The increasing global resource pressure of water scarcity and progressing climate change, renders the research on energy-efficient separation processes a challenge of high urgency. Membranes are regarded as a particularly promising approach in this regard, as they enable significant energy savings compared to conventional thermal processes and can contribute specifically to the purification of drinking water. Of particular interest are membranes exhibiting advanced, multifunctional properties that extend beyond mere mass separation. Polyelectrolytes (PEs), which are polymers with electrolytes in their repeating units, have proven to be interesting substances for this purpose.

In our working group, we are addressing this problem by producing polyelectrolyte membranes using the environmentally friendly aqueous phase separation process. The charge of strong polyelectrolytes is almost independent of the pH value, whereas that of weak polyelectrolytes depends on it. The pHIPS (pH-Induced Phase Separation) process exploits the fact that two oppositely charged PEs form an insoluble polyelectrolyte complex in an aqueous solution. When preparing the polymer solution, a pH range is selected in which both PEs are not present in a charged state at the same time and only precipitate when placed in a coagulation bath with a different pH value.

In this work, the pHIPS process should be further investigated by testing novel PE-pairs and the following characterization of these membranes. This work will focus on screening different polyelectrolyte combinations and possible additives to find a suitable solution for membrane fabrication. The scope of the work package can be adjusted according to the respective work (MA, BA, internship...). The work can be carried out in either in German or English and the start time can be chosen flexibly.

Tasks:

• Preparation of polyelectrolyte solutions
• Polymer solution characterization (focus of this topic)
• Membrane characterization

Your Profile:

• Enrolled in Chemistry, Water Science, or similar subjects
• Interested in membrane fabrication
• Good communication skills

Supervisor(s):

• Rik Mittelstedt, M.Sc.

Are you interested in this topic and do you want to play an active role in the fabrication of new sustainable membranes? Then don’t hesitate to write me an e-mail (rik.mittelstedt[at]uni-due.de) or come visit me in my office.