Papers by Keyword: Carbon Molecular Sieves

Abstract: Different compositions of carbon molecular sieve (CMS) were incorporated in polyethersulfone (PES) matrix to fabricate mixed matrix membranes (MMMs) by solution casting method. The characterization was carried out using field emission scanning electron microscopy (FESEM) analysis to investigate the morphology of membrane. FESEM images showed acceptable contacts between the filler particles and the polymer chains. The performance of the developed membrane is analyzed by single gas permeation measurement of high purity CO₂ and CH₄. Both CO₂ permeance and CO₂/CH₄ selectivity increased with CMS loadings as compared to pure PES membrane. Experimental results showed that the highest value of CO₂ permeance (66.71 GPU) and CO₂/CH₄ selectivity (10.94) can be achieved with 30 wt. % loading of CMS particles. This can be credited to size discrimination of CMS pores that falls between CO₂ and CH₄ kinetic diameters.

Abstract: A carbon molecular sieve for the purification of a gas mixtures containing O2, N2 and CO2, CH4 was produced from a waste granulated PET by means of a single carbonisation step at 973 K. Activated carbon materials presenting good adsorption capacity and some selectivity for O2/N2 and CO2/CH4 were prepared from granulated PET and cork oak with pore mouth narrowing using CVD from benzene. The diffusion coefficients of O2, N2, CO2 and CH4 in these materials were calculated and are comparable to published values determined on Takeda 3A and on a carbon molecular sieve prepared from PET textile fibres by means of carbonisation and subsequent CVD with benzene. However, the selectivities were not quite as good as those given by Takeda 3A. However, taking into account that this is a first attempt at producing CMS from PET, the results are encouraging, and it is to be expected that further development of the experimental procedure will result in new materials with improved performance.

Abstract: Graphitic N-free and N-doped carbon molecular sieves were prepared using zeolite NaY as a template via one-step chemical vapor deposition method (CVD) with propylene and acetonitrile as N-free and N-doped carbon precursors, respectively. The morphology, structure and properties of the carbons prepared were characterized via XRD, SEM, TEM and adsorption measurements. A large proportion of pore volume is associated with micropores in the carbons prepared. A high hydrogen uptake capacity is observed.