Section III, 1921 ' [73] Traxs. R.S.C. 



The Thermal Evolution of Gases Absorbed by Charcoals and Carbonized . 



Lignites 



By Stuart McLean, M.A., University of Toronto 

 (Under Studentship from the Honorary Advisory Council for Scientific 

 and Industrial Research, Canada) 



Presented by E. F. Burton, F.R.C.S. 



(Read May Meeting, 1921) 



Early experiments on the absorption of gases by charcoal 

 showed that the phenomenon obeyed the following equation : 



where A'^ is the amount of gas absorbed per gram of charcoal at 

 temperature /, Pi is the pressure of the surrounding gas when equil- 

 ibrium is attained at temperature /, and A and n are constants for a 

 given temperature but are functions of the temperature. 



The above expression agrees very approximately with experi- 

 mental results over the range of ordinary pressures. 



If the pressure is kept constant and the temperature varied the 

 adsorption is represented according to Titoff^ by the equation 



log Xt = log A'o - (a~b\og P).t. 

 where Xi and A'^ are values of X at temperatures / and 0°C, 



a equals (log A) and b equals ( — I . 



dt dt \ n / 



Several theories have been put forward to account for the process 

 of adsorption : 



(1) Chemical Combination. — In order to explain the production 

 of the large amount of heat during adsorption it was suggested that 

 chemical combination takes place, with the consequent production of 

 carbon monoxide and dioxide. 



(2) Solid Solution. — This theory which contemplates the actual 

 penetration of the gas into the charcoal, the concentration being 

 constant throughout the whole mass of the charcoal, was accepted 

 by Miss Homfray- as being most consistent with her results. 



iTitoff: Zs. f. phys. Chem. 74, 1910, p. 641. 



• Miss Homfray: Zs. f. phys. Chem. 74, 1910, p. 641. 



