Adsorption of gases by microporous adsorbents under pressures up to hundreds megapascals

A volumetric-balance technique for measuring the equilibrium and kinetic adsorption parameters at elevated temperatures and under high pressures is described. Adsorption of nitrogen or crystalline zeolite of the 4A type was investigated within a temperature range of 300–600 K under pressures up to 160 MPa, and a new method for separate determination of the volumes and a and β zeolite voids was suggested. The total content isotherms were measured, and the isotherms of excess adsorption calculated. Using these data as the basis, corresponding adsorption isosteres were plotted and their runs analyzed. It has been shown that under pressures of about 150 MPa, the excess adsorption may become zero or even negative.