S. Galier et H. Roux-de Balmann, Study of the mass transfer phenomena involved in an electrophoretic membrane contactor, J MEMBR SCI, 194(1), 2001, pp. 117-133
Electrophoretic separators, in which a porous membrane is used as a contact
or, offer the possibility to scale up electrophoresis as well as to extend
the field of application of electrodialysis to fractionate polyamino acids,
peptides or small proteins for instance. This paper deals with the study o
f the mass transfer mechanisms involved in such electroseparation processes
. On one hand, a theoretical approach is carried out. The different contrib
utions to the mass transfer are considered in order to establish a relation
ship providing the solute concentration as function of the main parameters
of the system, i.e. the operating conditions and the membrane, buffer and s
olute characteristics. In this expression, a partition coefficient is used
to represent the interactions taking place at the membrane-solution interfa
ce. Then, an experimental study is performed with different representative
solutes using a prototype apparatus in order to determine the dependence of
the solvent and solute transfer with respect to the operating and physicoc
hemical parameters of the system. The experimental results show the existen
ce of a limiting electro-osmotic flux, the origin of which is explained. Th
en the partition coefficient is determined for any set of conditions by fit
ting the variations of the solute concentration calculated by the model wit
h experimental ones. The dependence of the partition coefficient with respe
ct to the solute and buffer characteristics, together with that of the tran
smission coefficient obtained during filtration experiments, shows that the
main limitation with respect to the mass transfer is due to electrostatic
interactions taking place at the membrane-solution interface. (C) 2001 Else
vier Science B.V. All rights reserved.