Solvent Resistant Nanofiltration Membranes
Promotion date: 11. November 2011
Promotor: Prof.dr. ing. Mattias Wessling
Assistant promotor: Dr. Dimitris Stamatialis
The use of first generation NF-membranes presents difficulties in organic solvents. Excessive swelling and dissolution were often observed. The main aim here was to develop membranes for solvent resistant nanofiltration (SRNF).
Composite polydimethylsiloxane/ceramic membranes were prepared by coating on the inside of the commercial α-alumina porous capillary.
Effects of solvent, solute, membrane properties and of applied process conditions were discussed and characterized.
Flat membranes were prepared by crosslinking polyamide-imide based membranes using hexamethylene di-isocyanate.
Polyimide based hollow fibres were prepared by a new spinning method: ”Chemistry in a spinneret”
The membranes were characterized by solvent permeation and molecular weight cut-off studies.
In what application areas are these membranes used?
Specific applications are found in the pharmaceutical industry. To separate bioactive compounds different process steps are needed whereby solvents have to be interchanged. Some of these are aggressive and classical membranes can dissolve. The solvent has to be filtered out, leaving the active components in the reactor and not damaging the membranes at all.
Also in de-waxing processes in the oil-industry - on different scales than this - and in the food industry, extracting vegetable oils from plants, membranes in various solvents play an important role nowadays.
Were third parties involved in your thesis work?
A Dutch oil and energy company was involved, and also a company in membrane production, separating bio-components. This was SolSep BV from Apeldoorn. Two patents came out of the research. So it was very much applied science, so to say.
In this highly experimental field of research fundamentals are also important. We have to learn better what happens to macromolecules in these separation processes, since sometimes they can be deformed in the flow field in this kind of solvents.
Are you more an experimentalist than a theoretic oriented researcher?
I like the nice interaction with industrial project partners most. Furthermore, I am an engineer from origin regarding science as a tool, not as a purpose. Understanding and explaining processes should lead to better understanding and finally to improvements of the devices.
I learned a lot more about membranes, how they can be characterized and also I gained a deeper insight in the processes that matter in this field. Technicians like Harmen Zwijnenberg for example know exactly what equipment apparatus can be used and what the limitations are. He likes the scientific aspects of the processes very much. He was co-author of two of my papers. Furthermore, a member of the users-committee was co-inventor of one of the patents. So, all aspects of research were intermingled in my thesis project.
Can you mention some of your publications?
The Journal of Membrane Science and Separation & Purification Techniques accepted contributions. Also I was a speaker on the Euromembrane conference in Montpellier in 2009, The North American Membranes Society in Washington, 2010 and the International Conference on Membranes and Membrane Processes in Amsterdam, earlier this year.
What are your future plans?
Right now I am performing contract research for companies at the European Membrane Institute which is started from the Membrane Technology Group successfully by Zandrie Borneman. We work as a kind of external R&D office for companies on research subjects not yet commercial but which are very promising for the future. Also we do advising work. It is a kind of post-doc research job but then closer to application processes within companies. Instead of a post-doc I am now called a senior researcher, which I find very nice.
After this, I definitely like to go and work for an industrial company, as I wished to do ever since I started studying science.
What, in your opinion, is important for Mesa+ to stay successful in the years to come?
I like the PR apartment of Mesa+ very much so. They are very active, promoting science and getting industries and spinoffs involved. The Mesa+ Day is the best organized event at the UT, I believe.