Degradation of trans-ferulic acid in aqueous solution by a water falling film DBD reactor: Degradation performance, response surface methodology, reactive species analysis and toxicity evaluation

In this study, a water falling film dielectric barrier discharge (DBD) reactor was used to degrade trans-ferulic acid (FA) in water. The results show that 98.4% of FA was degraded by 10 min treatment with the discharge voltage of 19 kV. The reactor displayed an excellent energy efficiency, which could reach to 13.4 g/kWh for FA degradation. Degradation characteristics of the water falling film DBD for FA was studied by single factor experiments and response surface methodology. The optimal operating condition and a quadratic polynomial equation for predicting FA degradation efficiency were obtained by the response surface model. The reactive species analysis unveils that the peroxone reaction between H 2 O 2 and O 3 generated by DBD could promote the formation of OH, causing a synergistic effect for FA degradation. Hydrated electron (e aq − ) converted into H in FA solution. In the present reaction system, H preferred to react with FA rather than merge with OH, and H showed a well ability to degrade FA. FA solution toxicity was weakened after DBD treatment.