Novel composite cation exchange films based on sulfonated PVDF for electromembrane separations

• Published in: Journal of membrane science 2015-01, Vol.474, p.167-174
• Main Authors: Farrokhzad, H., Kikhavani, T., Monnaie, F., Ashrafizadeh, S.N., Koeckelberghs, G., Van Gerven, T., Van der Bruggen, B.
• Format: Article
• Language: English
• Subjects: Cation exchange membrane (CEM); Cation exchanging; Composite membrane; Differential scanning calorimetry; Electrodialysis; Exchange; Ion exchange capacity (IEC); Ion exchangers; Membranes; Polyvinylidene fluorides; Sulfonated PVDF (S-PVDF); Transport; Uptakes
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2014.10.002

A novel cation exchange membrane (CEM) composed of a blend of polyvinylidene fluoride (PVDF) and sulfonated PVDF (S-PVDF) was prepared. The membranes were prepared with different fractions of S-PVDF to optimize performance in desalination. The sulfonated polymer was characterized by FTIR, HNMR, DSC and TGA. The membrane properties such as ion exchange capacity (IEC), transport number, morphology, permselectivity, ion conductivity, water uptake, contact angle and electrodialysis (ED) performance were evaluated. Polymer characterization proved the sulfonation of PVDF and the degree of sulfonation was estimated. With increasing S-PVDF fractions, the transport number and permselectivity decreased while the IEC and ion conductivity increased. Finally, the salt extraction in ED obtained for a 70% S-PVDF membrane was 67.6%, which is a better performance than that of a commercial membrane. •A novel composite membrane based on sulfonated PVDF was synthesized.•Sufonation was proved by FTIR and its degree was estimated by TGA and HNMR.•Sulfonation decreased the thermal stability and melting point of PVDF.•IEC and conductivity were varied against the permselectivity in membranes.•The membrane with 70% S-PVDF gave a better performance than a commercial membrane.