Boron promoted Fe^(3+)/peracetic acid process for sulfamethazine degradation:Efficiency,role of boron,and identification of the reactive species

摘要

In this work,boron(B)was used to promote Fe^(3+)/peracetic acid(Fe^(3+)/PAA)for the degradation of sulfamethazine(SMT).An SMT degradation efficiency of 9.1%was observed in the Fe^(3+)/PAA system over 60 min,which was significantly increased to 99.3%in the B/Fe^(3+)/PAA system over 10 min.The B/Fe^(3+)/PAA process also exhibited superior resistance to natural substances,excellent adaptability to different harmful substances,and good removal of antibiotics in natural fresh water samples.The mechanism of action of boron for Fe^(3+)reduction was determined using scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),Fourier transform infrared(FT-IR)spectroscopy,density functional theory(DFT)calculations,and electrochemical tests.The dominant role of^(·)OH was confirmed using quenching experiments,electron spin resonance(EPR)spectroscopy,and quantitative tests.Organic radicals(R-O^(·))and Fe(IV)also significantly contribute to the removal of SMT.DFT calculations on the reaction between Fe^(2+)and the PAA were conducted to further determine the contribution from ^(·)OH,R-O^(·),and Fe(IV)from the perspective of thermodynamics and the reaction pathways.Different boron dosages,Fe^(3+)dosages,and initial pH values were also investigated in the B/Fe^(3+)/PAA system to study their effect of SMT removal and the production of the reactive species.Fe(IV)production determined the k_(R-O·+Fe(IV))value suggesting that Fe(IV)may play a more important role than R-O^(·).A comparison of the results with other processes has also proved that the procedure described in this study(B/Fe^(3+)/PAA)is an effective method for the degradation of antibiotics.