Research On Organic Wastewater Treatment By Coupling Method Photocatalytic Fuel Cell And Persulfate

The photocatalytic fuel cell（PFC）is promising owing to the capability of synchronous organic pollutants removal and energy recycle,but it still has some defects,such as low processing efficiency and long reaction time.In this paper,a coupling method introducing persulfate（PS）into PFC system was proposed.This method could expand redox reaction from the electrodes surface to the total cell space,improving the degradation of organic wastewater and simultaneous electricity production.In this study,the coupling PFC/PS system was used TiO₂ as photoanode and Pt as cathode,because TiO₂ has good stability,non-toxicity,low cost and good light responsiveness.The synergistic systems were established by adding perfluorosulfate（PMS）and peroxodisulfate（PDS）into PFC to degrade the typical organic pollutants,such as methyl orange（MO）,tetracycline（TC）and reactive brilliant blue（KN-R）.The electricity production was also measured for these systems.The specific contents are as follows:（1）A TiO₂/Ti photoanode was prepared by electrochemical anodization.The X-ray diffraction,scanning electron microscopy and X-ray energy dispersive spectroscopy indicated that TiO₂/Ti photoanode with nanotube array structure were successfully synthesized on titanium sheets.（2）MO was selected as the target pollutants,and the degradation and power generation of PFC/PDS were investigated.Under the optimal conditions,the decolorization efficiency of MO and the electricity production were 40.36%and 44.97%relative to the PFC system without adding PS,respectively.The radicals scavenging tests confirmed that SO₄^·ˉand HO^·were the main reactive species in PFC/PDS.（3）TC was selected as the target pollutants,and the degradation and power generation performance of PFC/PMS were studied.Under the optimal conditions,the degradation rate of TC and the electricity production were 82.83%and 122.40%versus that of traditional PFC,respectively.A series of radicals scavenging experiments manifested that SO₄^·ˉand HO^·were the main oxide species at acidic conditions,the direct oxidation of PMS was played the key roles at the neutral environment,and ¹O₂ and O₂^·ˉdominated the primarily effect in the alkaline circumstance.（4）The KN-R degradation and synchronous electricity production were investigated in PFC/PMS and PFC/PDS systems,respectively.Under the optimal conditions,the KN-R removal rate in the PFC/PDS system was greater than that of PFC/PMS.In contrast,the power generation of PFC/PMS system was better than PFC/PDS.Furthermore,the radical scavenging experiments identified that HO^·,SO₄^·ˉand ¹O₂ were chief active species in the PFC/PMS,and HO^·,SO₄^·ˉand O₂^·ˉwere acted significant roles in the PFC/PDS.In addition,the natural organic matter（HA）and anions(Cl^-,HCO₃^-,NO₃^-and HPO₄^2-)in the water body had an important impact on the cell performance of the PFC/PS system.