Transport Characteristics of CJMAED™ Homogeneous Anion Exchange Membranes in Sodium Chloride and Sodium Sulfate Solutions

Veronika Sarapulova; Natalia Pismenskaya; Valentina Titorova; Mikhail Sharafan; Yaoming Wang; Tongwen Xu; Yang Zhang; Victor Nikonenko

doi:10.3390/ijms22031415

Transport Characteristics of CJMAED™ Homogeneous Anion Exchange Membranes in Sodium Chloride and Sodium Sulfate Solutions

Int J Mol Sci. 2021 Jan 31;22(3):1415. doi: 10.3390/ijms22031415.

Authors

Veronika Sarapulova¹, Natalia Pismenskaya¹, Valentina Titorova¹, Mikhail Sharafan¹, Yaoming Wang², Tongwen Xu², Yang Zhang³, Victor Nikonenko¹

Affiliations

¹ Membrane Institute, Kuban State University, 149 Stavropolskaya St., 350040 Krasnodar, Russia.
² CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, School of Chemistry and Material Science, University of Science and Technology of China, Hefei 230026, China.
³ School of Environmental and Safety Engineering, Qingdao University of Science and Technology, 53 Zhenzhou Road, Qingdao 266042, China.

Abstract

The interplay between the ion exchange capacity, water content and concentration dependences of conductivity, diffusion permeability, and counterion transport numbers (counterion permselectivity) of CJMA-3, CJMA-6 and CJMA-7 (Hefei Chemjoy Polymer Materials Co. Ltd., China) anion-exchange membranes (AEMs) is analyzed using the application of the microheterogeneous model to experimental data. The structure-properties relationship for these membranes is examined when they are bathed by NaCl and Na₂SO₄ solutions. These results are compared with the characteristics of the well-studied homogenous Neosepta AMX (ASTOM Corporation, Japan) and heterogeneous AMH-PES (Mega a.s., Czech Republic) anion-exchange membranes. It is found that the CJMA-6 membrane has the highest counterion permselectivity (chlorides, sulfates) among the CJMAED series membranes, very close to that of the AMX membrane. The CJMA-3 membrane has the transport characteristics close to the AMH-PES membrane. The CJMA-7 membrane has the lowest exchange capacity and the highest volume fraction of the intergel spaces filled with an equilibrium electroneutral solution. These properties predetermine the lowest counterion transport number in CJMA-7 among other investigated AEMs, which nevertheless does not fall below 0.87 even in 1.0 eq L^-1 solutions of NaCl or Na₂SO₄. One of the reasons for the decrease in the permselectivity of CJMAED membranes is the extended macropores, which are localized at the ion-exchange material/reinforcing cloth boundaries. In relatively concentrated solutions, the electric current prefers to pass through these well-conductive but nonselective macropores rather than the highly selective but low-conductive elements of the gel phase. It is shown that the counterion permselectivity of the CJMA-7 membrane can be significantly improved by coating its surface with a dense homogeneous ion-exchange film.

Keywords: anion exchange membrane; diffusion permeability; electric conductivity; modification; permselectivity; structure–properties relationship.

MeSH terms

Anions / chemistry*
Chlorides / chemistry
Diffusion
Electric Conductivity*
Ferric Compounds / chemistry
Hyaluronic Acid / chemistry
Ion Exchange
Membranes, Artificial*
Permeability
Sodium Chloride / chemistry
Sulfates / chemistry
Water / chemistry

Substances

Anions
Chlorides
Ferric Compounds
Membranes, Artificial
Sulfates
intergel
Water
sodium sulfate
Sodium Chloride
Hyaluronic Acid

Grants and funding

20-08-0093/Russian Foundation for Basic Research