화학공학소재연구정보센터
Catalysis Today, Vol.335, 485-491, 2019
Photocatalytic fuel cell based on sulfate radicals converted from sulfates in situ for wastewater treatment and chemical energy utilization
Sulfate is a primary component of industrial wastewater and the existing wastewater treatment methods cannot effectively recover the chemical energy of pollutants. Sulfate radicals (SO4-center dot), as a strong oxidant, have obvious advantages in the degradation of refractory pollutants compared with hydroxyl radicals (HO center dot). In this study, a novel photocatalytic fuel cell (PFC) is first proposed for the treatment of sulfate-rich organic wastewater, in which sulfates can be converted in situ easily into sulfate radicals to degrade organics in wastewater while generating electricity. Sulfate radicals dominating the oxidation reaction of the PFC system are confirmed by the free-radical capture reaction. Furthermore, the results of the present study show that various model compounds and actual wastewater can be used as substrates in the PFC system. For instance, methyl orange, a typical refractory organic, exhibits excellent electricity generation with a short-circuit current density of 3.72 mA cm(-2), open-circuit voltage of 1.32 V, and a maximum power-density output of 1.68 mW cm(-2). Meanwhile, the degradation efficiency of methyl orange reached 74.2% after 4 h in the PFC system. The PFC system used self-bias photoanode consisting of a front photoanode of WO3 and a rear photocathode of Si photovoltaic cell (Si PVC), which could accelerate the speed of charge separation and increase the electron transfer rate of the PFC cell. Therefore, the proposed PFC system provides great potential for resourceful utilization of sulfate-rich organic wastewater and chemical energy recycling.