Effects of zeolite addition on the manganese catalyzed decomposition of hydrogen peroxide

Manganese catalyzed decomposition of hydrogen peroxide in the presence of v arious zeolites was investigated at different pH values, Mn concentrations and zeolite : Mn ratios. Depending upon the level of these parameters the z eolites studied displayed both catalytic and inhibitive effects on the rate of decomposition. At a high pH (10.8) Mordenite 10A in a twofold excess on an ion-exchange capacity basis acted as an inhibitor whereas the other zeo lites had little or no effect on the reaction rate. At a lower pH (9.0) zeo lite A when added in large excess resulted in a remarkable inhibitive effec t whereas the same zeolite resulted in a promotion of the catalytic action of manganese at an intermediate pH (9.9). The complex catalytic nature of z eolite-peroxide-Mn systems is discussed.