Understanding and improving separation based on affinity


Recent graduate of the EAMS project, Lisette Sprakel looks back on her experience with the Institute for Sustainable Process Technology during her time as a PhD candidate.

My name is Lisette Sprakel, I was born in Apeldoorn and in 2008 I moved to Enschede where I studied and obtained my master’s degree in Chemical Process Engineering. I started my PhD in the field of Affinity Separations at the University of Twente in 2015, as a part of the group of Sascha Kersten with Boelo Schuur as my promotor. The project was an ISPT project and was a part of the Efficient Liquid Separations, or ELS cluster.

The Efficient Liquid Separations Cluster

Within the Efficient Liquid Separations project I worked on affinity separations. The main objective was to develop a general understanding of these processes and the determining factors. By combining experimental methods with theoretical methods the understanding could be improved and molecular properties could then be related to process characteristics.  A second objective of my research was to design affinity separation processes for the separation of close-boiling systems. For me the focus in this was mainly on polar systems with strong interactions.

The research and findings

I found out that there is always an optimal interaction strength between the affinity agent or solvent and the components of the mixture. Interactions  that are too strong decrease the thermal stability and the solvent’s ability to regenerate. Whereas interactions that are too weak do not result in significant improvements of the separation process. It can be concluded that in general stronger interactions can be applied in liquid-liquid extraction, compared to a processes based on extractive distillation. Furthermore, a method that combines the experimental technique isothermal titration calorimetry and the theoretical technique molecular modeling was successfully applied for predictions of solvent effects in separations of close-boiling polar compounds.

EAMS - Notebook with glasses

Contributing to industrial process efficiency

By improving the understanding of the interactions that are involved and of the effect of molecular structure on the separation process, current industrial processes can be improved and new processes and separations can be designed. This contributes to improving the energy efficiency in the industry and it enables new types of processes. With only a small volume sample or relatively simple calculations, solvent effects can be predicted and new solvents can even be designed. This is especially important because improved flexibility and the design of new types of separation processes will be required when more and more bio-based materials and bio-based processes start being applied in the industry.

Working as a part of the ISPT network

The ISPT is a very professional organization that is a great link between the industrial partners and the academic partners and researchers. The input and feedback from industrial partners was always a valuable contribution to my PhD work.


This project is co-funded with subsidy from the Topsector Energy by the Ministry of Economic Affairs and Climate Policy. Also, this project is co-funded by TKI-E&I with the supplementary grant 'TKI- Toeslag' for Topconsortia for Knowledge and Innovation (TKI’s) of the Ministry of Economic Affairs and Climate Policy.