title: A comparison of supercritical carbon dioxide and organic solvents for the intercalation of 4-phenylazoaniline into a pillared clay mineral.
abstract: The intercalation of 4-phenylazoaniline (PAA) in supercritical carbon dioxide (SC-CO(2)) into montmorillonite (TMA-Mnt) pillared with tetramethylammonium ions at 313 K and 15 MPa was investigated. The adsorption rate and equilibrium PAA uptake were compared with those in n-hexane, CCl(4) and benzene solutions at 313 K. The XRD and N(2) adsorption/desorption analyses showed that TMA-Mnt after adsorption of PAA in SC-CO(2) had the same pore structure as after adsorption of PAA in normal solvents. SC-CO(2) was found to be a good medium for PAA adsorption owing to its having a relatively high adsorption rate and the highest adsorptivity at the same PAA concentration. The properties of PAA adsorption on TMA-Mnt could be well elucidated by the difference in solubility parameters between liquid and solid phases.
authors.affiliation: Institute for Marine Resources and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 2217-14, Hayashi-cho, Takamatsu, Kagawa, 761-0395, Japan. ryo-ishii@aist.go.jp
authors.forename: Ryo
authors.initials: R
authors.lastname: Ishii
authors.forename: Hideo
authors.initials: H
authors.lastname: Wada
authors.forename: Kenta
authors.initials: K
authors.lastname: Ooi