Efficient Degradation of Norfloxacin and Simultaneous Electricity Generation in a Persulfate-Photocatalytic Fuel Cell System

Photocatalytic fuel cell (PFC) has been verified to be a promising technique to treat organic matter and recover energy synchronously. Sulfate radicals (SO4-), as a strong oxidant, have obvious advantages in the degradation of refractory pollutants compared with hydroxyl radicals (center dot OH), which is the dominant radical in PFC. This study reports a coupling method of PFC and persulfate (PS) activation to promote the degradation of antibiotic norfloxacin (NOR) and simultaneous electricity generation. The added PS as an electron acceptor could be activated by photoelectric effects to produce SO4 center dot- at the electrodes-electrolyte interface. In the solution, PS as supporting electrolyte could accelerate the electron transfer and also be activated by ultraviolet (UV) light irradiation, which could extend the radical oxidation reaction to the whole solution and improve the PFC performance. The performance comparison among different systems indicated the excellent synergistic effect of PFC and PS activation for improving NOR degradation and electricity generation. The effects of influencing factors including initial pH, PS concentration, and initial NOR concentration on the degradation of NOR were investigated extensively to find out the optimal conditions. Moreover, according to the results of radical capture experiments, the significantly contribution of both SO4 center dot- and center dot OH to the degradation of NOR was demonstrated and a tentative function mechanism for the NOR degradation in the proposed system was provided. Finally, total organic carbon and real wastewater treatment confirmed the high mineralization and practical applicability of the proposed PFC/PS system.