Persulfate activation using Co/AC particle electrodes and synergistic effects on humic acid degradation

The activation of persulfate (PS) was proposed using Co/AC particle electrode. Degradation of humic acid (HA) confirmed that PS can be activated even under 0.67 mA cm−2. The synergistic effect between PS-based and Co/AC electrochemical oxidation reduced the PS dosage, hydraulic retention time, and current density. PS dosing neutralized the effluent, overcoming the problem of alkaline effluent. Moreover, the negative effect of NO3− was eliminated due to PS dosing. Electron spin resonance detection illustrated that OH was generated and dominated in the process of PS activation. PS also promoted the production of atomic H* in Co/AC bed, and improved the stability of active species. Quenching experiments of radicals revealed that HA degradation was mainly fulfilled by the OH and SO4− radicals that were adsorbed on the particle electrodes. Cyclic voltammetry curves indicated that PS dosing increased the overpotential for oxygen evolution of Co/AC electrode, inhibiting the side reaction of oxygen.