Novel methods and materials in development of liquid carrier membranes [Elektronische Ressource] : from the molecule to the process / vorgelegt von Mitja Medved

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• Publié par: rheinisch-westfalischen_technischen_hochschule_-rwth-_aachen
• Publié le: 01 janvier 2006
• Nombre de lectures: 22
• Langue: English
• Poids de l'ouvrage: 19 Mo

Extrait

Novel Methods and Materials in Development
of Liquid Carrier Membranes
From the Molecule to the Process
Von der Fakultät für Maschinenwesen der
Rheinisch-Westfälischen Technischen Hochschule Aachen
zur Erlangung des akademischen Grades eines
Doktors der Ingenieurwissenschaften
genehmigte Dissertation
vorgelegt von
Diplom-Ingenieur Mitja Medved
aus Maribor, Slowenien
Berichter: Universitätsprofessor Dr.-Ing. Thomas Melin
Univ Dr.rer.nat. Marcel Liauw
Tag der mündlichen Prufüng: 21. August 2006
Diese Dissertation ist auf den Internetseiten der Hochschulbibliothek der RWTH Aachen
online verfügbar.Acknowledgements
The booklet at hand is a product of my last seven years’ intense learning, research and
other activities conducted within the frame of Institut für Verfahrenstechnik (IVT) at
Aachen University of Technology. Throughout this period, in which sometimes the work
load appeared to never end, I was luckily surrounded with friendly but also knowledgeable
people. Among them, special thanks goes to those who helped me pull through all the
challenges placed in front of me.
Firstly, I appreciate the endeavors of my doctoral advisor Prof. Dr.-Ing. Thomas Melin
for his supporting and encouraging supervision. I could not have imagined having a better
mentor and advisor, giving me all the (academic) freedom needed for my professional and
personal development.
I would like to thank Prof. Dr.rer.nat. Marcel Liauw, who critically and thoroughly took
over the revision of the thesis as the second advisor.
Many thanks to Mr. Prof. Dr.rer.nat. Peter Wasserscheid, who brought in the idea of
using ionic liquids in membrane separations and provided them to us directly from his
labs. Without him the thesis would definitely concern another research topic.
Some aspects of my work were treated by the students of chemical engineering at IVT
that I supervised as good as I could. In spite of never having really trusted their results,
I am greatly indebted to their contributions. Special credits go to Anand Sundararajan,
Alexander Bischert, Daniel Becker and Clemens Fritzmann.
Much respect deserve my office mate and friend Andreas Nattkemper for putting up with
me and for finding the right words at the right moments. Jochen Küntzel contributed an
extra something to the cheerful working atmosphere in our office. Sharing ideas with Jens
Hoppe stigmatised my brain forever and without him I would certainly be someone else.
A special thanks deserve my successor at the institute Florian Krull for helping me with
the final experiments.
Thanks also to all other colleagues and coworkers of the institute from the lab, both
workshops and secretariat.
And finally, I cannot overstate my gratitude to my longtime companion Ela and her
daughter Katharina, who helped me find an answer to the one of the most important
questions arising in one’s life: Have I ever really loved? It is a great mercy to be able to
answer this in the affirmative.
vO ME! O life! ...of the questions of these recurring;
Of the endless trains of the faithless — of cities fill’d with the foolish;
Of myself forever reproaching myself, (for who more foolish than I, and who more faithless?)
Of eyes that vainly crave the light — of the objects mean — of the struggle ever renew’d;
Of the poor results of all — of the plodding and sordid crowds I see around me;
Of the empty and useless years of the rest — with the rest me interwined;
The question, O me! so sad, recurring — What good amid these, O me, O life?
Answer.
That you are here — that life exists, and identity;
That the powerful play goes on, and you will contribute a verse.
Walt Whitman (1819-1892)
viiTo my parents
For not answering all my questions and...
...for making me seek the answers by myself instead.
ixPreface
Back in 1999, my alternative civilian service approaching its end, I was looking for a job.
For some innate reason I was focusing pharmaceutical industry only. I have to admit
that at that time I already had a very ambitious wish to continue my education carrier
within the frame of PhD studies in the industry. Therefore, I was looking for an advisor,
who would take over the supervision of my work. I led quite long e-mail correspondence
with Prof. Melin whom I knew from Bayer AG, where I did my first industrial working
experience in summer 1996. Meanwhile, I got a position in a big pharmaceutical company
in Slovenia. But then Prof. Melin suggested that it would be much more reasonable to
