 ThinkTek Hawaii, civil engagement lives here. Welcome to another episode of A Likeable Science here on ThinkTek Hawaii. I'm your host Ethan Allen, you're in the ThinkTek studios. And joining me via Skype today is Dr. Jeffrey McCutcheon from the University of Connecticut. Welcome, Jeff. Thank you very much for having me. Yeah. Jeffrey is the Executive Director of the Frauhofer USA Center for Energy Innovation and also he's an associate professor in the Department of Chemical and Biomolecular Engineering at the University of Connecticut. That's quite a mouthful there. Tell us a little bit about this center. Sounds intriguing. Sure. So the center is really a collaborative effort between the state of Connecticut and the German government. The German government funds a very large network of Frauhofer centers. Frauhofer is, I would say, a well-known organization that focuses on applied science R&D, mostly trying to bring new technologies to market. So what Frauhofer does is it sets up shops in other countries to try to tap into talent pools and the creativity of scientists and engineers overseas, as well as find new markets for German technology and tries to hybridize German technology with other countries' technology. So it's a really unique opportunity to collaborate with the state of Germany and its scientists. Our primary focus is in separations technology, so everything from cleaning water to trying to separate solvents and recycle solvents to separating different gases and even separating vapors such as removing water from ethanol or butanol. So there's many things that we work on. It's a pretty interesting center for that reason. Cool. No, it sounds very worthwhile, too. And the longer I do this show and the more I realize it's the applications of science in the real world that really help people understand science. That's what this likeable science show is all about. It's helping people understand that science isn't something that's just done in a laboratory somewhere for no reason. It's stuff that actually gets used out in the real world and makes an impact on people's lives. So today we're going to be talking with Jeffrey here about membranes and particularly about reverse osmosis in this process, which really does, I mean, tremendous, tremendous impact on people's lives all around the world now, right? So I mean, water touches so much of what we do, not just the water that comes out of our tap. But everything that you wear, that you eat, that you touch has been processed or made using some kind of water. We have a water footprint for everything that we do, in fact. And that's important for us to understand how technologies like membranes, like reverse osmosis, can actually increase the amount of water that humanity has available to it that allows it to do more, to make more, to increase our standard of living and increase our health. Right, right. This whole sort of indirect use of water is very unappreciated, I think. This shirt I'm wearing, for instance, probably took about 70 gallons of water to produce. A cup of coffee will take 25 gallons, a glass of wine, 30 gallons, a glass of milk, 50 gallons, because you've got to raise the grass and then raise the cow and then process the milk, right, and transport it. All these things take water, right? That's right. And people don't like to not have their coffee or not have their shirt, right? They want to be able to have these things to improve their own livelihoods. That means that we as humans must find alternative sources for water. Mother Nature does a great job recycling our water resources. However, as more people exist on our planet and as those people want to live a higher standard of living, their own water footprints, their indirect water use becomes quite substantial in comparison to where we as humanity was just 50 years ago. And so it's important that we augment our water supplies by looking at non-traditional water sources like the ocean or wastewater to augment those supplies. Right. Traditionally, all of our water we've gotten, well, a great deal of water in the U.S. at least has been gotten from the groundwater through aquifers. And many of these are now being pumped down, basically, and they realize the aquifers are not replenishing as fast as we are pumping it out and they're drilling deeper into them, pulling out more water faster, causing, in some cases, a rather unfortunate collapse of the whole aquifer above it and the subsidence of ground. But that's not a real focus today. We really want to talk a little bit about what it is you've really worked on, which is this amazing ability to start pulling freshwater back out of salt water or freshwater out of water that has various salts and other contaminants in it. And that's a process of reverse osmosis, right? Yes. So maybe you can start out by telling us a little bit about, sort of, in general, what osmosis itself is and then what reverse osmosis is. Sure. Whenever I think about osmosis, I'm drawn to the old Calvin and Hobbes cartoon where he puts his book under his pillow at night because he hasn't studied for a test the next day. And he's like, I'm going to learn by osmosis. What's that word? And that's because osmosis is actually a relatively