Аннтотация
© 2020 Elsevier B.V. Modern trends in improving the technology of production of ion exchange membranes consist in the search for possibilities of obtaining thin or ultra-thin samples. They allow to minimize the mechanical resistance to transport in electrodialysis, increase the driving force of the process, help to create more compact electromembrane devices, they are preferred in devices that use the salinity gradient and membrane potential in generating electricity, as well as they allow to save on ion exchange material, which makes such membranes more profitable compared to standard commercially available analogues. In this study аn experimental batch of heterogeneous ion exchange membranes MK-40 and MA-41, having a thickness in the swollen state of 0.26–0.44 mm, was studied. The electrical conductivity of the membranes, diffusion permeability, and their behavior in electrodialysis were considered. Electrodialysis of NH4NO3 solution (0.012 mol∙dm−3) was carried out using 0.28 mm thick membranes. It has been established that a decrease in the membrane thickness results in higher values of the limiting current density and a longer plateau of the limiting current on the experimental current-voltage curve of the membrane. These peculiarities are connected with an increase in the reverse diffusion flow of the electrolyte from the concentrating compartments and a stronger development of electroconvection. A lesser degree of alkalization of the solution in the concentrating compartments is also observed when thinner ion exchange membranes are used.