Biomethane storage in activated carbons: a grand canonical Monte Carlo simulation study

As a desirable alternative to conventional fossil fuels, the relatively low energy density and poor storage by the adsorbent materials negatively affect the widespread application of CH4. Thus, efficient and cost-effective adsorbent materials for CH4 storage are highly desired. Activated carbons (ACs) are such potential adsorbent materials because of the high efficiency and low price. In this study, the adsorption of CH4 in ACs was investigated using grand canonical Monte Carlo simulations as a potential adsorbent for this purpose. The factors influencing the adsorption behaviour of CH4 in ACs with different structural properties and surface chemistry were examined, taking different preparation conditions of ACs into account. Effect of the size of the basic structural unit, effect of graphitisable carbons, non-graphitisable carbons and disordered carbons, the surface area of the ACs, the ordered pores in the ACs and the functional groups containing oxygen on CH4 storage were investigated. The simulation results showed that differences in pore size distributions had a stronger influence on CH4 performance. ACs with narrow pore size distributions and pores with sizes around 1.0 nm obtained higher CH4 capacity.