Citrate iron complex induced dramatically enhanced oxidation of atrazine with bimetallic Bi/Fe0: Reactivity, oxidation and mechanism

Abstract

The oxidative degradation of atrazine (ATR) using bimetallic Bi/Fe⁰ nanoparticles cooperated with citric acid (CA) and sodium citrate (NaCA) without extra addition of H₂O₂ or another oxidant was conducted. Almost 73% of ATR was removed in Bi/Fe⁰+NaCA + CA buffer system in 3 h, and the bimetallic Bi/Fe⁰ performs high stability and long service life in the buffer system according to the results of cyclic degradation experiments. The citrate iron complex of Fe(II)[Cit]^- played the key role for the degradation process since it could quickly react with the generated H₂O₂ to produce free radicals in the Bi/Fe⁰+NaCA + CA system, which broadened the applicable pH range of the traditional Fenton reaction and promoted the oxidative degradation process of ATR. The possible degradation pathways of ATR were also investigated. In the Bi/Fe⁰+NaCA + CA buffer system, twelve kinds of ATR intermediate products were detected, of which the main products were dechlorination products and alkyl oxidative products. Due to the pH controllable of the Bi/Fe⁰+NaCA + CA system, it could reduce the acidity impact on the environment and makes the additional impact on the environment lower. Therefore, this work provides a new strategy for the degradation of ATR.

Keywords: Atrazine; Bi/Fe(0); Citrate iron complex; Oxidation.