Low Pressure Methane Storage in Pinecone-Derived Activated Carbons

The methane adsorption properties of activated carbon samples from pinecones using chemical activation with different KOH/precursor ratio were estimated at room temperature (?298 K) and pressure up to 35 bar using a volumetric Sievert-type apparatus. A complete and detailed characterization of the synthesized activated carbon samples was obtained using nitrogen adsorption/desorption measurements at liquid nitrogen temperature (77 K), for the textural properties analysis, by scanning electron microscopy and X-ray diffraction for topography and long-range order estimation, and by wavelenght-dispersive spectrometry for chemical composition, respectively. All the adsorption data were analyzed by the Tóth isotherm model. The probed activated carbon samples show both higher methane storage values for pressures up to 35 bar (the maximum value reached is 15 wt%) and totally reversible methane uptake up to many cycles without any treatment in between indication of very stable properties. The experimental work reported in this paper could represent a good alternative method to the natural gas storage through the use of eco-compatible nanostructured materials.