From lab to industry: eXo membranes is scaling up ‘super-robust’ epoxy filtration membranes

In January 2026, eXo membranes officially launched as a spin-off from KU Leuven, with the IP exclusively licensed. eXo secured a €700k pre-seed round, backed by membrane and epoxy veterans, as well as steward-owned visionaries. The primary challenge for founders Rhea Verbeke and Laurent Hubert is to create the first beachhead markets for their novel membranes and advance the upscaling roadmap, in parallel.

Rhea Verbeke and Laurent Hubert met long before eXo membranes came into being. “Laurent and I have known each other for over twenty years”, says Rhea. “We went to the European School in Brussels together and have remained friends ever since. Professionally, however, we were doing very different things. Laurent worked in the world of AI, start-ups and venture capital. Meanwhile, I studied Bioscience engineering at the KU Leuven, went on to do a PhD and a post-doc. Now we’ve reconnected professionally and found that our skill sets complement each other very well in that regard, which is proving very useful in this start-up phase.” 

Catalisti: Could we start with the basics of membranes? What does eXo membranes actually do? What makes your membranes different?

Rhea Verbeke: “A membrane is like a sophisticated coffee filter. What makes the membranes we produce special is that they are extremely robust; they are inherently chemically, thermally and mechanically very stable. A good analogy is actually the epoxy adhesives you’re familiar with from your DIY projects at home. They consist of two components: an amine and an epoxy. When you mix them, you get a super-strong adhesive. For about a decade, together with the research group Membrane Technology Group, under the supervision of Professor Ivo Vankelecom, at KU Leuven, I worked on converting those adhesives into membranes. Our hypothesis was that if the adhesives are so strong, then so too will be the membranes we make with them. And that hypothesis got validated, meaning that we now have a platform of filtration membranes that can withstand extreme acid and caustic environments but also solvents, chlorine, and other disinfectants. We can therefore purify heavily contaminated industrial streams or use them in aggressive process streams in the chemical or pharmaceutical industries.”  

Catalisti: How are they made? 

Rhea Verbeke: “You basically coat (or print, if you’d like) our uniquely formulated epoxy layer on a supporting layer, to achieve a membrane sheet. These sheets are then rolled up to obtain a module, which is then used for filtering the contaminated streams. The recipe of the epoxy layer is determined by the use case. In that respect, eXo membranes can respond flexibly to the specific needs of many different industries.”  

Laurent Hubert: “What’s special about what the KU Leuven team and Rhea have developed is that it’s a whole platform. With sandpaper, you have different grades ranging from very coarse to very fine. Membranes are the same, and the beauty of the technology is that by tweaking the building blocks a little, you can really create that entire range, from very coarse to very fine, and everything in between. Our plan is to develop a portfolio that covers as many applications as possible. At the same time, we can respond flexibly to very specific requirements.” 

Scaling up

Catalisti: What are the concrete next steps for you at eXo Membranes? How are you doing that?

Rhea Verbeke: “We created the membranes in the lab on a small scale, but when you show that to people in the industry, they laugh it off as irrelevant. So now we’re working on scaling up the technology. We have a four- to five-year plan for this, involving various funding rounds.”

Laurent Hubert: “Scaling up the production of our membranes is an art in itself. Fortunately, we’re getting a lot of help with that. The surface area of the sheets typically made in the lab is A4 size. We now need to scale up to 37 square metres, with a width of one metre, which is the standard for a large module. That scaling up is less straightforward than you might think. We are now working towards a machine that can produce membranes half a metre wide, an intermediate step. We’re actually building that machine ourselves, piece by piece, to build up our production expertise in-house.”

Rhea Verbeke: “The aim is to achieve continuous membrane production to achieve a competitive price point. It’s a technological challenge because there are a huge number of parameters at play. We need to work with great precision. An epoxy layer, for example, is only 200 microns thick. You can’t be too far off because then the properties of your membrane change.”

Catalisti: Can you bring in expertise to speed this up?

