The controllable oxygen vacancies in N doped Bi2WO6-x for periodate activation: The synergy of superoxide and iodate radical

The activation of Periodate (PI) is widely recognized as an effective and cost-efficient method for pollutant removal. However, its applicability is constrained by its high selectivity. Nitrogen doped Bi2WO6 and its derivatives have been extensively applied for activating various oxidants for water remediation. However, the underlying mechanism of N-doped Bi2WO6 driven PI activation remains unclear. Herein, a novel nitrogen doped Bi2WO6 catalyst (N-BW) was prepared, and then oxygen vacancies (OVs) were successfully introduced into the N-BW via etching of the {WO4}2− layer through aqueous ammonia. An efficient photocatalytic activation system using N doped Bi2WO6-x and visible light (Vis) to activate PI for pollutant degradation (N-BWO/PI/Vis). In the 10 N-BWO/PI/Vis system, the tetracycline (TC) was eventually able to achieve a degradation rate of 82.58 %. Additionally, the N-BWO/PI/Vis system demonstrated good degradation performance over a wide pH range, different water matrices and in the presence of various ions. The system proved that OVs mediated superoxide radicals (O2−) activation could activate iodate radicals (IO3 and IO4) in PI and triggered the conversion of O2− to singlet oxygen (1O2). In conclusion, this study offers valuable insights for designing and applying modified bismuth tungstate in activating periodate for pollutant degradation. [Display omitted] •The nitrogen doped Bi2WO6 and ammonia etching regulates the oxygen vacancies.•The superoxide radicals and iodine radicals collaboratively degrade tetracycline.•The intermediate products and toxicity analysis showed it has potential application.•PI promotes the conversion of superoxide radicals (O2−) to singlet oxygen (1O2).