Adsorption selectivity of CO2 over CH4, N2 and H2 in melamine-resorcinol-formaldehyde xerogels

Principe, Ivan A. and Fletcher, Ashleigh J. (2020) Adsorption selectivity of CO2 over CH4, N2 and H2 in melamine-resorcinol-formaldehyde xerogels. Adsorption, 26 (5). pp. 723-735. ISSN 0929-5607 (

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Sorptive selectivity of melamine-resorcinol-formaldehyde xerogels, towards CO2, CH4, N2 and H2, is reported, where all systems demonstrate potential for selective adsorption of CO2 from corresponding binary gas mixtures. Selected gas mixtures represent important gas separation applications found in industry, i.e. CO2 removal from power plant flue gases (CO2-N2), sour gas sweetening (CO2-CH4), and separation of species in the water-gas shift reaction (CO2-H2). All materials tested exhibit microporous character, enhancing adsorption of small molecules, however, it is the inclusion of a nitrogen-rich material into the gel matrix that results in enhanced selectivities for these systems. Despite the porous character of the gels, under the test conditions used to simulate industrial parameters, all three balance gases, i.e. H2, N2 and CH4, showed low affinities for the xerogels, while CO2 adsorption was notably higher and increased with the inclusion and increased concentration of melamine. Ideal Adsorbed Solution Theory was used to demonstrate significant differences in adsorption uptake, especially for CO2-CH4, and high selectivities for CO2 over N2. In all cases, selected xerogels exhibited industrially relevant adsorption timescales for CO2 over competitor gases, demonstrating the potential of these materials for the selective adsorption of CO2 from process streams.


Principe, Ivan A. ORCID logoORCID: and Fletcher, Ashleigh J. ORCID logoORCID:;