Oxidation of atrazine in aqueous media by solar- enhanced Fenton-like process involving persulfate and ferrous ion

•A significant synergistic effect was observed for solar-enhanced S2O82−/Fe2+ system.•Solar/S2O82−/Fe2+ treatment resulted in 100% ATZ removal and 20% TOC reduction.•ATZ toxicity was reduced to non-toxic levels.•In situ generated SO4-• and •ОН radicals were the major reactive species.

The oxidation of s-triazines (using atrazine (ATZ) as a model compound) by a solar-enhanced Fenton-like process involving persulfate and ferrous ion was studied. A flow-through tubular photoreactor was employed for the experiments. The solar-enhanced oxidative system involving ferrous ion and persulfate (Solar/S2O82−/Fe2+) showed the highest ATZ degradation efficiency when compared with other treatments (unactivated S2O82−, Solar - sunlight only, S2O82−/Fe2+, Solar/S2O82−). Complete degradation of ATZ and 20% reduction in total organic carbon (TOC) content were observed after 30 min of the treatment. The in situ generated •ОН and SO4-• radicals were shown to be involved in ATZ oxidation using the radical scavengers methanol and tert-butyl alcohol. Furthermore, iron compounds were shown to act not only as catalysts but also as photo-sensitizers, as the introduction of ferrous ion into the reaction mixture led to an increased absorbance of the solution and expansion of the absorption spectrum into the longer wavelength spectral region.