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Supercritical CO 2 extraction of organic contaminants from aqueous streams
Author(s) -
Ghonasgi D.,
Gupta S.,
Dooley K. M.,
Knopf F. C.
Publication year - 1991
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690370617
Subject(s) - supercritical fluid , chemistry , mole fraction , supercritical fluid extraction , solubility , aqueous solution , partition coefficient , extraction (chemistry) , phenol , benzene , aqueous two phase system , chromatography , thermodynamics , organic chemistry , physics
Supercritical fluid extraction (SCFE) for the removal of organic toxins from water has been studied using a continuous‐flow view cell system. Distribution coefficients (ratio of mole fraction of contaminant in supercritical CO 2 to mole fraction in the aqueous phase at equilibrium) have been determined for a homologous series of contaminants as individual components in pure water: benzene, phenol, p‐chlorophenol, and m‐cresol. Data were obtained at two temperatures (313 and 323 K) and over a pressure range of 9.65 to 17.23 MPa for each contaminant. The distribution coefficients of the contaminants follow a pattern that can be explained in terms of molecular interactions both with water in the aqueous phase (as quantified by the pure contaminant solubility in water) and with CO 2 in the SCF phase (as quantified by the pure contaminant solubility in near‐critical CO 2 and crossover phenomena in SCF CO 2 ). These results have been accurately modeled using a hardsphere, perturbation‐theory‐based Carnahan‐Starling‐DeSantis‐Redlich‐Kwong equation of state and simple van der Waals mixing rules.