Over the past decade, advances in material processing have shifted growing attention to application and engineering of nanostructured materials. Some nanomaterials, like carbon nanotubes, have revealed tremendous potential for a variety of applications. Due to their high theoretical surface area and their hollow interior, carbon nanotubes have generated significant interest as adsorbents for gas processing and storage technology. In this work, adsorption data for methane, ethane, ethylene, and hydrogen on single-walled carbon nanotubes (SWNTs) at different temperatures between 278-318 K was collected for both as-prepared and acid-treated samples. At room temperature, SWNT samples purified via nitric oxidation and annealing, have been found to adsorb 4.7 wt. % methane and 0.31 wt. % hydrogen. For ethane and ethylene, experimental data shows preferential adsorption affinity for ethane occurs due to capillary condensation at conditions not seen for ethylene. In order to further improve gas storage of SWNTs, we have performed adsorption on pelletized as-prepared SWNTs samples. The effects of pelletization of adsorbent material on their adsorption of high-energy fuels, like hydrogen and methane, have been discussed. Overall, these strategies, with respect to meeting DOE targets for hydrogen and methane storage, were not successful at our experimental conditions. Further aspects, therefore, need to be considered to improve gas storage at ambient conditions.
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