Anomalous Adsorption on Active Charcoal

Abstract

AT the recent discussion of the Faraday Society on the “Adsorption of Gases on Solids”, Prof. A. J. Allmand and his co-workers¹ presented a summary of their investigations on the discontinuities they have found in adsorption isotherms for gaseous adsorptions. They also referred to unpublished evidence, obtained by Chaplin, for the discontinuous adsorption of phenol from aqueous solutions on an active technical charcoal. This statement apparently refers to an investigation the details of which have now been published.² Of the three isothermals obtained, Chaplin prefers to place reliance upon the third one, the other two being inaccurate for the reasons discussed by the author himself. Chaplin has drawn an isothermal curve through the experimental points which exhibits marked discontinuities. It appears, however, that the curve has been drawn in an arbitrary manner, and a smooth adsorption isotherm can be obtained within the experimental error, only one point being markedly off the curve.