Solar-light-activated periodate for degradation and detoxification of highly toxic 6PPD-quinone at environmental levels

Abstract

Degradation and detoxication of highly toxic 6PPD-quinone remain great challenges due to its stable structure. Here we establish a solar-light-driven IO4− activation system for efficient degradation of 6PPD-quinone at environmental concentration levels (10–100 μg l−1), with residual concentration below 5.7 ng l−1 (detection limit) within 30 min. IO3• was determined as the primary reactive species after IO4− activation for cleavage of the highly toxic quinone structure. Single electron transfer is the most favourable route for IO3• attacking, in which single electrons achieve self-driven transfer from 6PPD-quinone to IO3• due to the maintenance of spatial inversion symmetry generated by dipole moments. Femtosecond transient absorption spectra confirmed the formation of 6PPD-quinone cationic radical (6PPD-quinone•+), which was the key reaction intermediate. This study proposes a promising technology for degradation and detoxification of highly toxic 6PPD-quinone in water and brings deep insight into the reaction mechanism within IO4− activation systems. There is a pressing need to develop effective treatment technologies for 6PPD-quinone, a newly discovered micropollutant, given its prevalent presence in water. The proposed advanced oxidation of IO4− activation under solar light irradiation achieves efficient degradation of 6PPD-quinone at environmental concentration levels.