Simultaneous regeneration of p-nitrophenol-saturated activated carbon fiber and mineralization of desorbed pollutants by electro-peroxone process

This study investigated the regeneration of p-nitrophenol (PNP) saturated activated carbon fiber (ACF) by a novel electro-peroxone (E-peroxone) approach, which aimed to simultaneously regenerate exhausted ACF and mineralize desorbed pollutants by coupling conventional cathodic regeneration with ozonation. PNP-saturated ACF was attached to a carbon-polytetrafluorethylene cathode, which was then applied a current to drive cathodic desorption of pre-loaded PNP and electrochemical generation of H2O2 from O2 in the sparged ozone generator effluent (O2 and O3 gas mixture). The electro-generated H2O2 then reacts with sparged O3 to yield OH, which can rapidly mineralize the desorbed pollutants (PNP and its derivatives). After 3 h regeneration, the E-peroxone process restored ∼95% of the ACF adsorption capacity, and effectively mineralized the desorbed pollutants. In addition, the E-peroxone regeneration did not considerably modify the structural and chemical properties of ACF. Consequently, the ACF exhibited no evident decline in the adsorption capacity after twelve cycles of PNP adsorption and E-peroxone regeneration. These results indicate that the E-peroxone regeneration can successfully achieve the goal of simultaneous regeneration of saturated ACFs and mineralization of desorbed pollutants, and may thus provide an attractive and viable alternative for the regeneration of organic-saturated ACs.