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Heat Exchanger Fouling and Cleaning VII
July 1-6, 2007 - Tomar, Portugal
| Editors: |
Hans Müller-Steinhagen, Institute of Technical Thermodynamics, German Aerospace Centre (DLR)
and Institute for Thermodynamics and Thermal Engineering, University of Stuttgart, Germany
M. Reza Malayeri, University of Stuttgart, Germany
A. Paul Watkinson, The University of British Columbia, Canada |
The articles for these proceedings are peer-reviewed.
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INTERACTION OF WHEY PROTEIN WITH MODIFIED STAINLESS STEEL SURFACES
S.S. Premathilaka, The Department of Chemical and Materials Engineering, The University of Auckland Private Bag 92019, Auckland 1142, New Zealand
M.M. Hyland, The Department of Chemical and Materials Engineering, The University of Auckland Private Bag 92019, Auckland 1142 New Zealand
X.D. Chen, The Department of Chemical and Materials Engineering, The University of Auckland Private Bag 92019, Auckland 1142 New Zealand
L.R. Watkins, Department of Physics, University of Auckland, Private Bag 92019, Auckland 1142 New Zealand
B. Bansal, The Department of Chemical and Materials Engineering, The University of Auckland Private Bag 92019, Auckland 1142 New Zealand
ABSTRACT:
Modified stainless steel surfaces were fouled with whey
protein solutions to study the deposition mechanisms and
the effects of surface modification. Stainless steel samples
were coated with diamond-like carbon (DLC) and titanium
nitride (TiN). These surfaces are expected to present
different surface chemistries to stainless steel in terms of
their functional groups and hydrophobic or hydrophilic
nature. Thus, it is expected that foulant-surface interactions
will differ for the various fouled surfaces.
The substrates were exposed to a flowing whey protein
solution in a fouling rig designed to achieve laminar flow.
X-ray Photoelectron Spectroscopy (XPS) was used to study
the initial protein-surface interactions of samples fouled for
1 minute at 75°C. Ellipsometry was used to study the
fouling and cleaning performance of samples fouled at 75°C
and 85°C for up to 30 minutes followed by ultrasonic
caustic cleaning of selected samples.
XPS showed the presence of similar protein functional
groups on all fouled surfaces. The bonding mechanisms
during fouling of DLC is different to the stainless steel and
TiN surfaces. The peptide link played a more active role at
the deposit-surface interface for the non-polar DLC surface,
while it was less significant for the two polar surfaces.
Ellipsometry revealed that for the three surfaces, fouling
increased in the order DLC<SS<TiN, and cleanability
increased in the order TiN<SS<DLC. Furthermore, the
nature of the surface influenced the structure of the deposit
after the initial protein layer was formed.
It was concluded that the surface chemistry can
influence the deposition mechanisms in terms of the
orientation of protein functional groups as well as the
amount of fouling, the structure of the deposit and hence the
deposit removal behaviour.
S.S. Premathilaka, M.M. Hyland, X.D. Chen, L.R. Watkins, and B. Bansal, "INTERACTION OF WHEY PROTEIN WITH MODIFIED STAINLESS STEEL SURFACES" in "Heat Exchanger Fouling and Cleaning VII", Hans Müller-Steinhagen, Institute of Technical Thermodynamics, German Aerospace Centre (DLR)
and Institute for Thermodynamics and Thermal Engineering, University of Stuttgart, Germany
M. Reza Malayeri, University of Stuttgart, Germany
A. Paul Watkinson, The University of British Columbia, Canada
Eds, ECI
Symposium Series, Volume RP5 (2007). http://services.bepress.com/eci/heatexchanger2007/21
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