Sulfonamides degradation assisted by UV, UV/H2O2 and UV/K2S2O8: Efficiency, mechanism and byproducts cytotoxicity.

The objective of this study was to analyze the effectiveness of UVC, UVC/H2O2 and UVC/K2S2O8 on the degradation of SAs. Rate constant values increased in the order SMZ < SDZ < SML and showed the higher photodegradation of sulfonamides with a penta-heterocycle. Quantum yields were 1.72 × 10-5 mol E-1, 3.02 × 10-5 mol E-1, and 6.32 × 10-5 mol E-1 for SMZ, SDZ and SML, respectively, at 60 min of treatment. R254 values show that the dose habitually utilized for water disinfection is inadequate to remove this type of antibiotic. The initial sulfonamide concentration has a major impact on the degradation rate. The degradation rates were higher at pH 12 for SMZ and SML. SMZ and SML photodegradation kλ values are higher in tap versus distilled water. The presence of radical promoters generates a greater increase in the degradation rate, UVC/K2S2O8 cost less energy, a mechanism was proposed, and the degradation by-products are less toxic than the original product.