Fe3+/Fe2+ cycle promoted peroxymonosulfate activation with addition of boron for sulfamethazine degradation: Efficiency and the role of boron

Abstract

Boron was used as an environmentally friendly and efficient reductant to accelerate the recycle of Fe2+ enhancing peroxymonosulfate (PMS) activation for sulfamethazine (SMT) degradation. The SMT removal was only 28.1% within 30 min in Fe2+/PMS system while SMT removal could reach to 98.9% within only 3 min in Boron/Fe2+/PMS (B/Fe2+/PMS). Electron paramagnetic resonance spectroscopy (EPR) tests, quantitative detection and radical quenching experiments illustrated that OH and SO4− played important role and Fe(IV), 1O2 and O2− also participated in SMT removal. The addition of boron could enhance the role of OH and SO4− in SMT removal in Fe2+/PMS system. X-ray photoelectron spectroscopy (XPS), electrochemical tests and density functional theory (DFT) calculation were conducted to confirm the mechanism of boron for accelerating the recycle of Fe2+. Possible SMT degradation pathway was proposed. B/Fe2+/PMS process could efficiently remove SMT at low Fe2+ dosage and neutral pH. B/Fe2+/PMS system also exhibited a superior resistance to inorganic ions and nature organic matters. Moreover, B/Fe2+/PMS system had good applicability to different pollutants, excellent reusability for antibiotics removal, and efficient performance for removing antibiotics in nature fresh water. The results compared with others’ works also demonstrated the present study process was a promising strategy for antibiotics removal.