Tailoring Porosity Development in Monolithic Adsorbents Made of KOH-Activated Pitch Coke and Furfuryl Alcohol Binder for Methane Storage

Abstract

A series of microporous carbon powders of Brunauer−Emmett−Teller (BET) surface area ranging from 1900 to 2700 m2/g was made from pitch-derived semi-cokes by KOH activation at 750 °C. The powders were compacted into disk-shaped monoliths using a furfuryl-alcohol-based binder. Activation with CO2 was used to open an access to the microporosity that was blocked by the binder char. The porous texture of monoliths was characterized by the N2 adsorption at 77 K and mercury porosimetry, and the volumetric storage capacity and delivery V/V was determined from the methane uptake at 25 °C and 3.5 MPa. The results suggest that there is an optimum in porosity development of activated carbon powder and monolith burnoff from the point of view of the monolith performance in volumetric methane storage. The highest adsorption capacity and delivery V/V, which amount to 163 and 145, respectively, represents the monolith made of activated carbon of moderate porosity development (SBET ∼ 2200 m2 g−1) that was activated to the burnoff of about 10%.