Complementarity and action mechanisms of Fe2+ activated persulfate and
H2O2 system
Abstract
The Fe2+ activated persulfate and H2O2 (Fe2+/KPS/H2O2) system achieved
94% removal of four mixed sulfonamides with 300 s treatment and
possessed excellent complementarity and stability in a wide of pH (3 –
11) and temperature (5 – 65 ℃). The quenching and electron spin
resonance spectrometer results confirmed that sulfate radicals and
hydroxyl radicals coexisted in the coupled system and were responsible
for eliminating sulfonamides under ambient conditions. Experimental
determination and density functional theory calculations demonstrated
that the reaction rate constants of sulfate radicals and hydroxyl
radicals at possible reactive sites distinguished the difference in
removal ratios of four sulfonamides. The removal ratio of sulfathiazole
was higher than others because its calculated reaction rate constants of
sulfate radicals and hydroxyl radicals were higher than those of
sulfamerazine, sulfamethoxazole, and sulfamethazine. The finding
provided a reference for investigating the removal mechanism of mixed
organic pollutants when multiple free radicals coexist.