Adsorption of gas mixtures in compliant activated carbons

V. CORNETTE; J.C.A DE OLIVEIRA; R.H. LÓPEZ; C.L. CALVALCANTE; D.C.S ACEVEDO; G. ZGRABLICH

Paris

Workshop; Workshop on Adsorption in Compliant Solids; 2011

In this work, we use to study adsorption-induced deformation of CO2-CH4 mixtures. A simple yet instructive thermodynamic model of the adsorption stress, which was successfully employed in the previous works on adsorption deformation of microporous solids like zeolites,4 active carbons,3 and MOFs.5The proposed model relates the stress, exerted by the adsorbed phase on the adsorbent framework, with the adsorption isotherm. From the thermodynamic standpoint, the adsorption stress σs can be quantified by the derivative of the grand thermodynamic potential Ω of the adsorbed phase with respect to the pore volume V at fixed temperature T and P 4.Let us consider a single slit-shaped pore of width H between two graphite planar walls stabilized by some internal elastic elements. This model was considered in recent papers.6,7 The stiffness of the internal elastic elements is characterized by an effective elastic modulus k. During adsorption, the elastic elements can be either stretched or compressed causing an incremental change of the pore width, ΔH.