OZONE TREATMENT OF COAL-BASED AND COFFEE GROUNDS-BASED ACTIVE CARBONS- WATER-VAPOR ADSORPTION AND SURFACE FRACTAL MICROPORES

Characteristics of the adsorption isotherms of water vapor on active c arbons from coal and coffee grounds and those ozonized ones from the s urface fractal dimension analysis are discussed. The upswing of the ad sorption isotherms in the low relative pressure of coffee grounds-base d active carbon, of which isotherms were not scarcely affected on ozon ization, was attributed to the adsorption of water molecules on the me tallic oxides playing the role of oxygen-surface complexes, which form ed the corrugated surfaces on the basal planes of micropore walls with the surface fractal dimension D-s > 2. On the other hand, coal-based active carbon with D-s < 2, which indicated the flat surfaces of micro pore walls, showed little effect on the upswing even on ozonization, e ven though the adsorption amounts of water vapor were increased in the low relative pressure, (C) 1998 Academic Press.