Transport and Electrochemical Characteristics of CJMCED Homogeneous Cation Exchange Membranes in Sodium Chloride, Calcium Chloride, and Sodium Sulfate Solutions.

Veronika Sarapulova,Valentina Titorova,Victor Nikonenko,Tongwen Xu,Dmitrii Butylskii,Natalia Pismenskaya,Yang Zhang,Yaoming Wang

doi:10.3390/membranes10080165

Abstract

Recently developed and produced by Hefei Chemjoy Polymer Material Co. Ltd., homogeneous CJMC-3 and CJMC-5 cation-exchange membranes (CJMCED) are characterized. The membrane conductivity in NaCl, Na2SO4, and CaCl2 solutions, permeability in respect to the NaCl and CaCl2 diffusion, transport numbers, current–voltage curves (CVC), and the difference in the pH (ΔpH) of the NaCl solution at the desalination compartment output and input are examined for these membranes in comparison with a well-studied commercial Neosepta CMX cation-exchange membrane produced by Astom Corporation, Japan. It is found that the conductivity, CVC (at relatively low voltages), and water splitting rate (characterized by ΔpH) for both CJMCED membranes are rather close to these characteristics for the CMX membrane. However, the diffusion permeability of the CJMCED membranes is significantly higher than that of the CMX membrane. This is due to the essentially more porous structure of the CJMCED membranes; the latter reduces the counterion permselectivity of these membranes, while allowing much easier transport of large ions, such as anthocyanins present in natural dyes of fruit and berry juices. The new membranes are promising for use in electrodialysis demineralization of brackish water and natural food solutions.

Highlights

Ion-exchange membranes (IEMs) have been widely used in capacitive deionization [1], electrolysis [2], Donnan [3] and neutralization dialysis [4], fuel cells [5,6], and bioelectrochemical systems [7]
We report the results of a study of the transport characteristics and current–voltage curves of cation-exchange membranes
The distance, b, between the levels corresponding to the top of the “hills” and the bottom of the “valleys” (Figure 2b) of the CJMC-3 surface is about 35 μm, which is comparable with the value of this parameter for the CMX membrane, b = 45 ± 10 μm [68]

Summary

Introduction

Ion-exchange membranes (IEMs) have been widely used in capacitive deionization [1], electrolysis [2], Donnan [3] and neutralization dialysis [4], fuel cells [5,6], and bioelectrochemical systems [7] They are utilized for extracting valuable components, such as ammonia, along with producing electricity [8], and in other applications. Electrodialysis (ED) is a traditional area of their application In this process, under the action of an electric field applied by two electrodes, cations are removed from the feed solution through cation-exchange membranes (CEMs) permeable nearly exclusively to cations, and the anions are removed through anion-exchange membranes (AEMs). ED is used to produce table salt [10], denitrify drinking water [11], isolate nutrients and organic compounds from their salt solutions [12,13,14], and to produce high-quality drinking water and water for irrigation in areas with insufficient rainfall [15]

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