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

In this investigation, UV/H2O2, UV/H2O2/Fe(2+) (photo-Fenton) and UV/H2O2/Fe(3+) (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, Fe(2+) and Fe(3+) did not mineralize SFZ. The optimal dose of H2O2 was 10 mM in UV/H2O2 and that of iron (Fe(2+) or Fe(3+)) was 0.2 mM in both UV/H2O2/Fe(2+) and UV/H2O2/Fe(3+) systems. Under the best experimental conditions and after 60 min of reaction, the SFZ mineralization percentages in UV/H2O2, UV/H2O2/Fe(2+) and UV/H2O2/Fe(3+) systems were 16, 90 and 88%, respectively. The UV/H2O2/Fe(2+) and UV/H2O2/Fe(3+) systems effectively mineralized SFZ.