Solubility and diffusivity of H2 and CO2 in the ionic liquid [bmim][PF6]

We report on the measurement of the solubility and diffusivity of H-2 and CO2 in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) over the temperature range 25 degrees C-55 degrees C and for pressures of up to 10 MPa. The data were obtained using a magnetic suspension balance, a gravimetric instrument that is capable of simultaneously and accurately measuring the gas solubility and diffusivity in such liquids. To our knowledge, this is the first time that the H-2 diffusivity has been measured in an ionic liquid. While solubility data for H-2 have been previously reported, they vary widely. The cause for such variations is discussed as well. The diffusivity data for both H-2 and CO2 follow an Arrhenius-like dependence on temperature. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.