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

• Boron significantly promoted Fe 2+ /PMS process for SMT removal. • DFT calculation was conducted to confirm the role of boron. • OH, SO 4 − , Fe(IV), 1 O 2 and O 2 − all participated in SMT removal. • B/Fe 2+ /PMS process could efficiently remove SMT at low Fe 2+ dosage and neutral pH. • B/Fe 2+ /PMS process showed a better performance in removing antibiotic in nature fresh water. Boron was used as an environmentally friendly and efficient reductant to accelerate the recycle of Fe 2+ enhancing peroxymonosulfate (PMS) activation for sulfamethazine (SMT) degradation. The SMT removal was only 28.1% within 30 min in Fe 2+ /PMS system while SMT removal could reach to 98.9% within only 3 min in Boron/Fe 2+ /PMS (B/Fe 2+ /PMS). Electron paramagnetic resonance spectroscopy (EPR) tests, quantitative detection and radical quenching experiments illustrated that OH and SO 4 − played important role and Fe(IV), 1 O 2 and O 2 − also participated in SMT removal. The addition of boron could enhance the role of OH and SO 4 − in SMT removal in Fe 2+ /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 Fe 2+ . Possible SMT degradation pathway was proposed. B/Fe 2+ /PMS process could efficiently remove SMT at low Fe 2+ dosage and neutral pH. B/Fe 2+ /PMS system also exhibited a superior resistance to inorganic ions and nature organic matters. Moreover, B/Fe 2+ /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.