DEVELOPMENT OF MICROPOROSITY IN CARBONS DERIVED FROM ALKALI DIGESTED COAL

A series of high surface area carbons were produced from a brown coal digestion with KOH and NaOH followed by carbonisation. High resolution nitrogen adsorption isotherms determined over the relative pressure r ange 10(-6) to 1 at 77 K of these carbons revealed that the pore sizes in the micropore and mesopore regions can be controlled by changing t he stoichiometric ratio of alkali to oxygen functionalities of coal. C omparison of micropore surface areas determined from nitrogen at 77 K and carbon dioxide at 273 K showed that complete exchange of carboxyl groups with K+ facilitates nitrogen accessibility to entire micropore space. (C) 1998 Elsevier Science Ltd. All rights reserved.