Degradation of pyrazole wastewater by electro-peroxone with fluidized N-doped electrodes: Dual-zone synergistic catalytic reaction

The electro-peroxone (E-P) technology exploits in-situ generated H2O2 to drive the peroxone reaction, which not only improves degradation efficiency but also utilizes wasted O2 in the process of O3 generation. However, limited by the cathodic interface reaction, a quantity of O3 diffused into the bulk solution could not be effectively utilized. To address this problem, a dual-zone E-P process was proposed in combination with nitrogen-doped granular activated carbon (GAC(N)) and a 2 electron-oxygen reduction reaction (2e-ORR) system, i.e., the EGAC(N)-P system. Combining EPR and quenching experiments, the addition of GAC(N) was proven to alter the & sdot;OH-dominated reaction routine of E-P to the & sdot;OH and & sdot;O2 - synergistic routine, which achieved a high pollutant removal efficiency of up to 98.75 % and a reaction rate constant of 0.3838 min-1 (3.5 times that of the traditional E-P system). In terms of the mineralization mechanism, the E-GAC(N)-P system not only effectively inhibited the accumulation of intermediate products but also increased the total organic removal by 63.94 %. Moreover, the efficient removal of COD in actual wastewater also confirmed that the E-GAC(N)-P system had excellent mass transfer efficiency and 36.9 % lower electric energy consumption than did the traditional E-P system, indicating good practical application prospects.