Optimizing CO2 and CH4 storage: The role of high skeletal density activated carbon in adsorption processes

An immediate strategy for reducing atmospheric emissions is the capture and storage of greenhouse gases. Among different approaches, a very promising one is the adsorption onto activated carbons. This study investigates how physicochemical features influence the carbon dioxide (CO2) and methane (CH4) adsorption capacities of a commercial activated carbon, the G-BAC-G70R produced by Kureha®, benchmarking its performance against conventional gas compression techniques. Morphological, chemical and textural characteristics were analyzed, while adsorption properties were assessed using a Sievert-type volumetric apparatus. The aim of this work is to demonstrate the material’s superior adsorption capacity under identical thermodynamic conditions compared to an empty tank. The results demonstrated that the high skeletal density (2.62 g/cc) and the porosity features play a key role in enhancing storage capacity. Experimental data reveal that G-BAC-G70R has a high specific surface area of 1312 m²/g with a predominant microporosity. Adsorption investigations, conducted at three temperatures (278 K, 298 K, and 328 K) and within pressure ranges of 0–50 bar for CH₄ and 0–15 bar for CO₂, highlighted complete reversibility and cyclicity of the process and a maximum storage capacity between 6 and 9 mol/L and 7–13 mol/L respectively. Finally, the isosteric heat of adsorption evaluation confirmed how, for both investigated gases, the interactions between adsorbent and adsorbate are purely physical with values around 13.7 kJ/mol and 22 kJ/mol for CH4 and CO2 respectively. The G-BAC-G70R appears to be a promising material for both CH4 storage and CO2 capture.