Rhea Verbeke: “That is one of the reasons why we are currently collaborating with a partner in Poland. Their CTO has worked for a long time at another membrane manufacturer. In an ideal world, we could recruit people with extensive experience in toll manufacturing. There are engineers who have been doing this for 40 years. So yes, of course that would speed things up.”

Laurent Hubert: “You can’t just scale up blindly either. We want to do this for real customers with real use cases and requirements, based on specific formulations and filtration capacities. There’s no point in blindly scaling up a number of recipes if nobody wants them. So we’re simultaneously finding out who’s interested and for which process. It’s a chicken-and-egg situation.”

A thriving world

Catalisti: How unique is the technology you have?

Rhea Verbeke: “As far as we know, it is unique, but you cannot know what is happening in each lab all over the world. From the moment we bring our membranes to the market, I reckon there will be a lag time of two to three years. That is why our patent portfolio is so important and why we want to keep expanding it. We hold a number of exclusive patent licences from KU Leuven, and we also intend to file our own patents to protect the technology as effectively as possible.”

Laurent Hubert: “It might sound strange, but you can also look at it another way. If you tell me that other companies are working on this too, and so we’re not the only ones, then we’re living in a world where epoxy membranes are becoming widely available for numerous applications. That’s a better world, in my view. If we can play a leading role in that, then that’s only fitting, given the risk we’ve taken. But a world in which this technology is widely adopted, is better off.” 

Rhea Verbeke: “Indeed. Being able to treat heavily polluted waste streams enables industry to truly 'close the loop'. This allows us to avoid the unnecessary discharge or incineration of waste waters. The fact that many industries still rely on these polluting practices is unjustifiable in the world we live in today. The tension you feel today between the short and long term is immense. The state of the world today is a warning sign: short-termism is unsustainable. It’s outdated. For a long time, a small group of people were able to profit from it, but most people have now woken up to another reality. That’s why we want to work hard on the solutions that are urgently needed.” 

Catalisti: Why did you want to start eXo Membranes?

Rhea Verbeke: “My main motivation stems from my love for our planet. I feel a strong urge to make a more concrete, tangible contribution to a thriving world. At the same time, I consider it a privilege to be able to bring research, on which so many people have worked, to market. It’s intense and demands a lot from me but taking that leap is also super rewarding and energizing. Laurent and I share that view as the founding team of eXo Membranes.” 

Stewards

Catalisti: With eXo Membranes’ steward-ownership model, you’re also making an unconventional choice. Could you explain that a bit more? 

Rhea Verbeke: “There are two principles that characterise steward-owned companies: on the one hand, ‘profit serves the mission’ and, on the other, ‘self-determination’.  The idea behind steward-ownership  is to ensure that the company’s mission remains central, in both the short and long term, by giving the stewards the right to make key decisions within the company. In other words, this means that financial rights, i.e. the financial return on investment, is decoupled from decision-making rights within the company. This neutralises a common conflict of interest that companies often face.” 

“We are perhaps one of the first start-ups in Belgium to be steward owned. It’s not yet very well known here, but in countries like Germany and Denmark it has already gained wider acceptance.”

Catalisti: “Doesn’t the demand for returns keep cropping up among investors?” 

Rhea Verbeke: “Of course, we also want our investors to be compensated for the risk they take, without making that an end in itself. The company’s mission remains paramount here too, by reinvesting as many resources as possible.”  

Laurent Hubert: “I do want to make it clear that the steward-owned model is not a panacea. You are constantly seeking a balance in the dialogue with your investors and carrying the mission forward. Their interests are of great importance to the success of our mission. The fundamental difference comes down to placing alignment based on the mission at the centre from the very start. The beauty of steward ownership is that it forces everyone to sit down around the table and discuss what matters: ‘Given there won’t be a typical “exit”, how do we want the company to evolve?’ That conversation starts on day one.”

Thank you for the pleasant conversation. Good luck, stewards of eXo membranes!

Further information: 

• exomembranes.com

• steward-owned.be

• steward-ownership.com