Photoreduction of atrazine from aqueous solution using sulfite/iodide/UV process, degradation, kinetics and by-products pathway

Due to its widespread use in agriculture, atrazine has entered aquatic environments and thus poses potential risks to public health. Therefore, researchers have done many studies to remove it. Advanced reduction process (ARP) is an emerging technology for degrading organic contaminants from aqueous solutions. This study was aimed at evaluating the degradation of atrazine via sulfite/iodide/UV process. The best performance (96% of atrazine degradation) was observed in the neutral pH at 60 min of reaction time, with atrazine concentration of 10 mg/L and concentration of sulfite and iodide of 1 mM. The kinetic study revealed that the removal of atrazine was matched with the pseudo-first-order model. Results have shown that reduction induced by \({{\text{e}}}_{{\text{aq}}}^{-}\) ${\text{e}}_{\text{aq}}^{-}$ and direct photolysis dominated the degradation of atrazine. The presence of anions ( \({{\text{Cl}}}^{-}\) ${\text{Cl}}^{-}$ , \({{\text{CO}}}_{3}^{2-}\) ${\text{CO}}_3^{2-}$ and \({{\text{SO}}}_{4}^{2-}\) ${\text{SO}}_4^{2-}$ ) did not have a significant effect on the degradation efficiency. In optimal conditions, COD and TOC removal efficiency were obtained at 32% and 4%, respectively. Atrazine degradation intermediates were generated by de-chlorination, hydroxylation, de-alkylation, and oxidation reactions. Overall, this research illustrated that Sulfite/iodide/UV process could be a promising approach for atrazine removal and similar contaminants from aqueous solutions.