Ni(II) induced aerobic ring opening degradation of atrazine with core-shell Fe@Fe2O3 nanowires

In general, the final product of atrazine (ATR) degradation by reactive oxygen species is cyanuric acid bearing a stable s -triazine ring, which is not further oxidized under mild conditions. In this study, we demonstrate that the presence of Ni(II) can increase the aerobic ATR degradation rate of core–shell Fe@Fe 2 O 3 nanowires (CSFN) by 6 times and also achieve the cleavage of recalcitrant s -triazine ring. The cleavage of s -triazine ring in this novel system was confirmed by the measurements of formic acid and nitrite acid. On the basis of experimental results, a feasible mechanism was proposed to account for the promoted aerobic ATR degradation and the facile s -triazine ring cleavage as follows. First, Ni(II) adsorbed on the surface of CSFN was reduced to nickel metal, which favored the generation of active hydrogen (•H). The in-situ generated •H then reduced ATR to 4-ethylamino-6-isopropylamino-1,3,5-triazine intermediate of easy ring opening property, rather than the recalcitrant cyanuric acid. Finally, this ATR degradation pathway change promoted the aerobic ATR degradation and benefited the s -triazine ring cleavage. This study clarifies the importance of degradation pathway on the ring-opening of organic pollutants, and also provides a mild method to remove s -triazine herbicides with molecular oxygen and zero-valent iron.