complicated phenomena, but put simply, it's simply the movement of molecules or mass from an area of high concentration to an area of low concentration. In the case of osmosis in seawater or salt water, if you increase the concentration of salt in that water, it wants to absorb more water. And so the water will move from a relatively low concentration salt to a relatively high concentration salt. Now, it would normally do that anyway, just by simple mixing. But if you put a membrane in between those two water sources, then the water will move essentially down its own concentration gradient or up its salt concentration gradient. So there's really two ways to look at osmosis, but from an area of low concentration to high concentration when it comes to salinity and water is a good way to think about how osmosis works. Right. And then that sets you up for this reverse osmosis business, which is essentially to push it against that gradient, to push basically the fresh water out of salt water while keeping the salt concentration high on the one side of the membrane and very low on the other, right? With the concern of getting too technical, this is really a question about water activity, how much activity water exhibits. And you can add pressure to water hydraulically and that forces water against its own concentration gradients, its own activity gradients, thereby counteracting this osmotic effect that's caused by the salt that's present in the water. You're essentially squeezing the water out of the salt water. Right. Even though nature doesn't really want you to do that, that's why you have to apply so much external energy to do that. And that's what we call reverse osmosis. Right. And the membrane there has to be of a sort that will allow the water molecules to pass through, but not the salt, not the salt ions, basically, right? And that's where the real trick is when you're making a membrane that does this kind of desalination or purification technology, is that the membrane has to be of a type of material that won't let salt pass. And I'll tell you this, salt's a pretty small thing. It's a very small molecule. Just the small ions are maybe a handful of angstroms that's 10 to the minus 10 meters in diameter. And for a membrane to be made with such perfection that no holes exist that are larger than the thousands of a human hair in diameter, like that's really impressive for a manufacturing technique to make a membrane that could do that. Right. Because you have it has to be permeable to the water still, which water itself has a certain H2O is a certain size molecule, not all that different from the sodium and chloride ions, right? That's right, because a water molecule is about 1.8 angstroms in diameter, a sodium or chloride ion. They are about three angstroms in diameter, but then they tend to associate with water molecules, so that makes their effective size bigger. And that allows the separation to be a more effective with a membrane. But still, to get selectivity between something that is about 1.8 angstroms and maybe a handful more angstroms in size, that's very difficult. Right, right. So what you have to do is you have to make a very dense membrane, a dense polymer that has no defects, no holes, no nothing, and it is so dense that it can discriminate between these two very small molecules. And the only way to make that still permeable to water is to make it extremely thin. And to make something extremely thin with almost no defects and no holes is an interesting challenge. It's what reverse osmosis membrane technology has sort of solved that problem today. Right, so for years, I mean, RO, as it's often called, has been around now for decades and decades and fairly, well, correct me if I'm wrong here, but they've really used pretty much the same kind of membranes this whole time, right? They started with membranes that were made of cellulosic materials, so essentially naturally derived polymers that could be cast into these membranes like you would take Play-Doh and roll it out with a spindle or something like that. It's not quite like that, but that's the idea of how they used to make membranes back in the 60s. Then the 80s came along and this guy named John Kedot came up with this really clever technique of making reverse osmosis membranes by causing a molecule within a mean chemistry to react with a nasty chloride chemistry to create what we all now know as nylon. But he picked certain chemistry is which created a very specific nylon structure that allowed for this extremely good selectivity to exist, yet still create a very, very thin membrane to allow water to permeate. Right, and this has been sort of the workhorse of RO for years and it's great. It does a job pretty well that requires a certain amount of pressure to push the water through it, not too much pressure, and these membranes hold up pretty well, again, that they last for a while, again, depending I guess on what you may have in your water. But nonetheless, RO has only limited usage. You do have to pull these filters out, either replace them or clean them. There's a certain amount of need for some technical sophistication when you're maintaining a RO system, correct? Yes, it's challenging. And interestingly