To allow circular economy concepts it is essential to re-use water and material streams as much as possible. However, closure of water cycles is often accompanied by accumulation of salts. In practice, this is a mixture of desired ions (e.g. nutrients) and undesired ions (e.g. Na+), which are difficult to separate. Therefore, there is an urgent need for new technologies for selective ion separations to prevents waste streams and to maximize the closure of water and material loops.
Ion-Selective Electro Dialysis has been identified as a promising solution for various feedstocks containing a mixture of two or more salts. Electro Dialysis is a desalination process which could be adapted to make it ion-selective. This requires the use of ion-selective membranes (cation-selective and/or anion-selective). Here, the required selectivity can be obtained due to differences in affinity and/or mobility of the various ions for these membranes. Currently, such membranes exist, but they show low ion fluxes. This results in high electricity costs per kg of treated feedstock. The aim of this project is therefore to develop a new generation of high flux - high selectivity Electro Dialysis process with minimal capital costs and low electricity consumption.
A technical setup will be designed and experimentally validated for various multi-ion aqueous solutions, both synthetic as well as real life feedstocks. Potential interesting feedstocks contain binary mixtures of the key ions Na/K, NO3/PO4 and multi-component mixtures of these ions, i.e. solutions contaminated with scaling ions such Ca and Mg. Key performance indicators to be determined are ion selectivity and ion fluxes through the membranes, and their relationship with electrical parameters such as cell voltage, and current density, as well as other design/operational parameters such as properties of the membranes, channel velocity, etc.
At the same time Ion-Selective Electro Dialysis will be modelled in depth. Besides an adequate process description, this model will be also used to optimize the process e.g. by determination of the rate-limiting step, and mass transfer resistances, etc. This allows a further optimization of the process and the equipment.
Cooperation Industrial partner(s) and Wageningen Research / Wageningen University
We are looking for companies who are active in the use and the development of electrochemical separations for ions. These can be for example the selective removal of sodium and chloride from nutrients, the seperation of carbonic acids etc... If you are a OEM technology developer or a end-user in the food- and dairy industries this will help you making your company more efficient and circular on the use of water and resources.
Foreseen deliverables are the theoretical and practical proof of principle for an economical feasible process based on Ion-Selective Electro Dialysis and validated in one or more applications, e.g. in the horticulture or dairy industry.
Benefits for the partners are the possibilities to bring their own use-cases and have them developed. The results are business cases on innovative selective ion-separation technologies and the demonstration in applications.
This project is a cooperation between the industrial partner(s), Wageningen Research and Wageningen University. Therefore, we can address both industrial needs, as well as fundamental knowledge development and knowledge valorization.
The project runs for about 4 years, covers both fundamental and applied research and development, and utilizes a unique integrated approach:
- Fundamental research: Wageningen University – Environmental Technology Group, PhD researcher
- Applied research: Wageningen Food and Biobased Research (WUR-FBR) together with a consortium of partners
The project allows for both long term partnership as well as short term participation.
Deadline of the call for partners
1 March 2020