Analysis of Adsorbate-Adsorbate and Adsorbate-Adsorbent Interactions to Decode Isosteric Heats of Gas Adsorption

作者：Madani S Hadi; Sedghi Saeid; Biggs Mark J; Pendleton Phillip^*

来源：ChemPhysChem, 2015, 16(18): 3797-3805.

DOI：10.1002/cphc.201500881

• condensation heat
• gas adsorption
• isosteric heat of adsorption
• non-specific interactions
• specific interactions

A qualitative interpretation is proposed to interpret isosteric heats of adsorption by considering contributions from three general classes of interaction energy: fluid-fluid heat, fluid-solid heat, and fluidhigh-energy site (HES) heat. Multiple temperature adsorption isotherms are defined for nitrogen, T=(75, 77, 79)K, argon at T=(85, 87, 89)K, and for water and methanol at T=(278, 288, 298)K on a well-characterized polymer-based, activated carbon. Nitrogen and argon are subjected to isosteric heat analyses; their zero filling isosteric heats of adsorption are consistent with slit-pore, adsorption energy enhancement modelling. Water adsorbs entirely via specific interactions, offering decreasing isosteric heat at low pore filling followed by a constant heat slightly in excess of water condensation enthalpy, demonstrating the effects of micropores. Methanol offers both specific adsorption via the alcohol group and non-specific interactions via its methyl group; the isosteric heat increases at low pore filling, indicating the predominance of non-specific interactions.

• 出版日期2015-12-21