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As a first step of an ongoing study of thermodynamic properties and adsorption of complex fluids in confined media, we present a new theoretical description for spherical monomers using the Statistical Associating Fluid Theory for potential of Variable Range (SAFT-VR) and a Non-Local Density Functional Theory (NLDFT) with Weighted Density Approximations (WDA). The well-known Modified Fundamental Measure Theory is used to describe the inhomogeneous hard-sphere contribution as a reference for the monomer and two WDA approaches are developed for the dispersive terms from the high-temperature Barker and Henderson perturbation expansion. The first approach extends the dispersive contributions using the scalar and vector weighted densities introduced in the Fundamental Measure Theory (FMT) and the second one uses a coarse-grained (CG) approach with a unique weighted density. To test the accuracy of this new NLDFT/SAFT-VR coupling, the two versions of the theoretical model are compared with Grand Canonical Monte Carlo (GCMC) molecular simulations using the same molecular model. Only the version with the "CG" approach for the dispersive terms provides results in excellent agreement with GCMC calculations in a wide range of conditions while the "FMT" extension version gives a good representation solely at low pressures. Hence, the "CG" version of the theoretical model is used to reproduce methane adsorption isotherms in a Carbon Molecular Sieve and compared with experimental data after a characterization of the material. The whole results show an excellent agreement between modeling and experiments. Thus, through a complete and consistent comparison both with molecular simulations and with experimental data, the NLDFT/SAFT-VR theory has been validated for the description of monomers.

Experimental determinations versus pressure of the nonlinear acoustic parameter B/A have been conducted for methanol, 1-butanol and 1-octanol in the pressure range 0-50 MPa and temperature range 303.15-373.15 K. These measurements proceed from an experimental technique based on a phase comparison method allowing to measure the change in sound speed with the pressure for an isentropic process. The value of B/A is found to decrease with increasing pressure and seems to be an increasing function of temperature. A comparison with the data determined numerically by the classical thermodynamic method has also been performed.

Background The increasing awareness of the release of fluorinated gases (F‐gases) into the atmosphere is instigating the development of techniques to capture them from refrigerants. In this work, the adsorption of difluoromethane (R‐32), pentafluoroethane (R‐125), and 1,1,1,2‐tetrafluoroethane (R‐134a) on four different activated carbons (ACs) is studied. Additionally, the selectivity of the ACs for the components of commercial refrigerants, R‐410A and R‐407F, is evaluated. Results The estimation of the density of the adsorbed phase as a function of temperature allows the experimental fractional loading of each F‐gas on any of the ACs to be correlated as a temperature‐independent function of its reduced pressure, which is described by Tóth or dual‐site Langmuir equations or as an exponential function of the adsorption potential under the framework of the Adsorption Potential theory (APT). It is shown that the APT can be generalized with excellent accuracy to the systems studied if an adsorbate‐dependent affinity coefficient is used as a shifting factor to bring the characteristic curves of all F‐gases into a single one for each AC. R‐32 is the F‐gas most adsorbed by all adsorbents, followed by R‐134a, and by R‐125. All ACs are selective for R‐125 in R‐410A commercial refrigerants, especially at lower pressures. Additionally, all ACs are selective for R‐125 and R‐134a over R‐32 in R407‐F commercial refrigerant. Conclusion The utilization of ACs for adsorption of the three most used F‐gases is promising. By selecting ACs with different porous characteristics, it is possible to evaluate their influence on the selectivity for the components of different commercial refrigerants. © 2020 Society of Chemical Industry

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An experimental apparatus was developed to measure, over a wide range of pressure, the acoustical nonlinear parameter B/A with an uncertainty of 2.2% in order to study the influence of pressure on the value of this parameter in liquids. The experimental technique rests on an improved thermodynamic method which uses a highly sensitive phase comparison technique to measure the change in speed of sound with pressure. The apparatus was then used to measure B/A in water within the pressure range from 0.1 to 50 MPa and at temperatures of between 303.15 and 373.15 K. The data obtained were compared with those in the literature which come from numerical derivation of speed of sound measurements.