do the research work at the university and proceed for industry afterwards. He invited
me to Aachen and I quickly decided to follow that call to Germany.
I can well recall my first serious conversation about my future tasks at IVT with Prof.
Melin. It was clear that I would become the member of the „fabulous” membrane group
working on gas and vapour separations with membranes. In the beginning, I should have
worked on the improvement of inorganic membranes, in particular in pin-hole closure
of zeolite and silica membranes using procedure called „opposing reactants geometry”
[1]. After less than a few months of literature review it proved almost impossible to do
proper work without having a clean room [2]. This installation was clearly too expensive
for the current financial situation. We therefore considered a research project on con-
ducting selective catalytic reactions on an in the zeolite membranes [3], but must had
realised soon that prospects were rather poor. Another very interesting topic in ques-
tion was modification of zeolite membranes according to the „ship in a bottle”-principle
[4]. However, apart from expected deficient occupancy of zeolite cages by the carrier,
we would need quite a few dozens of scarce, commercially non-available Y-zeolite mem-
branes. The producer of these membranes was not only in financial troubles but also had
manufacturing problems. Abandoning this option, we envisaged the liquid carrier mem-
brane concept. I wanted to approach the problem of nitrogen-oxygen separation from
unusual perspective: perfluorocarbons (e.g. perflourooctylbromide) were, based on the
famous submerged mouse-experiment [5], currently also discussed in medical science as
temporary intravenous blood substitutes [6, 7]. Intrinsic oxygen solubility of these oxygen
carriers proved to be excitingly high [8]. Due to their surfactant properties they were also
suggested for nonconventional therapy known as liquid ventilation [9]. They were even
considered as fermentation medium in biotechnology [10]. In spite of these advantages,
perfluorocarbons show considerable vapour pressure and are therefore of limited value
in gas and vapour separation by supported liquid (carrier) membranes. Luckily, at this
time, Mr. Prof. Wasserscheid introduced us ionic liquids, which appeared to be very
xipromising solvents for development of new and for improvement of existing membranes.
We changed our plans a little bit, working area, however, remained „liquid membranes”
and „facilitated transport liquid membranes”, and bought fume cupboard for chemical
syntheses and experiments. All the equipment was then put into the pilot plant area of
the institute. This chemical corner, recently equipped with two glove-boxes, is still a very
funny, almost exotic sight among other robust engineering equipment placed there.
During the years of research, some other ideas not having much in common with my
primary thesis work were generated. One brainchild here and another there led into
quite time consuming proposal writing: without a „bunch of bucks” no research can be
done. There were proposals on microreactors, on membrane reactor and two on molecular
modelling - one in the field of crystallisation and another in the field of mass transport
mo in zeolite membranes. At least the last topic, molecular modelling, proved to
be a real advantage for my own work. Writing proposals, however, had an important
side effect: I did realise how difficult it is to drag money out of other people’s pockets.
Looking back at this work, I am somehow proud of all the running projects I have been
able to initiate, providing ideas and work for new people to come after me.
Many of those „creative” ideas came into being while attending workshops and conferences
(e.g. ICCMR 2000 Zaragoza, Spain; ICOM 2002 Toulouse, France). I am very grateful for
this continuous policy of IVT, which enabled me in participating these scientific meetings.
At several places I was also able to present my own work in the form of oral presentations
(e.g. ECCE 2001 Nuremberg, Germany) or in the form of posters (e.g. SSCHI 2001 T.
Matliare, Slovakia).
Worth mentioning is in particular the team project of the whole membrane group at
IVT called „the membrane book” [11], where I contributed material for two chapters
(Membranestructures, materialsandmanufacturing; Electrodialysis). Myownexperience
in the field of inorganic membranes together with gathered information from the literature
(as required for the book and as collected in this thesis), from the internet (e.g. [12]) and
personal communications let me become a bit of material scientist as well and helped me
in the line of reasoning throughout the PhD studies.
Fortunately, I also had many opportunities to cooperate with departments of big chemi-
cal companies, especially Bayer AG (Leverkusen) and could attend some very