Photodegradation of Sulfamethoxypyridazine in UV/Co(II)/Peroxymonosulfate System: Kinetics, Influencing Factors, Degradation Pathways, and Toxicity Assessment

Abstract

effect. Radical scavenger experiments indicated that hydroxyl radicals (HO • ) are prevailing active species responsible for SMP removal in UV/Co(II)/PMS system. The degradation of SMP in UV/Co(II)/PMS system was accomplished mainly by hydroxylation of the aromatic ring, extrusion of SO 2 , oxidation of NH 2 group, and N − S bond cleavage. Eight intermediates for SMP degradation were identified, and their toxicities to aquatic organisms were predicted by using the ECOSAR program based on the structure − activity relationships (SARs), which suggested that the chronic toxicities of SMP and its degradation intermediates are more significant than their acute toxicities. The present research indicates that UV/Co(II)/ PMS system is applicable for SMP degradation in aqueous solutions and may be helpful to understand the transformation behavior of SAs.