Activation chimique des charbons par les hydroxydes, carbonates et oxydes des métaux alcalins

Chemical activation of coals using aïkali metal hydroxides, oxides and carbonates. The preparation of active carbons is described, starting from two coals originating from Freyming and Oignies. Varions hydroxides, oxides and aïkali carbonates were used but the originality of this study is the use of cesium derivatives. The interpretation of the Coa adsorption isotherms shows clear differences among the various reagents. It is seen that CsOH is more efficient than KOH, and that Cs20 is even more active than CsOH. Furthermore, by mixing an inactive hydroxide (NaOH) with KOH, a new, more efficient, activating agent was obtained. Immersion calorimetry studies confirm the gas adsorption results. Finally, scanning electron microscopy and scanning tunnelling microscopy evidence the formation of porosity.