Activated carbons with molecular sieve properties

Potential carbon molecular sieves were obtained from coals of different rank by controlled oxidation pretreatment followed by carbonization and activation with steam to low bum-off. Activation temperature is important in the development of microporosity of chars from anthracite. For chars from low rank coals, narrower micropore size distributions can be obtained by using low activating stream flow rates. Materials with molecular sieve properties and microporosity mainly distributed within the 4.1-5.4 Angstrom range were prepared by coal preoxidation, carbonization and slight activation, using a low stream flow rate and a temperature of 750 degrees C during the activation step.