Discrepant oxidation behavior of ferric ion and hydroxyl radical on syringic acid and vanillic acid in atmospheric Fenton-like system

Syringic acid (SA) and vanillic acid (VA) from biomass combustion are not only the potential sources of atmospheric brown carbon (BrC) but also the traceable markers of biomass burning in smoke particles. In this work, the Fenton-like oxidation in a mixed system containing SA and VA was studied under some typical conditions in atmospheric aqueous. The influence of scavenger, Fe3+ concentration, H2O2 concentration, SA concentration, pH and oxygen was discussed. Our results revealed that despite SA and VA have similar structures, Fe3+ and HO center dot sever as their main oxidation sources, respectively. The addition of SA could heighten the HO center dot yield obviously compared with conventional Fenton-like oxidation in atmospheric water, and this performance was attributed to the strong reducibility to Fe3+. In addition, SA accelerated the oxidation of VA and caused a 4.7-fold elevation in the initial rate. These results demonstrate that the process may change the amount of SA and VA and then disturb their mass ratio, which is important for aerosol source characterization work.

Automated summary

This study investigated the Fenton-like oxidation in a mixed system containing SA and VA in atmospheric aqueous, revealing that the addition of SA increased the HO center· yield and accelerated the oxidation of VA, potentially altering the mass ratio of SA and VA.