enough, the technology that was developed back in the 80s hasn't really changed much for reverse osmosis companies in the last 35 years. The technology is pretty much the same then as it is now. And that has led to these limitations of reverse osmosis, such as high pressure operation, propensity to foul, to clog up with all kinds of organic gunk in an organic gunk. And that's been a major problem that RO faces today. Yeah. Think about it. Yeah, go ahead. I was going to say, I see this in some of the work I've done out in the Pacific Islands, where they've put reverse osmosis systems out on relatively remote sites, and they work fine for a while, and then the membrane fouls, and there's nobody around with the technological sophistication to change it, or they don't have the replacement membrane or whatever, and the system just sits there useless after a little while. Yeah, and that's an expensive option. I mean, these are not cheap membranes, even though their cost has decreased. To replace membranes is very difficult, and so what people have done is they've designed systems around that limitation. They've designed systems with extensive pretreatment and softening and filtration. It's like almost the system that pretreats the water before it gets to the RO is five times larger than the RO system itself. I was visiting a desalination reverse osmosis desalination plant in China, and of the entire footprint of this desalination plant, 85% of the plant was pretreatment, and the RO was only a small corner of the plant. Really, huh? And so really RO only wants to treat very clean, salty water. Yeah, it can't have anything else. Fascinating stuff. So this is great. This is a great overview of the challenges we face, the issues, and of course we need, and we talked earlier about the need for more clean water. Now we understand this reverse osmosis, and when we come back after the break, we're gonna really talk more now about what you've developed that really is a breakthrough here in terms of it's reduced the membrane thickness by a tremendous amount, kept the membrane very smooth so it doesn't foul, and it's hopefully going to essentially revolutionize reverse osmosis. So, Jeffrey McCutcheon from University of Connecticut will be with me when we come back here after a brief break here on Think Tech Hawaii. I'm your host Ethan Allen. We'll see you in one minute. Hey, Stan Energyman here on Think Tech Hawaii, and they won't let me do political commentary, so I'm stuck doing energy stuff, but I really like energy stuff, so I'm gonna keep on doing it. So join me every Friday on Stan Energyman at lunchtime, at noon, on my lunch hour. We're gonna talk about everything energy, especially if it begins with the word hydrogen. We're gonna definitely be talking about it. We'll talk about how we can make Hawaii cleaner, how we can make the world a better place, just basically save the planet. Even Miss America can't even talk about stuff like that anymore. We got it nailed down here. So we'll see you on Friday at noon with Stan Energyman. Aloha. Hello, I'm Dave Stevens, host of the Cyber Underground. This is where we discuss everything that relates to computers that just kind of scare you out of your mind. So come join us every week here on ThinkTechHawaii.com 1 p.m. on Friday afternoons, and then you can go see all our episodes on YouTube. Just look up the Cyber Underground on YouTube. All our shows will show up, and please follow us. We're always giving you current, relevant information to protect you. Keepin' you safe. Aloha. We're back here on Likeable Science. I'm your host Ethan Allen. Today here on ThinkTech Hawaii, we have Dr. Geoffrey McCutcheon joining us from the University of Connecticut. We're talking about marvelous membranes and really about reverse osmosis. It's an amazing process to push fresh water out of salt water by having a membrane that will catch and block the salt but let the water go through. And in the first part of the show, Geoff was explaining how this technology has been around now since, well, 1980s, I guess, a relatively good technology with a nylon-based membrane. But still, the membranes are fairly thick, require a good deal of pressure to get through that they are prone to fouling up with any organic debris. And so, Geoffrey, maybe you can just start us out here by talking about sort of, you made this realization that this was, these were challenges, so what did you do? Well, I think where I like to start is talk about how they're made now. Okay, sure. And kind of give everyone a understanding of those limitations and where they really come from. And because it's a technology that was really born in the 1980s, late 70s even, and hasn't changed much since, I began to think about this just from the perspective of why hasn't it changed? And the way that it works now, and your viewers may be able to visualize this clearly just by thinking about how oil and water separate. If you put oil or any kind of organic solvent on the water, it simply flows on top of the water. Now, what we can do is we can use that interface between those two phases as a location to form this nylon, this polyamide, we call it, by placing one monomer in the aqueous phase, the water