Core Topics
The ‘Microporous Polymers’ department deals with the synthesis and characterisation of customised microporous polymers. The focus here is on developing new materials for membrane applications for filtration and gas separation. New types of monomers are also developed specifically for certain membrane applications. Various chemical and physical techniques are used to modify the membrane surfaces in order to optimise the membrane properties or adapt them specifically to the desired application.
The development of new polymers and membranes is supported by digital methods for simulation and machine learning.
Water contact angle before (left) and after (right) the modification of a membrane surface. (Image from: https://doi.org/10.1002/admi.202000443)
The surface properties of membranes often limit their performance. Therefore, the surface modification of membranes is an attractive strategy to adapt the properties to specific separation problems and can positively influence the properties of the membrane.
Chemical modification of membranes with different surface charges. (Image from: https://doi.org/10.3390/membranes12060580)
We therefore use various modification strategies to change properties such as the hydrophilicity, charge or mechanical stability of membranes. This can help to reduce undesirable effects (such as fouling), generally improve membrane performance (e.g. increase permeation) or improve interaction with specific pollutants.
Modification is usually carried out after the membranes have been manufactured. As a result, properties such as the pore size are retained, while individual properties (e.g. the surface charge) can be specifically adjusted.
In addition to the modification itself, the subsequent characterisation of the membranes is an essential part of our work. We use a variety of modern techniques such as water flow measurements, thermogravimetry, calorimetry, NMR and IR spectroscopy.
The search for suitable membrane materials is often a time-consuming process based on lengthy approaches and experiments. Machine learning can greatly accelerate the development of new membranes. To this end, we utilised a wide range of available data sets, both from published papers and from our own data collected in the past. Machine learning can be used to develop models that better understand and predict the structure-property relationship of membrane materials. Machine learning can be used to optimise all processes from the synthesis of polymers to the characterisation of membranes. From sustainable water treatment to efficient gas separation, these advances have enormous potential.
Adsorption of toxic ions
Image: Hereon/Glass
The manufacture of many products for human consumption has led to an enormous demand for water, which places a heavy burden on and pollutes the water reserves available today. One focus of Hereon is therefore the production of membranes for the treatment of water.
The ‘Microporous Polymers’ department develops high-performance membranes for this purpose, for example to filter micropollutants and heavy metals out of water. One possibility is the use of ion-adsorbing ultrafiltration membranes. These offer an interesting option for removing toxic ions (e.g. chromate) from water. This technology also makes it possible to selectively recover valuable elements such as precious metals from wastewater streams.