T. A. Kuznetsova

Thermodynamics of adsorption on microporous adsorbents above critical temperatures

The possibility of describing the isotherms of adsorption on microporous adsorbents at supercritical temperatures using the Dubinin-Radushkevich, Dubinin-Astakhov, and Tolmachev-Aranovich equations, in which the adsorbtive saturated vapor pressures that serve as the standard pressures below critical temperatures are substituted for the standard pressures (Ps*) found by the linear extrapolation of the dependences of adsorbtive saturated vapor pressure on the inverse temperature to the supercritical region, is shown. The possibility of linear extrapolation is substantiated by the data of a numerical experiment.

Absolute adsorption isotherms of gases and vapors within the lattice model

It is shown that the system of equations describing excess adsorption isotherms of the components of binary solutions previously obtained on the basis of the Ono-Kondo lattice model can be transformed to describe the absolute adsorption isotherms on microporous adsorbents of individual adsorbates at temperatures above and below critical.

DFT modeling of the adsorption of benzene, methanol, and ethanol molecules in activated carbon nanopores

Changes in energetic and structural characteristics of benzene, methanol, and ethanol molecules at their adsorption in nanosize slit-like pores of active carbon are estimated in quantum chemical calculations in the density functional approximation. The most energetically favorable arrangement of benzene molecules is found to be that when the molecular planes are parallel to each other and to the nanopore walls. Alcohol molecules are predominantly arranged so that C-O and C-C bonds are nearly parallel to the nanopore walls, while O-H bond is directed toward the nearest wall. At the adsorption of two alcohol molecules, they form a hydrogen bond and their skeletons are also parallel to the nanopore wall.

Thermodynamics of adsorption of krypton, xenon, nitrogen, and oxygen on microporous active carbon at temperatures above critical values

It was shown earlier that adsorption isotherms on microporous adsorbents at temperatures above the critical values can be described using the Dubinin-Radushkevich and Tolmachev-Aranovich equations when saturated adsorptive vapor pressures used as standard pressures at temperatures below the critical values are replaced by standard pressures P*(T) found by linear extrapolation of dependences of the logarithm of the saturated adsorptive vapor pressure on the inverse temperature. This was confirmed using the example of description of experimental adsorption isotherms of krypton, xenon, oxygen, and nitrogen on microporous active carbons AUK at the temperatures above the critical value.

Thermodynamics of adsorption of methane and carbon dioxide on microporous adsorbents at temperatures above critical values

The earlier-shown possibility that the isotherms of adsorption on microporous adsorbents at temperatures above the critical values can be described with the Dubinin-Radushkevich and Tolmachev-Aranovich equations is confirmed by describing the experimental isotherms of adsorption of methane and carbon dioxide on microporous AUK and PAU-10 coals at temperatures above critical values; in the above-mentioned equations, the pressure of saturated adsorbate vapors used as a standard pressure at temperatures below critical values is substituted for the standard pressures (P*) that are determined through extrapolating the dependences of the logarithm of the saturation vapor pressure for the adsorptive on an inverse temperature over the supercritical temperature range.

A computer adsorption database

Equations used in a computer adsorption database to describe the experimental data for the adsorption of gases, vapors, and solutions over macro- and microporous adsorbents have been considered.

Thermodynamics of adsorption of light hydrocarbons on microporous active carbons at supercritical temperatures

Methods for describing adsorption isotherms and the thermodynamic characteristics of adsorption of methane, ethylene, propane, and butane on active carbons are considered in a wide range of temperatures below and above the critical ones.

Thermodynamics of methane adsorption on microporous adsorbents at supercritical temperatures

The methods of description of isotherms and thermodynamic characteristics of methane adsorption on active carbons PAU-10 and AUK in the broad temperature range below and above critical have been considered.

Temperature dependence of adsorption on microporous adsorbents

Different ways to theoretically calculate the temperature dependence of the adsorption isotherms of individual substances on activated charcoals in a wide range of temperatures below and above critical temperatures are examined.

Thermodynamics of methane adsorption on X type zeolites at supercritical temperatures

Methods describing isotherms and thermodynamic properties of methane adsorption on various cationic forms of X-type zeolite at temperatures above critical ones are considered.