Estimation of the temperature effect on the adsorption capacities of zeolites

The variations occurring in the ‘so called’ monolayer or saturation capacities with respect to changes in adsorption temperature were investigated for silicalite. The equation, nm=fV1−D, relates the number of moles adsorbed to the molar volume of the adsorbate and the adsorption fractal dimension value of the zeolite. Any change occurring in the capacity not related to the change in the effective size of the adsorbate is expected to be represented by the constant f. No regular pattern in the variation of the f values with respect to temperature could be observed. For the cases investigated, it seems that the effect of any other factor originating from the change in temperature, besides the variation of the effective size of the adsorbate, on the capacity value is negligible. Estimating the temperature effect on the capacity, by taking the adsorption fractal dimension into account, seems to result in capacities that are more consistent with the experimental values, compared to using the conventional linear relationship between the capacity and the temperature dependent liquid density or molar volume.