Adsorption of methane into ZnCl2-activated carbon derived discs

Abstract Binderless activated carbon discs for methane adsorption have been prepared by impregnation of olive stones with solutions of ZnCl 2 , compacting under pressure at 150 and 300 °C and heat treatment at 500 °C under a flow of nitrogen. The porosity development along the activation process is expected for this precursor; activated carbons with a very small volume of meso- and macropores and a large volume of micropores are obtained when the impregnation ratio is intermediate, X Zn  = 0.30 g/g. Since compacting under pressure means a low interparticle space, the disc volume (above 1.2 cm 3 /g) is almost equally distributed between micropores and the carbon skeleton. The methane capacity at 3.4 MPa is in the range of 100 V/V. Two discs were further activated by reaction under a flow of carbon dioxide. Although such activation implies a decrease in the bulk density because there is an increase in interparticle space (specially when the original disc is very dense), there is a net increase in the volume of micropores, the methane capacity increasing around 10%.