Toxicity changes of dye degradation via photo-fenton treatment and the possible degradation mechanism

This study investigates the photo-Fenton process's efficacy in degrading three textile dyes: acid red 52 (AR52), reactive orange 16 (RO16), and direct red 28 (DR28). AR52 undergoes rapid, complete decolorization with an 82% reduction in Total Organic Carbon (TOC), indicating non-toxic byproduct formation. In contrast, DR28 shows limited decolorization (55%), minimal TOC reduction (1%), and increased toxicity post-treatment. RO16 excels with complete decolorization and a 93% TOC reduction, suggesting near-total mineralization. Despite initial toxicity differences, AR52 and RO16 exhibit reduced toxicity after 90 minutes, while DR28's toxicity slightly increases. Proposed degradation pathways elucidate varied dye responses, underscoring the photo-Fenton process's complexity in mitigating toxicity.