Application of magnetic micro- and nanoadsorbents in water- and biotechnology – A multiscale optimization problem

Prof. Dr.-Ing. Matthias Franzreb, Institute of Functional Interfaces, Karlsruhe Institute of Technology, Herrmann-von-Helmholtz Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany



Magnetic separations are known for their large scale use in classical industrial areas such as mineral processing or the steel industry. In addition, the use of functionalized magnetic micro particles, so-called magnetic beads, for the isolation and purification of cells, nucleic acids or proteins is common practice in bioanalytical and biomedical applications. In recent years, there has been an increasing interest in the combination of these two techniques in order to achieve large scale separations of toxic water ingredients but also high value biomolecules. However, neither the classical separators, nor magnetic beads developed for analytical puposes are directly suitable for this task, and adopting the process for chemical and biotechnological applications will be a multiscale, multidisciplinary task.


The process development starts at the nanometer level by synthesizing superparamagnetic nanoparticles with surface coatings preventing them from agglomeration. The nanoparticles will be encapsulated in polymeric micro beads manufactured by e.g. emulsion polymerisation. In order to separate the resulting magnetic beads macroscopic separators will be needed, which are specially designed for the application in mind. Finally, the complete process must be understood and optimised. This optimisation can not be done by looking independently at the described steps of different scale and complexity. As an example, very small magnetic beads will have superior binding capacities but will be difficult to separate.


The presentation addresses these multiscale aspects and gives examples of the current state of applying magnetic sorbents in different areas of water- and biotechnology.