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Jelena Sekulic (promotion date: 29 October 2004)

Mesoporous and Microporous Titania Membranes

Promotion Date: 29 October 2004

Jelena Sekulic

Membrane technology is of course one of the specialities of this institute, but titania (Titanium Oxyde) is a new material for membranes, which is in certain areas a definite improvement.
It is highly chemically stable in almost all environments and has a pretty good separation performance.

Generally for all membranes the applications are gas separation, nano-filtration (liquid filtration) or pervaporation to separate vapour mixtures.
My membrane is suitable for nano filtration and pervaporation. It is not suitable for gas separation, the pores are a bit too large.

What was your thesis about?

Membrane technology is of course one of the specialities of this institute, but titania (Titanium Oxyde) is a new material for membranes, which is in certain areas a definite improvement. It is highly chemically stable in almost all environments and has a pretty good separation performance.

Could you tell something about possible applications?

Generally for all membranes the applications are gas separation, nano-filtration (liquid filtration) or pervaporation to separate vapour mixtures. My membrane is suitable for nano filtration and pervaporation. It is not suitable for gas separation, the pores are a bit too large.

What gave you the idea to try titania?

We are always trying to improve the existing membranes, material they are made of, separation characteristics, etc. But, studying literature, I realized if you really want to improve membrane chemical stability, titania would be the best option. I persisted and proved my point.

So you succeeded?

Yes. There is a lot of room for improvement, like always: permeability and stability at very high temperatures could be better.

Are you the first one to apply titania?

No, not the very first one, but among the first. There is a German group and a Belgian group working on it as well. All the work is of course highly confidential and done separately.

That was also a point I had to consider in doing this PHD. I did not want to be a competitor in a race, I wanted to do science, e.g. establish the material and characterize it.

What if you and your colleagues in the other groups arrive at exactly the same results?

That would be very remarkable indeed, but usually when two scientists individually work on more or less the same subject, they have their own individual approach, their own skills. Also, the factor luck influences the outcome.

Were are you from and how did you come to Twente University?

I am from Serbia-Montenegro. My boyfriend, now husband, got an offer from this university and after a year I decided that I also wanted to do a PHD, which I did not want when I just graduated. He confirmed Twente University is an excellent place for science, so I applied.

At first I got a research fellow position and after six months a PHD position.

What are your plans?

My husband now works at the research centre of Akzo Nobel, so we will stay in this country. I will look for a job. I would like to stay in research as much as I can, a research position in industry perhaps, but I do have a preference for a postdoc at a university.

Have you travelled a lot during your PHD?

I have been to some conferences, and also to the project meetings of the European Union.

(Jelena’s project was financed by the EU). I did not go to all of them, only when I had something to show. But it was stimulating all the same and I also enjoyed the conferences as well. I have been to Toulouse, Sidney, and in St Petersburg.

What did you enjoy most about your PHD?

I enjoyed almost everything. The challenge - which is the main reason why I am doing what I am doing, and working in a really international group really was a joy.

What didn’t you like?

Well, sometimes I felt a lot of pressure. But that is mostly me, it’s a part of my personality.

And sometimes in science, when it starts going wrong, everything seems to go wrong. In the second year I had a period of about six to eight months in which about nothing worked. In spite of all the psychological support I got from the group, I hated that. But with consistency and a slight change in scientific approach all went well, up to the very end.

For the summary of the thesis, click here.