Preparation of Carbon Molecular Sieves from Pistachio Shell and Walnut Shell for Kinetic Separation of Carbon Monoxide, Hydrogen, and Methane

In this study, two Carbon Molecular Sieves using the Pistachio shell (CMS P) and Walnut shell (CMS W) were prepared by a chemical vapor deposition method and used for pressure swing adsorption and separation of CO/H2 and CO/CH4. The adsorption isotherms of gases obtained for both CMS’s. The Dubinin-Radushkevich isotherm model was used for comparing pore volume of CMS’s. The obtained isotherms for both CMS were compared with Langmuir and Freundlich isotherms. It was observed that Freundlich equation can better correlate the experimental data. The adsorption capacity of each CMS, and selectivity of them for separation of CO/H2 and CO/CH4 were obtained with the aid of kinetic studies. In comparison with CMS W, CMS P showed higher adsorption capacity values for gases, but lower selectivity for separation of them. Finally by fitting experimental data to a pseudo second-order equation, adsorption capacities at equilibrium were obtained for abovementioned gases on both CMS’s.