METHOD TO MEASURE THE NET HEAT OF ADSORPTION AND THE ADSORPTION-ISOTHERM SIMULTANEOUSLY

A new method is described to measure net differential heats of adsorption; it is applied to the adsorption of water vapour on active carbon and synthetic zeolite samples. The method seems equally appropriate for many other systems. By compensating the heat of adsorption instrumentally with the heat of condensation during an adsorption process, it is possible to measure directly the net differential heat of adsorption. Amounts adsorbed are also measured calorimetrically, while the pressure is registered simultaneously. The method may be operated in either a stepwise or a continuous dosing mode. A procedure is given to derive from the experimental data (adsorption isotherm and differential heat of adsorption) the differential entropy and energy of adsorption. © 1979.