Ion partitioning between brines and ion exchange polymers

POLYMER

卷:165

Article

Galizia, Michele¹  Manning, Gerald S.²  Paul, Donald R.³  Freeman, Benny D.^3,4 

[1] Univ Oklahoma, Sch Chem Biol & Mat Engn, 100E Boyd St, Norman, OK 73019 USA

[2] Rutgers State Univ, Dept Chem & Chem Biol, 610 Taylor Rd, Piscataway, NJ 08854 USA

[3] Univ Texas Austin, John J McKetta Jr Dept Chem Engn, 200 E Dean Keeton St, Austin, TX 78712 USA

[4] Univ Texas Austin, Ctr Energy & Environm Resources, 10100 Burnet Rd,Bldg 133 CEER, Austin, TX 78758 USA

关键词: Ion exchange polymers;    Brines;    Donnan model;   

DOI  :  10.1016/j.polymer.2019.01.026

来源: Elsevier

【 摘 要 】

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.

【 授权许可】

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