Electric field induced activated carbon fiber (ACF) cathode transition from an initiator/a promoter into an electrocatalyst in ozonation process

Abstract

Removal of nitrobenzene (NB), a carcinogenic and refractory pollutant, in aqueous solution by adsorption, ozonation, electrolysis, and electro-peroxone (E-peroxone) with activated carbon fiber (ACF) was investigated, respectively. Kinetic analyses of NB removal by all the processes followed pseudo-first-order kinetics and the Kapp of E-peroxone-ACF was 14.90×10−2min−1, which was much higher than the others. Besides, the Kapp of E-peroxone-ACF process reduces slightly to 12.18×10−2min−1 even after 100 times of ACF recycle, showing a sustainable activity. Moreover, according to the pore texture characteristics, surface functional groups, FTIR, and SEM images, E-peroxone process does not considerably alter the ACF surface, whereas ozone alone can cause substantial damage to it. These results suggested that ACF was induced from an initiator/a promoter into an electrocatalyst in ozonation by free electrons injection. Moreover, comparing with titanium cathode, ACF can remarkably improve the removal of NB in E-peroxone due to the synchronous adsorption of pollutants and ozone as well as the enhancement of H2O2 generation. It indicates that the ACF cathode is a promising material for organic pollutants removal in the E-peroxone process.