroscopy,and the activity of each active radical in the degradation process was also determined.XPS was used to characterize the change of element valence before and after the reaction of the catalyst to infer the mechanisms of the degradation of SMX and APAP by the 1.3CoOOH@MXene/PMS system.Finally,the degradation intermediates were identified by LC-MS and the degradation pathways of SMX and APAP were proposed.The biotoxicity of the degradation products was evaluated by ECOSAR software.In SEM and TEM characterization,we can clearly see that CoOOH nanoparticles are uniformly loaded on the surface and interlayer of MXene,which preliminarily proves that this study successfully loaded CoOOH nanoparticles on MXene.There are not only characteristic diffraction peaks of MXene,but also characteristic diffraction peaks of CoOOH in the XRD and FTIR patterns,and the intensity of the characteristic peaks is gradually enhanced with the increase of CoOOH loading,which further proves the successful preparation of CoOOH@MXene composites.The test results of BET show that the specific surface area of CoOOH@MXene（183.82 m²/g）is much higher than that of CoOOH（85.36 m²/g）and MXene（6.89 m²/g）,which may be related to the good dispersibility of CoOOH nanoparticles in MXene.In XPS characterization,the XPS spectra of 1.3CoOOH@MXene did not change significantly before and after the catalytic reaction,proving that CoOOH@MXene prepared in this study has good physicochemical stability.In the degradation study of pollutants,the 1.3CoOOH@MXene/PMS system showed excellent degradation performance for SMX and APAP.The degradation rate of 1.3CoOOH@MXene/PMS system was 98.7%for SMX and 97.2%for APAP in 10min.The degradation process followed pseudo-first-order kinetic model well,and the rate constants of the 1.3CoOOH@MXene/PMS system for the degradation of SMX and APAP were 0.33 min^-1and 0.35 min^-1,respectively.Cycling experiments show that CoOOH@MXene has excellent reusability and stability.The results of quenching experiments and EPR characterization proved the existence of^·OH,SO₄^·-,O₂^·-and¹O₂in the catalytic system,and ¹O₂played a leading role in the degradation of pollutants.The XPS characterization results confirmed the Co（III）-Co（II）-Co（III）redox pair was involved in the degradation process.The degradation intermediates of SMX and APAP were identified by LC-MS,the degradation pathway and activation mechanism of SMX and APAP by CoOOH@MXene/PMS system were proposed.This study lays the foundation for the construction of MXene-based heterogeneous catalysts and their application in PMS activation,and provides ideas for the development of new catalysts in the field of environmental remediation.