NAMS 2002 Workshop - ICOM 2008

Ultra- and Microfiltration III - Membranes – 6
Friday July 18, 5:00 PM-5:30 PM, Honolulu/Kahuku
Ellipsometric Observation of Ceramic Membranes
R. Tamime, Université Paul Cézanne Aix Marseille
Y. Wyart (Speaker), Université Paul Cézanne Aix Marseille - yvan.wyart@univ-cezanne.fr
L. Siozade, Université Paul Cézanne Aix Marseille
C. Deumié, Université Paul Cézanne Aix Marseille
P. Moulin, Université Paul Cézanne Aix Marseille
The application of membrane processes in the industrial world is impeded by a
major drawback: membrane fouling. During the filtration steps, this fouling can
occur either on the surface or within the pores of the membrane. Where this
fouling occurs not only affects the permeate flux and/or the selectivity but is also
of crucial importance for the membrane regeneration step. The membrane
fouling corresponds to an accumulation of matter which occurs either on the
membrane surface or inside the porous matrix. The structural properties of
membranes (roughness, porosity) have an impact on fouling phenomenon and
must be characterized to develop a fouling control method.
In this work, the angle resolved scattering technique and the analysis of the
scattered wave polarization state using the technique of Ellipsometry of Angle
Resolved Scattering are used to characterize ultrafiltration and microfiltration
membranes and discriminate between them. The main objective of this work is to
show the potential of these recent optical techniques not well defined or used in
the domain of membrane processes. The information, obtained for ceramic
membranes, is compared for different cut-offs (300 kDa, 0.1 µm, 0.45 µm and the
corresponding support). The measurements are made using an instrument called
‘scatterometer’ which allows angular measurements for discrete wavelengths
ranging from UV (325 nm) to the mean IR (10.6 μm). Measurements at low angle
resolution (sampling interval of a few degrees) or at high angle resolution
(sampling interval of a few hundreds of degrees) can be performed. The
experimental setup is composed of a photomultiplier and a synchronous
detection apparatus. The beam is mechanically modulated (chopper). Part of the
beam is deviated upstream (reference) and measured together with the rest of
the beam to avoid the possible fluctuations of the light source power. The laser to
be used is selected through a system of mirrors mounted on a translation plate.
The optical signal is collected by a 1 mm diameter glass fiber that can move
throughout the entire space along the usual angular directions.
First, the angle resolved scattering technique was performed at low and high
resolution mode. For low resolution as well as for high resolution mode, it
appeared difficult to extract one parameter allowing the differentiation of the