Adsorbate-adsorbate interactions on microporous materials

Simple isotherm models can fit microporous adsorption yet the molecular interactions underlying the successful fitting have often remained obscure. Here we demonstrate how semi-empirical isotherm model data can be mined to reveal the reality of adsorbate-adsorbate molecular interactions. This was made possible by the fluctuation adsorption theory, a rigorous theory based only on the principles of statistical thermodynamics. For microporous carbons, adsorbate-adsorbate interactions quantified from the Dubinin-Radishkevich (DR) and Dubinin-Astakhov (DA) models successfully capture the primary micropore filling mechanism and the subsequent layer adsorption, leading to a liquid-like behaviour of the adsorbates. The microscopic meanings of the DR and DA parameters and the adsorption potential have also been clarified via statistical thermodynamics.