| 质子传导膜内受限空间离子扩散过程 |
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| 引用本文： | 青格乐图,宋士强,范永生,王保国.质子传导膜内受限空间离子扩散过程[J].化工学报,2013,64(2):689-695. |
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| 作者姓名： | 青格乐图 宋士强 范永生 王保国 |
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| 作者单位： | 清华大学化学工程系,化学工程联合国家重点实验室,北京 100084 |
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| 基金项目： | 化学工程联合国家重点实验室2011年自主课题立项支持，国家自然科学基金项目，国家重点基础研究发展计划项目 |
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| 摘 要： | 以具有纳米尺度孔径的聚偏氟乙烯(PVDF)质子传导膜为对象,研究电解质溶液中水合离子在受限空间内的传递行为,证明使用纳米尺度多孔膜代替离子交换膜用于液流电池过程的可行性。利用渗透实验分别研究浓度场、压力场,以及不同渗透压条件下膜中离子扩散和水迁移现象,分析传质行为与膜结构和组成之间的关系。结果表明离子在纳米尺度孔径的PVDF膜中的扩散过程与溶液中类似,表观离子扩散系数不受浓度差推动力的影响;离子交换膜中的表观离子扩散系数随浓度差推动力提高而增加。在渗透压作用下,自制PVDF纳米孔膜的水迁移速率低于Nafion 117膜,水迁移带来的负面影响更小;对于H+/VO2+的离子选择系数超过300,有效透过H+而阻止VO2+,适用于全钒液流电池过程。
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| 关 键 词： | 全钒液流电池 质子传导 离子扩散系数 受限空间 膜结构 |
| 收稿时间： | 2012-07-31 |
| 修稿时间： | 2012-09-03 |
Ion diffusion behaviors through porous proton conductive membrane |
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| QING Geletu
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SONG Shiqiang
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FAN Yongsheng
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WANG Baoguo.Ion diffusion behaviors through porous proton conductive membrane[J].Journal of Chemical Industry and Engineering(China),2013,64(2):689-695. |
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| Authors: | QING Geletu SONG Shiqiang FAN Yongsheng WANG Baoguo |
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| Affiliation: | State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China |
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| Abstract: | To prove the feasibility that nano-scale porous membrane can replace ion exchange membrane used for vanadium redox flow battery(VRB), mass transfer of hydrated-ion in electrolyte solution through a limited space formed by PVDF nano-porous proton conductive membranes was studied.On a self-designed ion diffusion cell, NaCl and water permeation processes were measured under given concentration and hydrodynamic gradient, as well as osmotic pressure.The results obtained can be applied to correlate mass transport behaviors with membrane morphology.The results show that the behavior of ion diffusion through nano-scale limited space is similar to that in a bulk electrolyte solution; apparent diffusion coefficients are independent of ion concentration.In contrast, apparent diffusion coefficients of ion permeation through ion exchange membrane obviously increase with concentration gradient.For a given osmotic pressure, PVDF nano-porous proton conductive membranes have smaller water permeation rate than that of Nafion 117, and negative influence is also much smaller.Self-made PVDF proton conductive membrane can effectively reject VO2+, providing selectivity over 300 for H+/VO2+ electrolyte at ambient temperature, which means that it is possible to replace ion exchange membrane in flow battery application. |
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| Keywords: | all-vanadium redox flow battery proton conduction ion diffusion coefficient limited space membrane morphology |
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