Controlling Synthesis of Polymer-Derived Carbon Molecular Sieve and Its Performance for CO2/CH4 Separation

Abstract

Due to its specific micropore structure, carbon molecular sieve (CMS) can provide more selective properties than conventional activated carbon in adsorbing molecule from a gaseous mixture. In this research, preparation of CMS for CO₂/CH₄ separation has been developed by pyrolysis of specially synthesized polymeric resins as the precursor. This research was particularly focused on the development of precursor for the control of carbon microporosity to enhance the sieving properties. Precursor was synthesized through polymerization reaction of phenol with formaldehyde and p-tert-butyl phenol using acid catalyst in a batch reactor. Pyrolysis of the polymeric precursors was carried out in a retort at 450 - 850°C in flowing N₂ inert gas at flow rate of 100 mL/h for 1.5 hours. The resulting micropore size and surface area of the carbon were characterized using N₂-sorption analysis, whereas the carbon surface morphologies were observed using SEM. The carbons were further characterized for their uptake capacity and kinetic selectivity toward CO₂ and CH₄ gases. The results show that the porous carbon has suitable characteristic as sieving material for CO₂/CH₄ separation. In this work, CMS with kinetic selectivity (DCO₂/DCH₄) as high as 8, was produced.