Effect of Water Content on Sodium Chloride Sorption in Cross-Linked Cation Exchange Membranes

Journal Article · Wed Mar 13 00:00:00 EDT 2019 · Macromolecules

DOI:https://doi.org/10.1021/acs.macromol.8b02550· OSTI ID:1566547

Jang, Eui-Soung ^[1]; Kamcev, Jovan ^[1]; Kobayashi, Kentaro ^[1]; Yan, Ni ^[1]; Sujanani, Rahul ^[1]; Talley, Samantha J. ^[2]; Moore, Robert B. ^[2]; Paul, Donald R. ^[1]; Freeman, Benny D. ^[1]

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1. Univ. of Texas, Austin, TX (United States). McKetta Dept. of Chemical Engineering, Texas Materials Inst., Center for Energy and Environmental Resources, and Center for Research in Water Resources
2. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States). Dept. of Chemistry, Macromolecules Innovation Inst.

Ion exchange membranes used for energy generation and water purification selectively transport ions, and this characteristic is strongly influenced by ion sorption in such membranes. Although water content and fixed charge group concentration are key factors affecting ion sorption in ion exchange membranes, their individual effects on ion sorption are not often studied. Here, a series of cross-linked cation exchange membranes (CEMs) were synthesized with different water uptake values and similar fixed charge group concentrations to study the effect of water content on ion sorption in such materials. Equilibrium co-ion concentrations in all membranes were very similar at a given external salt concentration, suggesting that co-ion sorption in these materials was mainly influenced by fixed charge group concentration rather than water content per se. Equilibrium co-ion sorption data were interpreted using a thermodynamic model based on Donnan theory and Manning’s counterion condensation theory. The inhomogeneous morphology of the membranes was characterized by small-angle X-ray scattering (SAXS). The Manning parameter was used as an adjustable constant to account for morphological heterogeneity. The Manning parameter was less than the critical value for these CEMs, suggesting no counterion condensation occurred. Good agreement was observed between the model and experimental co-ion sorption data.

• Research Organization: Univ. of Texas, Austin, TX (United States); Energy Frontier Research Centers (EFRC) (United States). Center for Materials for Water and Energy Systems (M-WET)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Grant/Contract Number: SC0019272
• OSTI ID: 1566547
• Journal Information: Macromolecules, Journal Name: Macromolecules Journal Issue: 6 Vol. 52; ISSN 0024-9297
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
catalysis (heterogeneous)
charge transport
materials and chemistry by design
membranes
mesoscale science
mesostructured materials
separations
synthesis (novel materials)
synthesis (predictive)
synthesis (self-assembly)
water