ADSORBENT CARBON SYNTHESIS FROM COALS BY PHOSPHORIC-ACID ACTIVATION

The chemical activation of a bituminous coal by reaction with phosphoric acid has been followed by studying chemical and structural changes to the activate and the development of porosity. There are clear differences in porosity development after thermal treatment in the range 350-650-degrees-C and after heat treatment in the same temperature range following reaction with phosphoric acid. It is proposed that chemical treatment causes rupture of weaker linkages in the coal structure and early development of a rigidly cross-linked product through the formation of new stronger linkages. This process is accompanied by development of a mainly microporous structure which reaches a maximum BET surface area of approximately 750 M2g-1 HTT approximately 550-degrees-C. Pore structure development can be tailored to some extent by varying both phosphoric acid strength and final heat-treatment temperature.