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

Abstract

Ion-exchange membranes (IEMs) are increasingly used in dialysis and electrodialysis processes for the extraction, fractionation and concentration of valuable components, as well as reagent-free control of liquid media pH in the food industry. Fouling of IEMs is specific compared to that observed in the case of reverse or direct osmosis, ultrafiltration, microfiltration, and other membrane processes. This specificity is determined by the high concentration of fixed groups in IEMs, as well as by the phenomena inherent only in electromembrane processes, i.e., induced by an electric field. This review analyzes modern scientific publications on the effect of foulants (mainly typical for the dairy, wine and fruit juice industries) on the structural, transport, mass transfer, and electrochemical characteristics of cation-exchange and anion-exchange membranes. The relationship between the nature of the foulant and the structure, physicochemical, transport properties and behavior of ion-exchange membranes in an electric field is analyzed using experimental data (ion exchange capacity, water content, conductivity, diffusion permeability, limiting current density, water splitting, electroconvection, etc.) and modern mathematical models. The implications of traditional chemical cleaning are taken into account in this analysis and modern non-destructive membrane cleaning methods are discussed. Finally, challenges for the near future were identified.

Recovery of Nutrients from Residual Streams Using Ion-Exchange Membranes: Current State, Bottlenecks, Fundamentals and Innovations

“…Indeed, the nutrient recovery is carried out from liquids that contain a large number of microorganisms or organic and inorganic substances that are a nutritional medium. These substances are adsorbed by IEMs due to electrostatic, ion-dipole, dipole-dipole and other interactions [ 213 , 214 , 215 ]. In addition, concentration polarization and local changes in pH can lead to scaling of inorganic substances.…”

“…A detailed analysis of various fouling, scaling, biofouling mechanisms and the impact of these phenomena on the characteristics of IEM bulk and surface, as well as on their transport characteristics (conductivity, diffusion permeability, permselectivity) and on the phenomena accompanying concentration polarization (WS, electroconvection (EC), etc.) is made in recent reviews [ 64 , 80 , 213 , 214 , 217 ] and summarized in Figure 14 . Therefore, we will not analyze these phenomena in detail.…”

“…As already mentioned in Section 4.2 , the causes of membrane fouling are considered in sufficient detail in many original papers and reviews, for example, in [ 64 , 80 , 213 , 214 ]. Therefore, we will briefly dwell only on the more intense degradation of IEMs during their operation in solutions containing phosphoric acid and/or ammonium anions.…”

“… Schematic representation of the changes in the bulk and surface of IEMs caused by fouling and the effect of these changes on the most important characteristics of membrane processes in the applied electric field and in its absence. Reproduced from [ 214 ]. …”

Fouling and Mitigation Behavior of Foulants on Ion Exchange Membranes with Surface Property in Reverse Electrodialysis

“…Fouling is one of the most common problems in electrodialysis (ED) using ion exchange membranes (IEMs). In general, fouling is caused by the precipitation of foulants such as organics, colloids and biomass into IEMs and/or onto the surface of IEMs [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. The fouling causes a decrease in the transport flux of ions due to fouling complications of the membrane, an increase in the membrane resistance and a loss in selectivity and thus affects negatively membrane properties and performance [ 15 , 16 ].…”