CapWa project


One of the major global challenges of the future will be to ensure access to fresh, potable water. Water vapour is a component of the flue gases produced in many industrial processes. The EU-funded CapWa project (‘Capture of Evaporated Water’) was set up to develop a method of recovering this ‘waste water’ using a single-phase membrane technology, which would lead to considerable energy savings.

The water-selective membranes used in the trial application are hollow-fibre membranes with a fine coating of an extremely hydrophilic polymer developed especially for this project by EMI Twente. We were able to draw on the knowledge and expertise gained in several earlier research projects. A fully developed production process for the membranes, including all production parameters, was transferred to the project partners for further upscaling. The resulting membrane modules have been tested on a semi-industrial scale at a power plant in Israel. It proved possible to recover about 100 litres of water per hour using membranes with a total surface area of 30 m2.


MANN+HUMMEL has more than 75 years of experience in the area of filtration and today is a leading global filtration specialist. They develop solutions for motor cars and industrial applications and enable clean air in interior spaces and the sustainable use of water.

In 2008, MANN+HUMMEL recognized that polyacrylonitrile (PAN) membranes were increasingly used in the water filtration market, which had a clear cost advantage over state of the art polymer membranes. EMI Twente was requested to develop hollow fiber membranes from PAN for the application in the water filtration market. An important requirement was the use of solvents that did not fall under the REACH regulation (Registration, Evaluation, Authorisation and Restriction of Chemicals). After successfully obtaining a proof of principle on the lab scale, the membrane was in a second phase further optimized and scaled up to the pilot scale. The final membrane met the targeted specifications and showed good reproducible water permeability, chemical durability (e.g. NaOCl-cleaning) and a nearly 8 log bacteria reduction. In 2010, they entered the water filtration membrane market with the acquisition of Singapore-based Ultra-Flo, which developed and produced hollow fiber membranes and systems for the water filtration market. Since 2015 MANN+HUMMEL also has full ownership of Microdyn-Nadir, a global supplier of membranes and modules for MF, UF and NF applications.  


Voltea has commercialized a technology for softening of water and desalination using membrane capacitive deionization called CapDI©. In essence, via an electro-dialysis (ED) process, the technology can be used to remove dissolved salt from a variety of water sources ranging from tap water and brackish groundwater to industrial water. EMI Twente was involved in the early development of this technology. Our task was to develop novel cost-effective ion selective membranes suitable for the softening of water and desalination applications using the capacitive deionization technology, fully characterize them and to compare their performance with commercially available membranes using various process conditions. This was done both at the lab and pilot scale. The findings from this research project gave a good overview of the crucial importance of some process parameters and material properties on the performance of the technology.



Evonik Industries identified a potential new application for one of their high-performance polymers, which it believed would create added value when used to produce a gas separation membrane. Polymer features in gas separation applications had already formed the basis of several doctoral research projects at the University of Twente. Evonik Industries asked EMI Twente to conduct a feasibility study to determine whether it would be possible to develop a hollow-fibre membrane suitable for gas separation. Having performed a successful proof-of-principle, we transferred the knowledge and technology needed to manufacture the membrane to Evonik. Our input formed the basis for the further development and commercialization of the SEPURAN® product family (


The cooperation between EMI and Convergence Industry started from the moment Convergence was founded. Although all necessary knowledge of membrane processes could be found in-house, the knowledge of certificated high-pressure membrane test cells at that time was not. Instead of trying to reinvent the wheel, we decided to use the products that EMI could deliver directly. The strong ties our company already had with the University, the Membrane Technology Group and EMI only intensified over the years and visiting them always feels like coming home.


The cooperation works both ways. During the years we have actively redirected clients to EMI that looked for services outside our scope and vice versa. Currently different projects are successfully running with multiple partners in the Netherlands and abroad.


Long story short: EMI can for sure be described as a high-end knowledge cluster where a lot of skilled, pleasant people with a good sense of humour are working and where the professional scientific sky is the limit!


The spinning machine at KAUST was purchased in 2009 and installed by Zandrie Bornemann and co-worker in ~2010 as far as I can remember. Everything was done very professionally, including some practical training. The machine is still in perfect working conditions.