Investigation of various aerogels as adsorbents for methane storage

Abstract

Excess CH4 adsorption isotherms on silica aerogel (Sa), two resorcinol formaldehyde aerogels (RFas) and carbon aerogel (Ca) were measured in the temperature range of 298-318 K and pressures up to 12 MPa. absolute adsorption isotherms were calculated from experimental excess adsorption isotherms using pore volume of each adsorbent. RFa-17 had maximum absolute CH4 uptake of 22 mmol/g at 298 K and 10 MPa. adsorption isotherms for all aerogels were well represented with the Freundlich model in the pressure range of the experiments. Excess CH4 uptake was significantly affected by the micropore surface area in aerogels. the isosteric heat of adsorption for each aerogel was found to be dependent on the surface coverage. among all aerogels, RFa-10 had the highest heat of CH4 adsorption. adsorption capacities of aerogels were comparable with other classes of adsorbents, which calls for further investigations for development of aerogels as materials for methane storage.