phase, and one monomer in the organic phase. And so when you do that, the reaction occurs right at the interface. We call this interfacial polymerization. It's a well-understood term in the membrane community and the reverse osmosis membrane community in particular because it forms these ultra-thin films. I'd invite your viewers to look up the nylon rope trick on YouTube and they would be able to see how this interfacial polymerization can create nylon rope. Just so happens that reverse osmosis membrane manufacturers found a way to make this very thin film into a membrane by placing the aqueous phase onto a porous supporting material to form that nylon directly on top of this porous support to create the RO membrane. No, that's very neat, very clean, okay? So what happened when we did that is that we saw that the membrane grew and it was relatively thin, still much less than one micron in thickness. But unfortunately, it's uncontrollable. You can't control the thickness. It just sort of stops because the film forms then the reactants can only get to the interface that exists between these two phases. So it's self-limits and it's also somewhat messy. It just creates blobs of polymer. We don't know why the roughness occurs, but roughness is endemic to these membranes. They're very rough. It creates these peaks and valleys, these nooks and crannies, which cause places for phallus and salts and organics to lodge themselves in and are very difficult to remove. Okay, and so you said it's about a micron thick membrane? About, actually it's about one-tenth of a micron thick. So about 100 nanometers thick. Okay, and so yes, a micron is a thousandth of a millimeter. A micron is a thousandth of a millimeter, yeah. Right, that's very small. You're making too much on camera. I don't know if I like this. So yeah, it's down in the nanometer range. And a nanometer, as I've often been told, or I like to think of it, is a nanometer is the amount that your fingernails grow in one second, so. I've never heard that. Anyhow, so okay, so this is great. These are the limitations. You've got this technology that they've run with, but it's got these limitations that it builds these membranes out of certain thickness that it determines the membranes aren't very smooth, which causes problems for their prolonged use because stuff catches in them and fouls them up. That's right, but over the course of the last 30 years, people have made money selling them. So there hasn't been a real need to make a huge change, but it has caused problems in the design of systems around them. And very huge costs are expended to protect these membranes, which are fragile and relatively untunable in their properties. And that's caused me to think, well, there's gotta be a better way. Okay. There's gotta be a better way. So what's the better way? Well, we have so many ways to manufacture thin films. Very, very thin films that can be used in anything from solar cells to coatings on any surface for any reason. And so I began to think about how you can sort of print materials. Problem with most printing is that it's actually quite thick. There's their microns thick of printing. And when you're talking about many microns, it's very, very thick for a membrane. We think in nanometers all the time, the way your fingernails grow. We have to think like that. So how do we get very, very fine thin films deposited on the surface without having to rely on this interfacial phenomenon that's messy and chemically intense and requires this sort of uncontrolled box? And so we came up with the idea of printing membranes by depositing monomers and all-protein films onto surfaces. We deposit the amine and the acid chloride onto a surface and they react to form the nylon right on that surface. Rather than doing it between two surfaces. That's the approach. Yes, so there's a surface that supports the membrane because these are very thin polyamides. As I said before, they're 100 nanometers thick. So if you try to pick that up, you just fall apart in your hands. So they're actually supported by this larger, I would call it a scrim or a supporting material, which is a cast polymer on top of a polyester non-woven. And that's what actually supports the membrane. We can build the membrane directly on top of that supporting structure through a type of printing approach that uses something called electrospray. Okay. And that avoids and the problems of this so-called interfacial chemistry where you're trying to do it between two layers of aqueous and a oily layer. That's right. Okay. That's right. You spray, you've got a lot more control over how much you're putting down when and where, right? Absolutely. And I think that's actually one of the unique aspects of this technique. Yes, we can control things like thickness or make a smoother film. And we might get to that in a little bit of why that is. But one of the really value-added propositions of this technique is the fact that we use very little chemicals to do it. Because we're not relying on big baths of liquid and large amounts of waste, we're just, whatever forms in the membrane, we are depositing ourselves, which means we estimate we can use probably 95% less volume of chemicals to make the same