Carbon molecular sieves (CMS) from coconut shell by carbonization and carbon dioxide activation

Abstract

Carbon Molecular Sieves (CMS) are specially treated micro porous adsorbents derived from carbonaceous precursors. Due to the molecular sieving property, coupled with thermal, mechanical and chemical stability under acidic/alkaline conditions, CMS have found many applications in the field of difficult gas, as well as liquid separations from their mixtures.

CMS have been successfully synthesized from a wide variety of carbonaceous materials, by the carbonization followed by carbon dioxide or steam activation. The effect of carbonization temperature and activation temperature on the surface area as well as pore volume, calculated using the carbon dioxide adsorption data at room temperature is studied. The most suitable

carbonization temperature is found to be in the range 750-850°C, beyond which the surface area is found to decrease due to sintering of the particles at high temperature. The samples prepared were found to give good adsorption selectivity for CO₂ over H₂ or N₂. Kinetic and equilibrium adsorption data for gases like N₂, O₂, H₂, CH₄, and equilibrium adsorption of

selected organic vapours are also reported.