CFD simulation of mass transfer in electrochemical reactor with mesh cathode for higher phenol degradation

Abstract

Cathode, where electro-catalytic oxidation barely took place, could exert a significant influence on electro-catalytic efficiency, whereas little investigation has been focused on this effect. In this study, the effect of cathode configuration on electro-catalytic activities was investigated with phenol as model pollutant, and the mechanism was revealed from the perspective of mass transfer with computational fluid dynamics (CFD) simulation. Compared with the planar Ti cathode, the electro-catalytic reactor with mesh Ti exhibited 1.21–1.26 times faster phenol degradation rate under various testing inlet flow rates. CFD simulation revealed the higher velocity distribution both in the reactor and on anode surface when meshed Ti cathode was used, which benefited faster fluid flow so that the pollutant transfer was accelerate especially at higher inlet flow rate. Excellent agreement of mass transfer between CFD simulation and experimental analysis was achieved, the mass transfer coefficient with mesh Ti was 1.40–1.55 times of the case with planar cathode under various inlet flow rates. The enhanced mass transfer performance was mainly ascribed to the rhombic pores of mesh cathode where hydrogen bubbles generated on would escape timely and randomly at various directions, leading to the disturbance of fluid flow around the anode. This study highlighted mesh cathode played a key role in improving pollutant degradation, and CFD, as a versatile and convenient tool to analyze the hydrodynamic behavior of electro-catalytic reactor, showed a strong persuasion to guide the optimization of electrode configuration.