Theoretical and experimental study on the degradation mechanism of atrazine in Fenton oxidation treatment

Abstract

The residues of atrazine in surface and ground water will cause harm to human health as they are slowly biodegraded microbiologically. In this work, density functional theory (DFT) and the polarizable continuum model (PCM) were used to investigate the degradation of atrazine in an aqueous medium by Fenton oxidation technology. The results show that H atom abstraction pathways are more probable than both OH radical addition and Cl atom substitution pathways. Moreover, the H atom abstraction from the –CH– of –CH(CH₃)₂ group and –CH₂– of –CH₂CH₃ group are expected to occur more easily. New dealkylation and alkyl oxidation mechanisms are proposed, in which water can act as a catalyst to reduce the reaction barrier dramatically. The stable intermediates and products: CH₃COCH₃, DEDIA, DIA, DEA, CAFT, CDAT, CDET, CDFT and CFIT, have been identified with LC/MS analysis. This study offers a cost-effective way to probe the degradation mechanism of atrazine in an aqueous medium by Fenton oxidation technology.