Use of a zeolite-modified electrode for the study of the methylviologen-sodium ion-exchange in zeolite Y

The electrochemical response of zeolite-modified carbon paste electrodes (Z MCPEs) has been exploited to plot the normalised ion-exchange isotherm of m ethylviologen and sodium in zeolite Y. Results observed from the proposed m ethodology agree well with those obtained using the conventional procedure. Selectivity was very high for the large organic divalent cation over sodiu m species. but the degree of exchange of methylviologen did not exceed 64%. Electrochemistry of ZMCPEs allows the in situ quantitative determination o f methylviologen in the zeolite phase, without significant modification in the solution-phase concentrations. so that the ion-exchange isotherm can be plotted very rapidly and without any other chemical analysis. (C) 1999 Els evier Science S.A. All rights reserved.