Porous carbon materials from brown coals

Low-metamorphosed brown coals are a relatively cheap and affordable source of raw materials to produce porous carbon materials. For this purpose, the methods of alkaline brown coal activation are widely used, which make it possible to obtain porous carbon materials with a well-developed microporous structure. Such porous carbon materials can exhibit high selectivity to the sorption of low molecular weight gases, which makes it possible to use them in gas separation processes.

The developed specific surface area and porosity of carbon materials obtained from brown coals determine their high sorption activity, in particular, hydrogen. It has been found that an increase in the specific surface area, pore volume, and average pore size of porous carbon materials obtained from brown coal leads to an increase in the sorption capacity over hydrogen. As the specific surface area and total pore volume increase, the sorption capacity of hydrogen increases. The maximum value (2.99% by weight) was obtained for the brown coals used at a coal / KOH ratio of 1:5.