Final Thesis

Helical Ridge Membranes

Key Info

Basic Information

Chemical Process Engineering
Masterthesis / Bachelorthesis
Focus/Key Topic:
experimental / constructive


Membrane technologies have established as sustainable systems in various industrial applications. In the food and produced water field, membrane applications are regarded resource- and energy-efficient for the treatment of waste and product streams. In medical applications, there was neither blood filtration for kidney patients nor open heart surgery possible without membrane technology. For those purposes, polymeric membranes made from high-tech polymers are utilized.

Performance limitations for membrane technologies occur due to boundary layer effects at the membrane surface. Concentration polarisation means an increasing local concentration of the retained species at the membrane surface. For the controlled reduction of the boundary layer, we develop novel hollow fiber geometries to induce superimposed secondary flow patterns. Those secondary flow patterns imply mixing effects to increase the local mass transport from the membrane surface to the bulk phase.

Our solution approach tackles the conventional fabrication process of wet fiber spinning with phase inversion. We tune the hollow fiber geometry by varying specific process parameters, adding extension modules to the conventional setup or designing novel spinnerets for fiber extrusion.

This research project bases on an internally developed technology to twist hollow fibers during the spinning process. We aim at the fabrication of a cylindrical hollow fiber membrane comprising a ridge on the inner surface. Due to the simultaneous twisting of the hollow fiber, the ridge has a helical orientation along the fiber length. This helical ridge will induce a superimposed secondary flow. In order to create this fiber geometry, we develop novel spinnerets with structural elements to shape the ridge. Furthermore, we fabricate the spinnerets in an Additive Manufacturing approach by printing with our own 3D printers.

If this sounds interesting to you or in case of further questions, do not hesitate to contact me. I will show you around in our labs and introduce you to the project and your possible specific assignments. I am curious about your interest.

The work provides you.

  • Membrane fabrication| Deep understanding of a fundamental field of membrane technology
  • Experimental work| Experience in lab work, design of experiments and advanced membrane characterisation
  • Creativity| Development and execution of individual, creative ideas and concepts
  • 3D printing| Skills in 3D-CAD software and utilization of future-leading 3D printing techniques
  • Teamwork| An extensive supervision by the scientific researcher as well as a supporting team of thesis students and research assistants (HiWis)

You should offer.

  • Self-dependent, systematically and structured working attitude
  • Interest in experimental work and mechanical design
  • Willingness to try out something new
  • Ability to work in a team