Integrating Catalytic Electrode In Bioelectrochemical System For Cost-effective VOCs Treatment

Emissions of volatile organic compounds?VOCs?could worsen air quality and adversely affect human health.To eliminate VOCs pollutants to harmless level,several purification technologies have been developed and used to control VOCs pollution.However,each of these technologies has its own problems that limit and restrict their application and performance.Thus,developing more efficient low temperature VOCs removal techniques will be of great significance.Controlling VOCs pollution in the air is beneficial to protect human health.In this thesis,a novel VOCs treatment system integrating membrane separation and photo-electrochemical catalysis with microbial fuel cell?PEC-MFC?was established for promoting continuous removal of VOCs.Moreover,with combination of peroxymonosulfate?PMS?activation process,PMS/PEC-MFC system was firstly designed and established.This system was proved as an efficient way for gaseous toluene treatment and electricity generation.The experimental results are summarized as follows:?1?CeO₂/TiO₂ composites were successfully prepared by a sol-gel method.The XRD pattern of TiO₂ and CeO₂ can be indexed to the anatase and cubic crystalline phase,respectively.XPS analysis confirmed that the formation of Ti-O bond and the existence of Ce³⁺/Ce⁴⁺on the surface of CeO₂/TiO₂ composites.According to UV-vis spectra,the band gap of TiO₂ and CeO₂ were 3.0 eV and 2.9 eV,respectively.In addition,using activated carbon fiber felt?ACF?with superior conductivity as the electrode substrate,CeO₂/TiO₂/ACF catalytic cathode was obtained.?2?The hallow chamber polyvinylidene fluoride/carbon fiber cloth?PVDF/CFC?membrane was prepared and set in the anode of coupling system.SEM image shows that the PVDF layer was uniformly attached to carbon fiber cloth and there are no pores on the surface.Thus,this PVDF/CFC membrane can be used as a VOCs enrichment/diffusion layer.?3?PEC-MFC system shows excellent elimination capacities?EC?for ethyl acetate?⁰.39 g/m³,EC:².52 g/m³?h?or toluene?⁰.29-4.10 g/m³,EC:¹.89-28.04 g/m³?h?under UV illumination at room temperature.The electron paramagnetic resonance?EPR?tests confirm the existence of·OH and·O₂^-on the surface of catalytic cathode.?4?PMS/PEC-MFC system exhibits high efficiency in toluene removal?EC:².80g/m³?h?and stable power output?cell voltage:0.40 V?.EPR tests show that both·OH and·SO₄^-are involved in toluene removal with the addition of PMS,where·SO₄^-plays a predominant role.