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Mass‐Transfer modeling in the pervaporation of VOCs from diluted solutions
Author(s) -
Urtiaga Ane,
Gorri Daniel,
Ortiz Inmaculada
Publication year - 2002
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.690480314
Subject(s) - pervaporation , mass transfer , chemistry , trichloroethylene , dichloromethane , membrane , polydimethylsiloxane , chromatography , thermal diffusivity , aqueous solution , mass transfer coefficient , permeation , chemical engineering , analytical chemistry (journal) , solvent , thermodynamics , organic chemistry , biochemistry , physics , engineering
A generic model is derived for studying the mass‐transfer kinetics of the pervaporation of multicomponent mixtures of volatile organochloride compounds. Applying it to the pervaporation of dilute mixtures of trichloromethane, dichloromethane and trichloroethylene using tubular polydimethylsiloxane (PDMS) membranes permits: (1) estimation of the representative mass‐transfer parameters, that is, solute diffusivity in the aqueous phase and membrane permeability of the individual components; (2) discrimination of the relative importance of the mass‐transport resistances to the pervaporation flux as a function of operation variables; and (3) determination of the selectivity in multicomponent pervaporation. Diffusivity values calculated with the model agree well with predictions by the Wilke–Chang correlation for nonelectrolyte solutes. Permeability values of PDMS membranes change in the trichloroethylene > trichloromethane > dichloromethane direction. The relative importance of mass‐transfer resistances for the considered volatile organic compounds depends on the operation variables, that is, flow rate of the feed solution and membrane thickness. Furthermore, for trichloroethylene the main resistance is located in the feed solution, whereas for dichloromethane for high values of feed flow rate the resistance in the membrane could exert a major influence on kinetic control, and the behavior of trichloromethane is intermediate between both compounds.