Preparation And Properties Of Sulfonated TiO₂/PVDF-g-PSSA Nanocomposite Membrane

As a new biological treatment technology,Microbial fuel cell(MFC)has attracted the attention of researchers.Proton exchange membrane as an important part of MFC,has become the focus of researchers.In the research,the inorganic titanium dioxide(TiO2)and the polyvinylidene fluoride graft Sodium p-styrenesulfonate(PVDF-g-PSSS)were modified by physical blending.The TiO2/PVDF-g-PSSA composite membrane was prepared by solvent evaporation method.The structure and properties of TiO2/PVDF-g-PSSA membrane were tested.By using infrared spectroscopy(FT-IR),compared to PVDF-g-PSSS(PS)membrane,TiO2/PVDF-g-PSSA composite membrane at 614 cm-1 appears Ti-O-Ti characteristic peaks.TiO2/PVDF-g-PSSA composite membrane was successfully prepared.X-ray diffraction(XRD)tested membrane.The role of adding TiO2 on the PVDF crystal is not big.But the proportion of amorphous region expanded,the crystallinity decreased.With the increase of TiO2,hydrophilicity and mechanical properties of the membranes were improved,but the ion exchange capacity and proton conduction rate decreased slightly.The good proton conductivity of TiO2/PVDF-g-PSSA composite membrane is more than 0.04S/cm,so the composite membrane has better performance is 1% TiO2.To improve the proton conductivity of the composite,Sulfonation of TiO2(TiO2-SO3H)was obtained by sulfonating TiO2.The TiO2-SO3 H powder was mixed with PVDF-g-PSSS polymer to obtain the composite membrane.Tested the performance of TiO2-SO3H/PVDF-g-PSSA composite membrane.FT-IR and X-ray photoelectron spectroscopy(XPS)analysis chemical composition and membrane surface elements of TiO2-SO3 H powder.Compared to TiO2,TiO2-SO3 H powder appears S=O and S-O bond peak,XPS showed the obvious peak of S element.FT-IR and XPS showed sulfonation successfully.SEM tested 1%TiO2/PVDF-g-PSSA composite membranes?PS membranes and TiO2-SO3H/PVDF-g-PSSA composite membranes.The surface morphology has little change.But the pore density of TiO2-SO3H/PVDF-g-PSSA membranes becomes significantly larger,more uniform pore dispersion.XRD showed that the addition of TiO2-SO3 H powder has little effect on the crystal structure of PVDF.The amorphous area ratio increased,the crystallinity decreased.Adding different proportions of TiO2-SO3 H powder,hydrophilicity?proton conductivity and mechanical properties of the membrane first increased and then decreased.When the TiO2-SO3 H content is 5%,the moisture content of the composite membrane reaches to 40.98%,the proton conductivity can reach 0.0537S/cm,and the mechanical properties are the best.Applying the TiO2-SO3H/PVDF-g-PSSA composite membrane,PS membrane and DuPont N117 membrane to the MFC.Testing some performance of MFC system.Resistance and the removal rate of COD of TiO2-SO3H/PVDF-g-PSSA composite membrane and PS membrane in MFC system was higher than N117 membrane system,power density and CE value is lower.The cost of TiO2-SO3H/PVDF-g-PSSA composite membrane is small,and power density?resistance and CE are close to the N117 membrane.TiO2-SO3H/PVDF-g-PSSA composite membrane has a great prospect in application.