Ion partitioning between brines and ion exchange polymers

Journal Article · Fri Feb 01 04:00:00 EST 2019 · Polymer

DOI:https://doi.org/10.1016/j.polymer.2019.01.026· OSTI ID:1566477

Galizia, Michele; Manning, Gerald S.; Paul, Donald R.; Freeman, Benny D.

Quantitative failure of the ideal Donnan model to predict ion partitioning between relatively dilute electrolyte aqueous solutions and ion exchange polymers arises from neglecting non-ideal behavior of ions. Hypothetically, when a water swollen, charged polymer is equilibrated with concentrated salt solutions, most of the fixed charge groups are neutralized by sorbed counter-ions, which can screen electrostatic effects and create, in the membrane, an environment thermodynamically similar to that experienced by ions in the external electrolyte solution. In this study, a combined experimental and theoretical approach was used to test this hypothesis. A fundamental study of ion partitioning between a cation exchange membrane based on cross-linked poly(p-styrene sulfonate-co-divinylbenzene) and NaCl and CaCl2 concentrated brines is presented. At high electrolyte concentrations, the experimentally measured ion activity coefficients in the membrane match those in the contiguous external solution, and the ideal Donnan model provides an accurate prediction of co-ion and counter-ion concentrations in the polymer. This physical picture was further confirmed by the recently developed Manning-Donnan model.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Center for Materials for Water and Energy Systems (M-WET); Univ. of Texas, Austin, TX (United States)
• Sponsoring Organization: USDOE SC Office of Basic Energy Sciences (SC-22)
• DOE Contract Number: SC0019272
• OSTI ID: 1566477
• Journal Information: Polymer, Journal Name: Polymer Journal Issue: C Vol. 165; ISSN 0032-3861
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

catalysis (heterogeneous)
charge transport
materials and chemistry by design
membranes
mesoscale science
mesostructured materials
separations
synthesis (novel materials)
synthesis (predictive)
synthesis (self-assembly)
water