Fenton-Like Degradation Comparison of s-Triazine Herbicides in Aqueous Medium

Fenton-like degradation of three representative s-triazine herbicides, atrazine (Atz), ametryn (Amt), and prometon (Prt), was studied in this work. The effects of initial H2O2 concentration as well as the Fe3+ concentration on the degradation rate of the herbicides were investigated. The Fenton-like degradation of the s-triazine herbicides fitted well with pseudo first-order kinetics. LCMS-IT-TOF was used to analyze possible degradation intermediates for the three herbicides. Eleven, eleven, and twelve intermediates were identified for Atz, Amt, and Prt, respectively. According to the identified intermediates, the Fenton-like degradation pathways of Atz, Amt, and Prt were proposed, which were suggested to follow two main routes, alkylic oxidation and hydroxylation substitution. The enhanced electron-donating ability of the s-triazine herbicide benefits both degradation reaction routes. Therefore, Amt gives the highest reactivity, while Atz exhibits the highest resistance among three herbicides to the Fenton-like reaction.