In this study, the feasibility of two heterogeneous catalysis (non-Fenton heterogeneous catalysis and catalytic ozonation) was evaluated for the oxidative transformation of the fungicide procymidone and its major metabolite (3,5-dichloroaniline; 3,5-DCA) under a pilot lab experiment. Among the studied treatments, only H2O2 or O3 significantly oxidized procymidone and 3,5-DCA. However, heterogeneous catalysis used with various types of MnO2 catalysts was found to be an effective rapid strategy for transformation of procymidone and its aniline metabolite. Among the studied catalysts, δ-MnO2 performed well in the enhanced oxidative transformation of procymidone and 3,5-DCA in MnO2-mediator system assay. The optimal reaction parameters, such as reaction pH, and initial catalyst concentration were comparatively evaluated. However, heterogeneous catalysis and catalytic ozonation were revealed as the rapid strategy for oxidative transformation of investigated procymidone and 3,5-DCA as compared to single oxidation by peroxide/ozone. Finally, as a novel insight of this investigation, a postulated reaction mechanism underlying the accelerated transformation of aniline metabolites via heterogeneous catalysis was explored. The findings of this study will open new avenues for evaluating heterogeneous catalysis during oxidative transformation of non-phenolic pollutants in both lab trial and field applications. This study can be expanded for use in actual field settings, using environmental samples from contaminated areas exposed to non-phenolic pesticides and their metabolites.
Keywords: 3,5-Dichloroaniline; Catalytic ozonation; Heterogeneous catalysis; MnO2 catalyst; Oxidative transformation; Procymidone.
© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.