It is theoretically predicted that when a solution of a low-molecular salt flows through a polyelectrolyte grid, electromotive forces can occur, the sign of which depends on the sign of the grid charge. This phenomenon can be used in the development of new desalination systems, but its further study requires the development of specific measuring instruments and experimental research methods. Such techniques can be created due to the fact that systems based on hydrogels of the type in question have equivalent radio engineering circuits, which include reactive components (capacitors). The presence of capacitors in the equivalent circuit is associated with the formation of double electrical layers at the boundary of the hydrogel and the solution. For grids with a high charge density, the amplitude of such layers can be determined directly based on the analysis of the balance of ion currents in the system. The capacitance of the capacitors included in the equivalent circuit can be measured by recording the phase shift between current and voltage as a function of frequency. This, in turn, allows us to develop a methodology for experimental research of systems of the type under consideration using probing alternating currents of small amplitude (the method of radio-technical sounding).
Keywords: radio engineering sensing, equivalent circuits, potential difference, polyelectrolyte hydrogels, water demineralization, double electric layer, induced electromotive force.
