A new apparatus for the determination of adsorption isotherms and adsorption enthalpies on microporous and meso-porous media

A specific thermostated experimental device comprising a differential heat flow calorimeter coupled with a home built manometric system has been built for the simultaneous determination of adsorption isotherms and adsorption enthalpies. The differential heat flow calorimeter is a Tian Calvet Setaram C80 model which measures the heat flux of a gas and can be operated isothermally, the manometric system is a stainless steel homemade apparatus. This coupled apparatus allows measurements for pressure up to 2.5 MPa and temperature up to 423.15 K. On the one hand, the apparatus and the experimental procedures are described. On the second hand the reliability and reproducibility were established by measuring adsorption isotherms on a benchmark (Filtrasorb F400) at 318.15 K. The gravimetric method has been used at higher pressure at various temperatures. These devices allowed us to study the adsorption of supercritical fluid (nitrogen N2, methane CH4, carbon dioxide CO2) in activated carbons and microporous or meso-porous silica. The adsorption of methane on a rock of type (TGR) was also studied. These experimental results are used for the study of the interactions fluid / solid that must be taken into account in molecular simulations or DFT theory. (author)