Mineralization and photodegradation of oxytetracycline by UV/H2O2/Fe2+ and UV/PS/Fe2+ process: quantification of radicals

In this study, different oxidation processes UVA-365 nm (photolysis), UV–A/H2O2, UV–A/H2O2/Fe2+, UV–A/S2O8, and UV–A/S2O8/Fe2+ were investigated to compare removal rates efficiencies of Oxytetracycline (OTC). The role the initial concentration oxidants, as well their inhibitory threshold regarding degradation mineralization OTC, was at pH. It found that pH solution had an important in photolysis since alkaline solutions, rate faster than acidic but terms yield, it did not exceed 3%. addition oxidants (H2O2, S2O8) impact on mineralization, which reached 50% for UV/S2O8 system. To improve ferrous ions added UVA/oxidants, leading 85% mineralization. Quantification main radicals involved process can help understanding free radical mechanism respective contributions OTC. ability Dimethylsulfoxide (DMSO) act a scavenger considered UV/H2O2 UV/H2O2/Fe2+ systems. hydroxyl react directly with DMSO produce stable intermediate, methanesulfonate. Otherwise, isopropanol, tert-butanol 1,4, benzoquinone used indirect methods catch quantify generated during UV/S2O8/Fe2+processes. Finally, results allowed each photo-oxidation both systems, UV/ S2O8.