关键词: 阿特拉津, 降解, Fe@Fe₂O₃纳米线, 分子氧活化, 铜离子

As a persistent chlorinated organic pollutant, Atrazine (2-chloro-4-(ethylamino)-6-isopropylamino-s-triazine) in the environment brings harm to natural environment as well as the human health. Since Atrazine is difficult to be degraded biologically, various strategies have been developed to realize efficient and environmentally-friendly removal of Atrazine. Recently, nanoscaled iron has been extensively applied for the remediation/treatment of wastewater contaminated with various organic and inorganic pollutants and exhibits superior activity than that of bulk iron. But its removal efficiency would decrease along with reaction time. In this study, we report that copper ions could efficiently promote atrazine degradation with Fe@Fe₂O₃ nanowires via the molecular oxygen activation processes. As indicated by the electron spin resonance analysis (ESR) and X-ray photoelectron spectroscopic analysis (XPS) results, the addition of Cu²⁺ ions could promote the release of dissolved Fe(Ⅱ) from Fe@Fe₂O₃. During the degradation process, the concentration of Fe(Ⅱ) in the solution with Cu²⁺ions is maintained at a much higher level than that without Cu²⁺ ions. At the same time, Cu²⁺ions were reduced to low valence states (Cu⁰), which further promoted the release of Fe²⁺. The generated Fe²⁺ would then activate the molecular oxygen via the single-electron or double-electron transfer route. As a result, more reactive oxygen species such as ·OH were generated to degrade atrazine. Under room temperature and aerobic condition, the Atrazine removal rate constant in Fe@Fe₂O₃/Cu²⁺ system was 0.694 h^-1, which was almost 23 times that in Fe@Fe₂O₃ system. Moreover, the Fe@Fe₂O₃/Cu²⁺catalytic system also remains superior activity in the pH range of 2~5. The intermediates of atrazine degradation were detected and the atrazine degradation in the Fe@Fe₂O₃/Cu²⁺ catalytic system was accompanied with alkylic oxidation, dealkylation and dechlorination. This study provides a new way to enhance molecular oxygen activation by core-shell Fe@Fe₂O₃ nanowires, and also deepens our understanding of the molecular oxygen activation processes by Fe@Fe₂O₃ for the aerobic pollutant degradation.

Key words: atrazine, degradation, Fe@Fe₂O₃ nanowires, molecular oxygen activation, copper ions