A novel advanced oxidation process using iron electrodes and ozone in atrazine degradation: Performance and mechanism

Abstract

In this work, iron electrode was employed to enhance the reactivity of ozone (EC/O3) in atrazine degradation. Compared to ozonation and Fe2+-catalyzed ozonation, the elimination rate of atrazine by the EC/O3 process increased significantly with increasing applied currents. The simultaneous formation of hydroxyl radical (OH) and ferryl ion (Fe(IV)) from the reaction between ozone and in-situ formed Fe2+ was proposed and experimentally confirmed. The second order rate constant for atrazine reacting with Fe(IV) was estimated to be 125M−1s−1 using a relative rate method. The individual roles of the reactive species (OH, Fe(IV), and O3) in atrazine degradation were modeled using a kinetic model and OH was the predominant reactive species in the EC/O3 system. Furthermore, the effects of water quality parameters, such as initial pH and natural organic matters (NOM), on the performance of EC/O3 process were also evaluated. The results demonstrated that higher initial pH is favorable for ozone consumption and atrazine degradation. The presence of NOM appreciably inhibited the degradation of atrazine, which may be attributed to the competition of NOM for OH. This study provides a new approach to enhance ozonation, and broadens the knowledge of ozonation in removing organic contaminants from water.