Activated carbons with molecular sieve propeties

Carbon molecular sieves with micropore diameters of 0.41-0.54 nm were obtained by activation with water vapour to 6% burn-off of chars from oxidized bituminous coals and semianthracite. A temperature of 750 degrees C and a flow rate of 100 mL.min(-1) of N(2) with a 12.4% of steam content were used. Less developed microporosity was obtained from anthracite, that needed a 12% burn-off in order to obtain similar micropore development and size distribution. Activation temperature has an important influence in the development of microporosity of chars from anthracite. For chars from lo tv rank coals narrower micropore size distributions can be obtained by using in the activation a low stream flow rate.