amount of membrane area as conventional techniques. That should be a huge savings in it, absolutely. And so these membranes, Think about it, go ahead. These membranes, you make how thick or how thin are they instead of being 100 nanometers? We have made them as thin as 15 nanometers and as thick as 160 nanometers. And the reason we demonstrated that entire range is because we wanted to show we could create, have that level of control. We can control the thickness. In our recent publication, we've been able to control thickness to about four nanometer increments, which is fairly unheard of today as reverse osmosis membrane industry. And the plus end of making the membrane thinner is that of course you need less pressure which means there's less energy use, right? That's right. If you can make them thinner, you increase what's called the permeance of the membrane for water and that allows you to use less pressure. But it's important to understand that you may not always want an ultra thin membrane. If you're operating at a high pressure environment, say for sea water desalination, you might need the membrane a little thicker, a little bit more robust. If you can operate with like an under sink reverse osmosis system at very low salinity, you can maybe get away with a thinner membrane or if you're working on other technologies like forward osmosis, which is something that I'm also familiar with, you can get away with a very thin membrane because there's no pressure involved. So you can actually tailor your membrane properties for the process that you have, whereas today there is some tailor ability by just changing the chemistry, but we can now independently change the chemistry, the thickness and the roughness unlike what they could do today. Right, and again, then by making your membrane smoother, you leave less space for salts, for bacteria, for anything to catch in it to crudder it up to foul up the membrane, therefore it's life should be longer too, right? That's right, that's right. And I think it's important to realize also something about membranes when we're thinking about water treatment is that all membranes are gonna foul. There's always gonna be some small amount of organic material you have to worry about. Even the smoothest of surface is going to foul. It might foul slower, but eventually something's gonna stick to it. What's important is that the surface is cleanable and if you're trying to clean a rough surface that's hard to do because things sticking it. Think about trying to like clean concrete if it's rough. You can scrub and scrub and scrub and stuff's down in the valley there. You can't get it unless you like spray it out with a hose or something. But if you have a smooth surface, it's really easy to clean. Think about a linoleum floor. It's really easy to wipe things up. And so we wanna make membranes like that so that when we eventually clean them with chemicals or clean them with high amounts of flow or even maybe even backfalsing, that organic material, that inorganic salt material will just come right off very easily. Okay, this is really truly amazing stuff. And immediately you can see the applications of this. This could really revolutionize RO in terms of making it more usable in more situations in more places, lower costs, higher capacity, longer life for your system between maintenance, more easily maintained and you wouldn't have to replace the membrane. So sort of a dozen ways there that I can see your work is gonna have impact on the field. I appreciate the encouragement. There are a number of challenges that remain, including scale up and showing the potential of scale up of the technique, as well as improving the performance of the membranes themselves to be more robust and to have maybe a slightly higher selectivity. They're already quite selective and in our tests, they match or exceeded some of the reverse osmosis membranes that we tested them against. But to get from that to a technology that is commercialized and sold, there's a major challenge there to do that. Not only am I up against an entrenched mature technology in reverse osmosis membranes today, but I'm an academic and academics sometimes can't be academics and businessmen at the exact same time. Or if they try, they do both poorly. So if you wanted to talk about the role of academics as apreneurship, that might be a different episode. But I am certainly interested in seeing where this can go as a commercial technology and I'm interested in trying to identify ways to bring this to the marketplace. Super. Hey, well, Jeffrey, thank you so much for talking with us today. It's been really enlightening, really very inspiring, actually, to hear your work and to learn more about this. And I wish you the absolute best in getting this out and getting it widespread. And we'll look forward, maybe we'll get you back on here another couple of years and hear where all this is gone, right? I would love that, Ethan. Thank you. All right, well, thank you very much. So we've been talking with Jeffrey McCutcheon from the University of Connecticut all about marvelous membranes he's developed. And I'm your host, Ethan Allen. This is likeable science on Think Tech Hawaii. We'll see you next week.