Equilibrium exchange isotherms were determined for the exchange of Cu2
+ with NaZSM-5 at varying Cu(Ac)2 concentrations in solutions of const
ant volume and zeolite weight. At low Cu2+ levels the solid scavenged
all the copper ions. When copper could be detected in the equilibrated
solutions, ''overexchange'' was observed. The extent of ''overexchang
e'' was higher at pH almost-equal-to 6 than at pH almost-equal-to 4. T
hese results were analyzed in relation to catalytic activity.