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Membranes 2019, 9(1), 8;

Modelling Mixed-Gas Sorption in Glassy Polymers for CO2 Removal: A Sensitivity Analysis of the Dual Mode Sorption Model

Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, 40131, Bologna, Italy
Author to whom correspondence should be addressed.
Received: 31 October 2018 / Revised: 29 November 2018 / Accepted: 20 December 2018 / Published: 4 January 2019
(This article belongs to the Special Issue Gas Transport in Glassy Polymers)
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In an effort to reduce the experimental tests required to characterize the mixed-gas solubility and solubility-selectivity of materials for membrane separation processes, there is a need for reliable models which involve a minimum number of adjustable parameters. In this work, the ability of the Dual Mode Sorption (DMS) model to represent the sorption of CO2/CH4 mixtures in three high free volume glassy polymers, poly(trimethylsilyl propyne) (PTMSP), the first reported polymer of intrinsic microporosity (PIM-1) and tetrazole-modified PIM-1 (TZ-PIM), was tested. The sorption of gas mixtures in these materials suitable for CO2 separation has been characterized experimentally in previous works, which showed that these systems exhibit rather marked deviations from the ideal pure-gas behavior, especially due to competitive effects. The accuracy of the DMS model in representing the non-idealities that arise during mixed-gas sorption was assessed in a wide range of temperatures, pressures and compositions, by comparing with the experimental results available. Using the parameters obtained from the best fit of pure-gas sorption isotherms, the agreement between the mixed-gas calculations and the experimental data varied greatly in the different cases inspected, especially in the case of CH4 absorbed in mixed-gas conditions. A sensitivity analysis revealed that pure-gas data can be represented with the same accuracy by several different parameter sets, which, however, yield markedly different mixed-gas predictions, that, in some cases, agree with the experimental data only qualitatively. However, the multicomponent calculations with the DMS model yield more reliable results than the use of pure-gas data in the estimation of the solubility-selectivity of the material. View Full-Text
Keywords: dual mode sorption model; mixed-gas sorption; PIMs; glassy polymers dual mode sorption model; mixed-gas sorption; PIMs; glassy polymers

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Ricci, E.; De Angelis, M.G. Modelling Mixed-Gas Sorption in Glassy Polymers for CO2 Removal: A Sensitivity Analysis of the Dual Mode Sorption Model. Membranes 2019, 9, 8.

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