Diagnostics of the Structural and Transport Properties of an Anion-Exchange Membrane MA-40 after Use in Electrodialysis of Mineralized Natural Waters

Abstract

Changes in the structural and transport characteristics of MA-40 anion-exchange membranes after operation in industrial electrodialysis apparatuses have been assessed. Causes for the deterioration of operational properties by the action of various factors in the process of demineralization and concentration of natural waters have been revealed. Samples of the anion-exchange membrane after long-term operation in the working stack of an electrodialysis concentrator, as well as samples taken out from the electrode compartment of the electrodialysis reversal apparatus, have been studied. The most significant change in the structure of the membrane taken out from the electrodialyzer concentrator is an increase in macroporosity, which is the main reason for the growth in the electrical conductivity and water content against the background of a loss of ion-exchange capacity and selectivity. The formation of poorly soluble carbonates and hydroxides both on the surface and in the bulk of a membrane from the electrode compartment of the reversal electrodialyzer leads to the blocking of the functional groups and transport channels, decrease in electrical conductivity, and complication of transport processes.

Study of the Thermochemical Effect on the Transport and Structural Characteristics of Heterogeneous Ion-Exchange Membranes by Combining the Cell Model and the Fine-Porous Membrane Model

“…Therefore, changes in the properties of the studied membranes due to the influence of temperature, thermochemical, or current exposure were compared with these samples. The physicochemical properties of membrane samples of various types conditioned and thermostated at 20 • C in distilled water corresponded to the values known from the literature, for example [41,42].…”

Research on Membranes and Their Associated Processes at the Université Paris-Est Créteil: Progress Report, Perspectives, and National and International Collaborations

“…The microheterogeneous model developed by Gnusin, Nikonenko, Zabolotskii et al [ 59 , 144 ] seems to be the most suitable for real membrane systems. It is widely used in the literature [ 145 , 146 , 147 , 148 , 149 , 150 , 151 , 152 , 153 , 154 ] to interpret the experimental concentration dependences of membrane conductivity and diffusion permeability, and to determine the relationship of the “structure–transport properties” of IEMs. The model is based on a simplified representation of the IEM structure, according to which the membrane can be considered as a multiphase (in the simplest case, two-phase) system.…”

A Review on Ion-Exchange Membranes Fouling during Electrodialysis Process in Food Industry, Part 2: Influence on Transport Properties and Electrochemical Characteristics, Cleaning and Its Consequences

“…The microheterogeneous model developed by Gnusin, Nikonenko, Zabolotskii et al [68,74,93] seems to be the most suitable for real membrane systems. It is widely used in the literature [14,48,70,75,[94][95][96][97][98][99] to interpret the experimental concentration dependences of membrane conductivity, diffusion permeability, and to determine the relationship "structure-transport properties" of IEMs. The model is based on a simplified representation of the IEM structure, according to which the membrane can be considered as a multiphase (in the simplest case, two-phase) system.…”