A SIMPLE-MODEL AND EXPERIMENTS FOR ADSORPTION-DESORPTION HYSTERESIS -WATER-VAPOR ON SILICA-GEL

A simple model is proposed for the evaluation of the primary and secon dary adsorption and desorption processes for hysteresis-dependent sorp tion systems. The model is based on the use of pore blocking interpret ation of hysteresis in an interconnected network of pores. The model i s simple to use and requires only the primary adsorption and primary d esorption isotherms to predict all secondary desorption and adsorption isotherms. A complete set of equilibrium adsorption-desorption curves covering the hysteresis loop (appearing in the range of relative pres sure 0.3-0.7) was measured for water vapor on silica gel at 25-degrees -C. The usefulness of the model is supported by its agreement with exp erimental data.