Stoeckli, Fritz

1995, Stoeckli, Fritz, Centeno, Teresa A., Donnet, Jean-Baptiste, Pusset, Nadia, Papirer, Eugéne

The results obtained from a variety of techniques (vapour adsorption, selective adsorption of caffeine and immersion calorimetry) used to characterize activated carbons of industrial origin are compared. It is shown that gate effects due to constrictions, and often overlooked, can be revealed by simple experiments with larger molecular probles. Immersion calorimetry appears to be a simple and efficient technique, as illustrated by an activation series. Complementary information is also provided by scanning tunnelling microscopy (STM).

1994, Lebgaa, Dénia, Ehrburger, Pierre, Papirer, Eugène, Donnet, Jean-Baptiste, Stoeckli, Fritz

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.

1994, Donnet, Jean-Baptiste, Papirer, Eugène, Wang, W., Stoeckli, Fritz