The roles of alkali metal counter-ions of PFSA play in the formation of PVDF/PFSA-M hollow fiber membranes

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• 作者：Wan-Zhong Lang^a ; ^{wzlang@shnu.edu.cn} ; Qin Ji^a ; Jian-Ping Shen^a ; Ya-Jun Guo^a ; Zhen-Liang Xu^b
• 关键词：Polyvinylidenefluoride (PVDF) ; Perfluorosulfonic acid (PFSA) ; Hollow fiber membrane ; Ultrafiltration
• 刊名：Desalination
• 出版年：2012
• 期刊代码：24_00119164
• 类别：ce
• 出版时间：16 April, 2012
• 卷：292
• 期：Complete
• 页码：45-52
• 文件大小：1684 K

摘要

The aim of the present study was to thoroughly investigate the effect of alkali metal counter-ions (Li, Na, K and Rb) of PFSA on the formation, morphology and performances of polyvinylidenefluoride (PVDF)/perfluorosulfonic acid (PFSA-M) hollow fiber membranes. It is found that the homogeneous region in the ternary phase diagram of the PVDF-PFSA-M/NMP/H₂O systems shrinks and the precipitation rate increases when varying the counter-ions of PFSA in the order of Li, Na and K. The double finger-like structure and the cavities can be evidently developed with increasing the radius of the counter-ions of the spun PVDF/PFSA-M membranes. The pure water permeability (J_W) and mean effective pore size of the PVDF/PFSA-M membranes first increase from counter-ion Li, Na to K and then slightly decrease for Rb. In addition, the highest J_W value of 96.5 L M^鈭?#xA0;2 H^鈭?#xA0;1 bar^鈭?#xA0;1 was obtained for the PVDF/PFSA-K membrane with a MWCO of 86 kDa. XRD patterns and FTIR-ATR spectra verify the exclusive formation of 尾 crystalline phase structure in the as-spun PVDF/PFSA-M membranes. The PVDF/PFSA-Li membrane has better Young's modulus and tensile strength than that of other PVDF/PFSA-M fibers.