Comparison of the volume charge density of nanofiltration membranes obtained from retention and conductivity experiments.
A version of the Donnan steric-partitioning pore model with dielectrical exclusion (DSPM-DE) has been used to get information on the pore size and charge density of a commercial membrane, NF45 from FilmTec, from its retention of KCl solutions. The conductivity inside the pores has been measured by impedance spectroscopy, and the electric potential drop during retention experiments has also been measured. These experimental data on conductivity and electric potential are analyzed, by using the thermodynamics of irreversible processes and the space charge model, to obtain the pore charge density of the membrane. These two methods give results in fair accordance which probes that the sometimes controversial method of DSPM-DE can give accurate results for the charge as well as for the mean pore size of a nanofiltration membrane. Some clues to improve the way this model can be used are given as well.
Benavente
Juana
J
Dpto. Física Aplicada, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain.
Silva
Verónica
V
Prádanos
Pedro
P
Palacio
Laura
L
Hernández
Antonio
A
Jonson
Gunnar
G