How do you recover valuable solvents from water-heavy, contaminated mixtures—without burning them? PolarASol develops a practical decision framework to help industry recycle polar solvents efficiently, even in the most complex aqueous streams.
In short:
- Focus on recycling water-miscible polar solvents from complex mixtures
- Addresses streams containing salts, organic residues, and large water fractions
- Combines experiments, modelling, and pilot validation
- Delivers a heuristic decision-support toolbox for industry
Missed opportunities for circularity
Polar organic solvents are indispensable in sectors such as polymer production, membrane manufacturing, and pharmaceuticals. Yet once used, they are notoriously difficult to recover. Many solvent streams contain large amounts of water — due to cleaning operations or antisolvent precipitation — and are further complicated by dissolved salts or traces of unreacted chemicals.
When polar solvents mix well with water, conventional recovery becomes technically complex, energy-intensive, and costly. As a result, many of these diluted streams are incinerated, even though they mainly consist of water. This leads to unnecessary energy use, solvent loss, and missed opportunities for circularity. Industry needs clear guidance on when recycling is feasible, and which technologies make sense under which conditions.
About PolarASol
This project develops a heuristic approach to evaluate and select suitable separation technologies for Polar Aqueous Solvent (PolarASol) recycling. Instead of relying on one-size-fits-all solutions, the framework explicitly accounts for how mixture composition affects recovery options.
The approach systematically considers:
- Solvent–water ratios
- Salt concentrations
- Presence of other solvents or organic by-products
By integrating these variables, the project supports informed decision-making on technical feasibility, energy demand, and cost, enabling more robust solvent recycling strategies across multiple industrial sectors.
Expected results and approach
The project builds a process selection toolbox based on a broad set of case studies with varying solvent and impurity compositions. Four main technology domains are assessed:
- Solvent-based separations, such as liquid–liquid extraction
- Membrane technologies, including nanofiltration, reverse osmosis, and pervaporation
- Adsorption-based processes
- Reactive degradation, applied as a polishing step for highly diluted streams
Laboratory experiments provide insight into feasibility and performance, while process development unit (PDU) trials validate selected technologies under realistic conditions. Sensitivity analyses define key thresholds, such as solvent concentration or salt content, that determine whether a recovery route is viable.
Where relevant, downstream thermal purification options, such as mechanical vapor recompression and multi-effect distillation, are evaluated to further enhance solvent recovery.
The outcome is a decision-support framework that helps industry replace incineration with energy-efficient, scalable, and sustainable recycling pathways.
Join us
Interested in reducing solvent losses and energy use in your processes? Join ISPT and explore how smart separation strategies can turn complex waste streams into circular value.
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Let’s get in touch
Irene ten Dam
Boelo Schuur
Otto Tobé
Also in our team
Pieter Vandezande
Acknowledgement & partners
This project is co-funded by TKI-Energy with the supplementary grant 'TKI- Toeslag' for Topconsortia for Knowledge and Innovation (TKI’s) of the Ministry of Climate Policy and Green Growth.
