Assessment of Glucocorticoid Removal by UVA/Chlorination and Ozonation: Performance Comparison in Kinetics, Degradation Pathway, and Toxicity

Glucocorticoids (GCs) have drawn great concern due to widespread contamination in the environment and application treating COVID-19. This work aimed compare performance of UVA/chlorination ozonation on GC removal terms efficiency, degradation pathway, toxicity change, with fluocinolone acetonide (FA), triamcinolone (TA), clobetasol propionate (CP) as target compounds. The results showed that both could degrade GCs. Compared (removal efficiency 89% for FA, 86% TA, 90% CP at 7 h), 96% 98% 15 min) was more effective removal. Photodegradation contributed most during UVA/chlorination, while O3 molecules were main functional species ozonation. H-abstraction, dechlorination, carbon–carbon bond cleavage, ester hydrolysis proposed based identification intermediates. However, ozone tended attack C=C double bonds, resulting cracked benzene ring GCs, chlorine likely alcohol ketone groups. Although GCs removed their acute toxicities slightly declined. reduction.