Sunlight-activated periodate oxidation: A novel and versatile strategy for highly efficient water decontamination

This study reported for the first time that the sunlight-activated periodate (PI) system could appreciably boost the selective abatement efficiency of emerging organic contaminants from the aqueous environment. The sunlight/PI system completely removed bisphenol F after 30 min, which was slightly affected by multiple coexisting water constituents, suggesting its selective oxidation characteristics. This combined system could also eliminate other micropollutants under simulated or natural sunlight irradiation. Multiple lines of evidence demonstrated the production of different oxidizing intermediates such as singlet oxygen (1O2), hydroxyl radicals, and superoxide radicals. Among these species, 1O2 was convincingly deemed as the predominant oxidizing species contributing to the exceptional elimination of different micropollutants. Additionally, PI was stoichiometrically transformed into the unharmful iodate ion without forming other iodine species. Product analysis of three model pharmaceuticals (methotrexate, propranolol, and sitagliptin) signified that the proposed oxidation system could introduce the degradation products of plausibly enhanced biodegradability. Notably, 30 min of sunlight/PI treatment could also efficiently eliminate micropollutants from the highly saline water and accomplish prominent water disinfection. Overall, the major contribution of this investigation is to provide a novel, highly efficient, selective, green, and versatile oxidation strategy for sustainable water purification using the chemical-free natural activator.