Fouling and Membrane Degradation in Electromembrane and Baromembrane Processes

Abstract: This work provides an overview of the processes of fouling, the deposition of substances on the surface or in the pores of membranes, leading to deterioration of their performance. Degradation and fouling phenomena in various membrane materials, as well as the mechanisms of these processes, are considered. It is shown that, despite the difference in the chemical composition, morphology of membranes, ion exchangers, and the phenomena in which they are used, the phenomena leading to clogging of their surface and pores are largely similar. Among the main substances that contaminate membranes are organic molecules, polyelectrolytes, crystals of inorganic substances formed from ions contained in a solution, as well as colloidal particles, and biological organisms. The binding strength of foulants essentially depends on their nature and on the chemical composition of the membranes. At the same time, many fouling phenomena have their own characteristics. For example, in the processes of electricity generation in fuel cells or hydrogen production in electrolyzers, the formation of oxides or metal particles is observed in the membrane pores due to the electrolysis processes. The consequences of the processes of fouling and methods of their control are also considered. It should be noted that cleaning of membranes is still the main method of preventing fouling. At the same time, in recent years, research has been intensively developed in the field of inhibition of corrosion processes, as well as the creation of integrated approaches that integrate various processing processes, including both membrane and other technologies.