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

Gas adsorption microcalorimetry and modelling to characterise zeolites and related materials

“…The relationship between these two quantities can be given by n a = n r + c·v a , where n a is the absolute amount adsorbed, n r the excess amount adsorbed, c the concentration of adsorbate in the gas phase and v a the volume of the adsorbed phase. In the case of zeolites it is possible to consider the total pore volume for v a [37,38]. This total pore volume was obtained from the t-plots of the isotherms obtained at 77 K. The difference in 'absolute' and 'excess' amounts adsorbed is generally within magnitude of less than 1% for the adsorption at 77 K on microporous solids and in the present case, this difference is about 0.2%.…”

Do the Differential Enthalpies of Adsorption Vary Between 77 K and 302 K? An Experimental Case Study of Argon and Nitrogen on Two Faujasite Type Zeolites

“…The relationship between these two quantities can be given by n a = n σ + c.v a , where n a is the absolute amount adsorbed, n σ the excess amount adsorbed, c the concentration of adsorbate in the gas phase and v a the volume of the adsorbed phase. In the case of zeolites it is possible to consider the total pore volume for v a (Neimark and Ravikovitch, 1997;Pribylov et al, 1991). This total pore volume was obtained from the t-plots of the isotherms obtained at 77 K. The difference in "absolute" and "excess" amounts adsorbed is generally within magnitude of less than 1% for the adsorption at 77 K on microporous solids and in the present case, this difference is about 0.2%.…”

Methane adsorption on various adsorbents and the possibility of its storage in the adsorbed state

“…It should be noted that the isotherm approaches the abscissa axis asymptotically at pressures above 130 MPa. This behavior of excess adsorption iso therms is characteristic of adsorption systems with adsorbents having a rigid structure of the synthetic zeolite NaA type (a crystalline alumosilicate) [4]. Car bon adsorbent could thus with some certainty be assigned to the class of adsorbents with a rigid structure.…”