Degradation of antibiotic sulphamethoxazole by application of modified photo-Fenton processes: kinetics, degradation pathways and toxicity

Degradation of antibiotic sulphamethoxazole (SMX) was studied by applying modified photo-Fenton reactions (MPF) with the novel choice of using sodium tripolyphosphate (STP) and sodium hexametaphosphate (SHP) complexing agents. STP and SHP have a strong ability as complexing agents because they can sequester and complex with different ions. Process optimisation was performed using Doehlert design at pH = 6. This study presented higher performance for MPF using STP and SHP complexing agents than conventional photo-Fenton and H2O2 + UV process. The best yields were associated with the formation of a smaller number of intermediates with high degradation efficiency and low oxidative stress, environment-friendly and promising processes.