Enhanced degradation of acid orange 74 via anodic activation of peroxydisulfate using a silver nanoparticle-modified carbon paper anode

Abstract

In this study, peroxydisulfate (PDS) was activated using silver nanoparticle-modified carbon paper (AgNPs@CP) anode for the efficient degradation of acid orange 74 (AO 74) in wastewater. The AgNPs@CP anode degraded AO 74 at a 4.96-fold higher rate than the unmodified CP anode, where the degradation efficiency depended mainly on radical oxidation, with ·OH accounting for 63.50% and SO4·− accounting for 16.02%. The current density and PDS concentration were the most important parameters affecting the activation efficiency, and the degradation rate could be quantitatively controlled by adjusting these parameters. In terms of the effect of water matrices, Cl− considerably improved the electrochemical activation efficiency, whereas CO32− and PO43− inhibited it. After five cycles of reuse, the AO 74 degradation efficiency decreased to 88.39%, and the corresponding degradation rate decreased to 30.56% of the original value. However, the AO 74 degradation efficiency was still substantially higher than that achieved by the unmodified CP anode. The main reason for the deactivation of the AgNPs@CP electrode was the formation of Ag2+ during electrochemical activation. Generally, the anodic activation of PDS using the AgNPs@CP anode is an efficient method for degrading refractory organic pollutants.