INCREASE OF ACID-SURFACE REACTIVITY THROUGH WATER-MOLECULES ADSORPTION PROCESS - V2O5-CACO3 BEHAVIOR

The increase in reactivity of crystalline V2O5 has been verified from its equimolecular mixture with calcite which was treated at 150-degree s-C in a saturated water-vapour atmosphere. Structural and phase chang es accompanying the reaction were followed by X-ray diffraction, infra red spectroscopy and scanning electron microscopy studies. The adsorpt ion of water molecules during the process as well as the reaction degr ee were quantitatively evaluated by thermal analysis. The results show ed the formation of calcium metavanadate as a final reaction product a nd strongly acid gels which were related to V2O5 as intermediate. The crystal-line initial V2O5 is decrystallized during the process of adso rbing water molecules with the formation of very acid reactive gels.