Mineralization of sulfamethizole in photo-Fenton and photo-Fenton-like systems

In this investigation, UV/H₂O₂, UV/H₂O₂/Fe²⁺ (photo-Fenton) and UV/H₂O₂/Fe³⁺ (photo-Fenton-like) systems were used to mineralize sulfamethizole (SFZ). The optimal doses of H₂O₂ (1–20 mM) in UV/H₂O₂ and iron (0.1–1 mM) in photo-Fenton and photo-Fenton-like systems were determined. Direct photolysis by UV irradiation and direct oxidation by added H₂O₂, Fe²⁺ and Fe³⁺ did not mineralize SFZ. The optimal dose of H₂O₂ was 10 mM in UV/H₂O₂ and that of iron (Fe²⁺ or Fe³⁺) was 0.2 mM in both UV/H₂O₂/Fe²⁺ and UV/H₂O₂/Fe³⁺ systems. Under the best experimental conditions and after 60 min of reaction, the SFZ mineralization percentages in UV/H₂O₂, UV/H₂O₂/Fe²⁺ and UV/H₂O₂/Fe³⁺ systems were 16, 90 and 88%, respectively. The UV/H₂O₂/Fe²⁺ and UV/H₂O₂/Fe³⁺ systems effectively mineralized SFZ.