See Overview 2010

Pinar Zeynep Culfaz (promotion date: 3 December 2010)

Microstructured hollow fibers and microsieves: Fabrication, Characterization and Filtration applications

Promotion date: 3. December 2011

Promotor: Prof. Dr. Ir. Rob Lammertink

Assistant Promotor: Prof. Dr. Ing. Matthias Wessling

Microstructured polymeric membranes were investigated. Microstructured templates or molds were used to form a microstructure in the polymer solution and then in the resulting membrane. This technique is called Phase Separation Microfabrication.

Most of the work was on hollow fiber membranes with microstructured outer or inner surfaces. The fabrication of these membranes and the effect of various parameters on the microstructure, the permeability and separation properties of the membranes were described. It was shown that microstructured membranes with the same separation properties as conventional round membranes can be fabricated. However, because these membranes have a microstructured surface, they provide a higher membrane area per volume, which increases productivity.

The fouling behavior of microstructured membranes was explored in dead-end, cross-flow and submerged and aerated filtration operations. The Permeate Flux-Transmembrane Pressure relationship and real-time observation methods such as NMR imaging and Direct Visual Observation were used. It was observed that under certain conditions, microstructured membranes provide less particle deposition and better fouling reversibility, which makes them advantageous.

Was your work fundamental research or more application oriented?

The topics covered were more application-oriented. We made microstructured membranes with the foresight that they will provide advantages during filtration processes. However, to understand the phenomena taking place during the fabrication process and the filtration applications, we needed to focus on more fundamental phenomena, such as surface forces and colloidal interactions. These play an important role in the evolution of the microstructure from the “mold” towards the final membrane and in the particle deposition behavior on the membranes.

Was there a moment during your thesis project that was of special importance?

Actually I made some of my most successful membranes in the third month of my PhD. This resulted to be both good and bad. On the one hand, it was a very good motivation. At the same time, since it was a bit of beginner's luck - let's say, based on an educated guess - I could not keep the same acceleration, at least for a while, after that. After the good start, I still had to make mistakes before reaching the final goal.

Did you manage to get some nice publications and attend to conferences?

We published five papers in three different journals: Journal of Membrane Science, Water Research and Langmuir. We also have a sixth paper submitted.

I attended the 2010 North American Membrane Society / International Congress on Inorganic Membranes Annual Meeting in Washington.

Was there a lot of cooperation between groups?

We worked in the MicroNed project with another PhD student in the Membrane Technology Group, Matias Bikel, with whom we also co-supervised a master student. From this collaboration a paper in the Journal of Membrane Science was published. I also collaborated with the Biophysical Engineering group of the UT and the Chemical Process Engineering department of the Aachen University. We published a joint paper in Langmuir with the colleagues from Aachen.

Can you describe in what way you changed personally during these four years, as a researcher and/or as a scientist?

Many of my knowledge and understanding of scientific phenomena and research was quite scattered, in my mind, when I started my PhD. I can say I still had quite a good basis then. But all this, and in addition what I had learned during my PhD, settled in the correct place in these last four years. This made me a much more critical and independent researcher and scientist.

Do you like to continue being an academic researcher or do you prefer a job in industry?

I definitely want to stay in academia, to teach and to do research. I am currently in my home country, Turkey, where I applied a number of departments/universities to pursue this goal.

What, in your opinion, is important for Mesa+ to stay successful in the future?

Mesa+ embraces a very nice combination of research groups from science and engineering backgrounds. I believe this multidisciplinary approach is very important. While the monthly Mesa+ colloquia and the Mesa+ day bring these people together, more occasions to promote collaborations and share ideas, can make the institute even stronger.