Experimental characterization of cyclopentane adsorption/desorption in microporous activated carbons

In this work, the adsorption of cyclopentane (CP) is investigated and characterized on four activated carbons (ACs) of complementary textural properties by combining characterization (pore volume, pore and particle size distributions), adsorption/desorption isotherms of CP and adsorption enthalpy measurements. On the one hand, the adsorption/desorption isotherms measured with a magnetic suspension balance have shown that between nearly 30% to 50% of CP adsorbed at saturation remains trapped in the ACs even after prolonged evacuation under primary vacuum. On the other hand, calorimetric/manometric measurements have evidenced that high-energy adsorption occurs at the lowest CP-loadings. Gas porosimetry before and after CP adsorption/desorption has made it possible to identify that the pore size distribution is the key parameter that controls cyclopentane trapping and that micropores smaller than 1.1 nm are responsible for hardly-reversible CP adsorption. Coupling of TGA with gas porosimetry has shown that temperatures must be higher than 550 K to remove CP trapped in the ultramicroporosity. (c) 2020 The Author(s). Published by Elsevier Ltd.