Adsorption properties of methyl sulfide and methyl disulfide on activated carbon, zeolite, and silicate, and their porous structure.

Abstract

Adsorption of methyl sulfide and methyl disulfide as the offensive odor substances was measured by a gravimetric method to elucidate the mechanism of their adsorption on activated carbon, zeolite, and silicate. The mechanism of adsorption was discussed on the basis of the application of Dubinin-Astakhov equation (W=W0exp (-[A/E)n)] to the adsorption isotherms and the pore size distribution in the range of pore radius 7.5 to 300 Å. Dubinin-Astakhov equation was well applicable to the adsorption isotherm on activated carbon and the exponent n was 2. No straight line was found between log W and An (n=1-6) of adsorption isotherm on zeolite. A plot of log W against A (n=1) of adsorption isotherm on silica gel was found to be linear. It was confirmed that the adsorption of methyl sulfide and methyl disulfide on activated carbon and silica gel resulted in the volume filling of their micropores by the mechanism of capillary condensation, and that its adsorption was a physical adsorption. The amount of methyl sulfide and methyl disulfide adsorbed on the porous adsorbents was determined by their micropore volume of pore radius less than about 20 Å.