ADSORPTION OF GASES ON CARBON MOLECULAR-SIEVES

Adsorption on carbon molecular sieves (CMS) prepared by coke depositio n has become an interesting area of adsorption due to its microporous nature and favorable separation factor on size and shape selectivity b asis for many gaseous systems. In the present work CMS was synthesized from coconut shell through three major steps, namely, carbonization, activation, and coke deposition by hydrocarbon cracking. The crushed, washed, and sieved granules of coconut shell (particle size 2-3 mm) we re pretreated with sodium silicate solution and oven-dried at 150 degr ees C to create the inorganic sites necessary for coke deposition. Car bonization and activation of the dried granules were carried out at 80 0 degrees C, for 30 min each. The activated char thus produced was sub jected to hydrocarbon cracking at 600 degrees C for periods varying fr om 30 to 180 min. The product samples were characterized in terms of a dsorption isotherm, kinetic adsorption curve, surface area, pore volum e, pore size distribution, and characteristic energy of adsorption by using O-2, N-2, C2H2, CO2, C3H6, and CH4. (C) 1994 Academic Press, Inc .