Co-ion specific effect on sodium halides sorption and transport in a cross-linked poly(p-styrene sulfonate-co-divinylbenzene) for membrane applications

Journal Article · Thu Oct 01 00:00:00 EDT 2020 · Journal of Membrane Science

DOI:https://doi.org/10.1016/j.memsci.2020.118410· OSTI ID:1673772

Galizia, Michele ^[1]; Paul, Donald R. ^[2]; Freeman, Benny D. ^[3]

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1. Univ. of Oklahoma, Norman, OK (United States); The University of Texas at Austin
2. Univ. of Texas, Austin, TX (United States)
3. Univ. of Texas, Austin, TX (United States); Center for Materials for Water and Energy Systems (M-WET), Austin, TX (United States)

Here, sodium halide sorption and transport in a cation exchange membrane based on cross-linked poly(p-styrene sulfonate-co-divinylbenzene) (CR61) were investigated experimentally and theoretically. At fixed co-ion valence, sodium halide partitioning between aqueous electrolyte solutions and ion exchange polymers is only minimally sensitive to co-ion chemical identity. NaCl, NaF and NaI exhibit similar solubility coefficients in CR61, which agrees reasonably well with predictions of the Donnan-Manning model, especially at high external salt concentrations. Ion activity coefficients in the membrane were evaluated and ion sorption thermodynamics were investigated. Ion diffusion coefficients in CR61 were predicted using a recently developed framework based on the Manning diffusion model, which accounts for electrostatic effects on ion diffusion, and the Mackie-Meares model, which accounts for tortuosity/area effects on ion diffusion in swollen polymers. Model predictions agree reasonably well with the experimental data, especially at high external salt concentrations. The observed decrease in salt diffusion coefficients in CR61 relative to values in aqueous solutions is due primarily to tortuosity/area effects. Salt diffusion coefficients correlate with co-ion hydrated radius and membrane water content. Finally, salt permeability coefficients predicted using the solution-diffusion model exhibit good agreement with experimental data, especially at external salt concentration greater than 0.1 mol/L.

• Research Organization: Univ. of Texas, Austin, TX (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0019272
• OSTI ID: 1673772
• Alternate ID(s): OSTI ID: 1640232
• Journal Information: Journal of Membrane Science, Journal Name: Journal of Membrane Science Vol. 612; ISSN 0376-7388
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
Ion sorption
Ion-exchange membrane
Salt diffusion
Water purification