An experimental setup (a membrane rotating disk electrode) is described. Combinations ionitepolyethylene applied in the production of membranes MK-40, MK-41, and MA-40 are used as compositions modeling commercial monopolar ionite membranes. The setup design allows one to separately measure the diffusion limitations on the let-in and let-out sides of membranes. The comparison of experimental polarization characteristics and theoretical dependences (plotted earlier) shows that a polarization characteristic is a net dependence for two processes of electromasstransfer. One process is associated with the diffusion limitations from the solution side. The other is attributed to the hydrolysis of fixed ionogenic groups of the membrane’s ionite and precedes the electrochemical stage of charge transfer across the membrane/electrolyte interface.