Overlooked involvement of phosphate radicals in the degradation of the atrazine herbicide by sulfate radical-based advanced oxidation

The persistence of recalcitrant pollutants in water is a major health issue calling for advanced and green techniques to clean polluted waters. For instance, direct activation peroxydisulfate by visible light without any catalyst displays remarkable potential degrade water, the involved reactive species pure conditions with deionized have been elucidated recently. However, impact phosphates, which are commonly abundant real waters, on performance this reaction still unclear, possible formation secondary phosphate radicals has yet be clarified. Here we studied effect degradation atrazine under light. Radicals were electron paramagnetic resonance. Results show that 10 mM as H2PO4−/HPO42− decreased pseudo-first-order rate constant 47.6% peroxydisulfate/visible system at pH 7.0. kinetics correlated linearly concentration was dependent. Optimal efficiency achieved 7.0, while higher significantly impeded degradation. These results suggest inhibitory due less radicals. This hypothesis supported reduced peak intensities Our findings imply presence phosphates could highly decrease pollutant removal situations.