Modified Expression of Dubinin-Radushkevich Equation Based on Adsorption and Desorption Tests of Activated Carbon

Abstract:

Previous studies showed that Dubinin-Radushkevich equation (D-R equation) does not describe the microporous adsorption well in the partial region of 2.59<［ln(p0/P)］2<10 (P is the balance pressure of adsorbate, p0 is the saturated vapor pressure at the experiment temperature). A modified expression of D-R equation is proposed herein for activated carbon materials in the range of 2.59<［ln(p0/P)］2<10. The adsorption capacity of the three activated carbon adsorbents at different relative pressures was tested with adsorption and desorption experiments, and the experimental data were fitted using proposed equations and original D-R equation. Results showed that in the range of 2.59<［ln(p0/P)］2<10, the proposed equations can describe microporous adsorption more accurately than the original D-R formula.

Key words:microporous adsorption; Dubinin-Radushkevich equation; activated carbon; adsorption and desorption tests