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.

中文翻译：

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三聚氰胺-间苯二酚-甲醛干凝胶中CO 2对CH 4，N 2和H 2的吸附选择性

据报道，三聚氰胺-间苯二酚-甲醛干凝胶对CO ₂，CH ₄，N ₂和H _2的吸附选择性，其中所有系统都表明从相应的二元气体混合物中选择性吸附CO _2的潜力。精选的混合气体代表了工业中重要的气体分离应用，即从电厂烟气中去除CO ₂（CO ₂ -N ₂），酸性气体脱硫（CO ₂ -CH ₄）以及水煤气变换中的物质分离反应（CO ₂ -H ₂）。所有测试的材料均表现出微孔特性，可增强小分子的吸附能力，但是，将富氮材料包含在凝胶基质中可提高这些系统的选择性。尽管凝胶具有多孔特性，但在用于模拟工业参数的测试条件下，所有三种平衡气体，即H ₂，N ₂和CH ₄，对干凝胶的亲和力均较低，而CO _2的吸附量则显着提高并随三聚氰胺的夹杂物和浓度增加。理想的吸附溶液理论被用来证明吸附吸收的显着差异，尤其是对于CO ₂ -CH ₄对N _2的CO ₂选择性高。在所有情况下，选定的干凝胶在竞争气体中均表现出与工业相关的CO ₂吸附时间标度，证明了这些材料从工艺流中选择性吸附CO ₂的潜力。