Activated carbon fiber (ACF) was used as electrochemical cathode to activate persulfate (PS, includes peroxydisulfate (PDS) and peroxymonosulfate (PMS)) to remove refractory organic pollutants in water. The E-ACF-PS systems had a synergistic effect on the degradation of carbamazepine (CBZ). Compared with E-ACF-PDS system, E-ACF-PMS had higher CBZ mineralization efficiency and lower energy consumption. According to radical trapping experiments and the evaluation of relative contribution, hydroxyl radical played an important role in the degradation of CBZ in E-ACF-PMS system, while in E-ACF-PDS system, sulfate radical was dominant. Besides, singlet oxygen was confirmed by electron paramagnetic resonance (EPR) test in E-ACF-PMS system. Different from other PMS activation processes, the generation pathway of singlet oxygen in E-ACF-PMS was mainly due to the reaction between hydroxyl radical and PMS at ACF cathode. The intermediates of CBZ in E-ACF-PS systems were detected, and toxicological experiments showed that the reaction solution treated with E-ACF-PMS system had less inhibition on the growth of microcystis aeruginosa. The difference of degradation pathways of CBZ between the two systems was possibly due to the oxidation of singlet oxygen. According to SEM, BET, and FT-IR analyses, the pore structure and surface functional groups of ACF cathode were protected by electric field even after 50 recycles. Experiments were also conducted to study the effects of different water matrices and the removal efficiency of other persistent organic pollutants, including nitrobenzene (NB), sulfamethoxazole (SMX), diclofenac (DC), and tetracycline (TC). The above results demonstrated that in E-ACF-PS systems, compared with PDS, PMS could create a more efficient, sustainable, and lower energy consumption process for water treatment.

Removal of carbamazepine from aqueous solution by electrochemical activation of persulfate with ACF cathode: Comparison between peroxydisulfate and peroxymonosulfate

ACS Fall 2020 Virtual Meeting

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