초록 |
In this study, partially fluorinated cation exchange membranes were prepared by direct sulfonation of poly(VDF-co-hexafluoropropylene) copolymers (PVDF-co-HFP) by a casting method. Structure of the sulfonated PVDF-co-HFP (SPVDF) was confirmed by Fourier-transform infrared (FT-IR) and 1H Nuclear magnetic resonance (1H NMR) analysis. X-ray Photoelectron spectroscopy (XPS) was used to confirm the chemical composition. The membrane properties such as water uptake, ion exchange capacity and electrical resistance were measured. It was suggested that the optimum direct sulfonation condition of PVDF-co-HFP ion exchange membranes was 60°C and 7 hours for temperature and duration of sulfonation, respectively. The water uptake of the SPVDF ion exchange membrane was 21.5%. The ion exchange capacity and electrical resistance were 0.89 meq/g and 3.70 Ω⋅cm2, respectively. In the MCDI process, the maximum salt removal rate was 62.5% in repeated absorption-desorption cycles. |