The effect of wetting on pore texture and methane storage ability of NaOH activated anthracite

The present work deals with the role of water commonly present in carbonaceous materials, or added to them, on the NaOH activation process. The preliminary wetting of an anthracite subsequently activated with NaOH in definite conditions (1 h at 730 °C, mass ratio NaOH/carbon = 3) and its consequence on the pore texture and resulting methane adsorption capacities are discussed. Water was added to a powder of anthracite according to wetting ratios water/carbon ranging from 0% to 30%. Significant effects on BET surface area, pore texture, packing density and corresponding methane storage capacity were evidenced. Among the investigated wetting ratios, an optimum of 20–25 wt.% of water added to the anthracite was found to lead to the highest adsorption properties for methane. An additional densification finally allowed reaching deliverable methane capacities higher than 150 V/V.