Thesis-2008-Becht.pdf (9.9 MB)
A study of charge and hydrodynamic effects in protein ultrafiltration
thesis
posted on 2013-06-27, 13:22 authored by Nils O. BechtThis thesis is concerned with the study of different effects in protein ultrafiltration including
device configuration, solution chemistry and membrane charge In the recent and more
established literature membrane fouling remains a challenging problem that limits the wider
application of ultrafiltration. Thus, investigations which can aid understanding and potentially
reduce membrane fouling are of particular interest and in this study the problem has been
addressed from several different angles
Polyethersulfone membranes were studied at varying pH and two ionic strengths using bovine
serum albumm and lysozyme as the model proteins. The study was conducted both in a stirred
cell and a crossflow configuration in order to evaluate the influence of different system
hydrodynamics on filtration This work was further substantiated through the application of
filtration models An attempt was also made to modify the membrane surface by low temperature
plasma modification with the intention to preferentially alter the characteristics of
the membrane surface Both unmodified and plasma-modified polyethersulfone membranes
were characterised using a range of analytical methods including flux data, streaming potential,
contact angle and MWCO measurements to aid results interpretation.
The research showed that MWCO data quoted by manufacturers is mostly greater than that
obtained during laboratory studies The MWCO technique was also used to highlight
differences between the unmodified and plasma-modified membranes demonstrating that the
modification resulted in a membrane with tighter pores in the lower molecular weight region.
Concentration polarisation effects were found to be reduced as a result of the plasmamodification
The study of protein filtration at different pH and ionic strengths demonstrated
that ionic strength effects were more pronounced than pH effects It was also shown that
changes m the ionic strength can be used to alter the degree of protein rejection for the given
system concentration polarisation was found to be higher during crossflow filtration compared
to stirred cell filtration The thesis adds to existing knowledge in the area of ultrafiltration
emphasizing the importance of device configuration, solution chemistry as well as the potential
of charged membranes
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Chemical Engineering
Publisher
© Nils Oliver BechtPublication date
2008Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.EThOS Persistent ID
uk.bl.ethos.504073Language
- en