Carbon molecular sieves from Nomex aramid fibres

摘要

Nomex-based activated carbon fibres (ACFs) have recently been suggested as promising precursors for carbon molecular sieves (CMSs) on the basis of their outstanding homogeneity in pore size. Taking advantage of this feature, microporous carbon molecular sieves for separating gaseous mixtures such as CO2/CH4 and O2/N2 (air separation) have been prepared through chemical vapour deposition (CVD) of benzene on ACFs obtained from Nomex aramid fibre. Two ACFs activated to different burn-off (BO) degrees were selected and CVD treatments were carried out on them during different periods of time. Whereas the evolution of adsorption capacity was investigated by immersion calorimetry into liquids of different molecular sizes (dichloromethane, benzene and cyclohexane), the progress of selectivity was followed by adsorption kinetic experiments. Carbon molecular sieves with good selectivity for the two studied separations and showing acceptable adsorption capacities were obtained from ACFs activated to the two chosen Bos.