Climate Money Watchdog
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Dr. Michael S. Wong - Capturing and Disposing of PFAS at 1,000x Speed
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Our guest tonight is Dr. Michael S. Wong, a professor in the Department of Chemical and Biomolecular Engineering at Rice University. He is also professor in the Departments of Chemistry, Civil and Environmental Engineering, and Materials Science and NanoEngineering. He was educated and trained at Caltech, MIT, and UCSB before arriving at Rice in 2001. His research program broadly addresses chemical engineering problems using the tools of materials chemistry, with a particular interest in energy and environmental applications ("catalysis for clean water"). He has received numerous honors, including the MIT TR35 Young Innovator Award, the American Institute of Chemical Engineers (AIChE) Nanoscale Science and Engineering Young Investigator Award, Smithsonian Magazine Young Innovator Award, and the North American Catalysis Society/Southwest Catalysis Society Excellence in Applied Catalysis Award. He is research thrust leader on multifunctional nanomaterials in the NSF-funded NEWT (Nanotechnology Enabled Water Treatment) Engineering Research Center. He is chair of the ACS Division of Catalysis Science and Technology (CATL), and serves on the Applied Catalysis B: Environmental editorial board. Previous experiences include chairmanship of the AIChE Nanoscale Science and Engineering Forum and Chemistry of Materials editorial board membership.
The focus of this podcast is recent work led by Dr. Youngkun Chung, one of Dr. Wong's postdoctoral research associates, which describes a new approach to filtering PFAS from water at 1,000 times the efficiency of methods such as activated carbon. Better still, the captured PFAS can be removed from this new filter medium in a process that renders it safe, and the medium ready for reuse.
Topics covered include:
- Description of PFAS chemicals are
- How they get into the environment
- Limitations of existing filtration approaches
- Details of the new technology
- How Dr. Wong's team at Rice University collaborate to develop technlogies that use chemical engineering to make our environment cleaner.
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Thank you for joining us for another episode of Climate Money Watchdog, where we investigate and report on how federal dollars are being spent on mitigating climate change and protecting the environment. We are a private nonpartisan nonprofit organization that does not accept advertisers or sponsors, so we can only do this work with your support. Please visit us at Climate Money watchdog.org to learn more about us and consider making a donation. My name is Greg Williams, and I learned to investigate and report on waste, fraud, and abuse in federal spending while working at the Project on Government Oversight, or POGO, 30 years ago. I learned to do independent research, as well as to work with confidential informants, or whistle-blowers, to uncover things like overpriced spare parts, like the infamous $435 hammers, and expensive military weapons systems that didn't work as advertised. I was taught by my co-host, Dina Razor, who founded Pogo in 1981 and founded Climate Money Watchdog with me a few years ago. Dina has spent 40 years investigating and sometimes recovering millions of dollars wasted by the Defense Department and other branches of government, both while at Pogo and as an independent journalist, as an author, and as a professional investigator. Our guest tonight is Dr. Michael Wong, a professor in the Department of Chemical and Biomechanical Engineering at Rice University. He's also a professor in the department of chemistry, civil and environmental engineering, and materials science and nano engineering, he was educated and trained at Caltech, MIT, and UCSB before arriving at Rice in 2001 His research program broadly addresses chemical engineering problems using the tools of materials chemistry with a particular interest in energy and environmental applications you might call catalysts for clean water. He has received numerous honors, including the MIT TR 35 Young Innovators Award, the American Institute of Chemical Engineers Nanoscale Science and Engineering Youth Investigator Award, Smithsonian Magazine Young Innovator Award, and the North American Catalysis Society Southwest Catalysis Society Excellence and Applied Catalysis Award. He is research thrust leader on multifunctional nanomaterials in the National Science Foundation funded nanotechnology enabled water treatment engineering research center. He is chair of the ACS Division of Catalysis Science and Technology, and serves on the Applied Catalysis Applied Catalysis B environmental editorial board previous experiences include chairmanship of the AI CHE Nanoscale Science and Engineering Forum and Chemistry of Materials Editorial Board membership. Dina, would you like to say a few words about why we're excited to have Dr. Wang with
Dina Rasor:us? Yes, I'm always excited when we have scientists, and especially ones that apply engineering scientists. My dad was one of the reasons that we're so interested in this is science is doing been doing a pretty good job lately of making up for our politics, in other words, right now we are, of course, worried about earth overreach. We look at pollution stuff as well as looking at climate change, and right now it's going to be very hard to get the federal government to ban PFS, and there it goes. It's going into everything. It's polluting the water. It's, you know, we're living it. You know, we have all gotten rid of our Teflon pans and Teflon walks and all that, but people despair about that. But science can help if it's used correctly. Can help solve this by if he, you know, he's, I mean, had a breakthrough on PFAS filtering, so there is already tons of PFAs, and already in the environment, and we're dumping more in, we're putting more on fertilizer, and maybe the band, the problem with fertilizers, actually a good thing, less PFAs in the water, but you know, fertilizer and everything else is still being put in, so this buys us time. It buys us time, and then when PFAS hopefully does become forbidden, then we can start well. Clean up on all 10, you know, and he's got the technology for that kind of cleanup, so he can be developing it now, and when it's, you know, then we can get serious about how we're going to try to sometimes I call it emptying the ocean with a teaspoon, but at least start, at least start. So I'm very happy to have you with us today, Dr. Wong.
Dr. Michael S. Wong:Thank you for having me. This is a, it's a, it's a fun time to be a scientist and engineer. There's always problems for us to tackle, and, and PFAS is one of them. So, happy to talk about PFAS all day, any day.
Dina Rasor:Okay. Well, why don't we start with the very basics, you know, you're a professor, that's good. The very basics for the listeners, what exactly are PFAS chemicals, and why do the science scientists call it forever chemicals?
Dr. Michael S. Wong:Yeah, I, so I, a little bit about me is that I to expand on to my, of my background, and what I teach is, I do teach chemical engineering, and I teach chemistry and material science and environmental engineering. You know, a lot of that just goes back to my general interest in how do we clean water, how do we protect our environment, and we use the tools of chemistry and chemical engineering to tackle this, you know, problem of contaminated waters and contaminated environment in general, and so for me, you know, PFAS is yet another one of these classes of compounds that has contaminated our waters over the years. I think one of the things that makes PFAS very interesting, and I'll tell you what it stands for, and why it's so different and yet the same compared to the other chemicals that are out there in the environment, is PFAS contain is well, I'll tell you what PFAS stands for. PFAS is an acronym, it is PFAS, it is pronounced PFAS. If you look up the word PFAS in the Oxford English Dictionary, it'll teach you how to pronounce PFAS. It's pronounced PFAs. It stands for per and poly fluory, alkyl substances, and it's not one or two or five or even 10 compounds, it's at least 10,000 compounds, if you use the proper definition of what PFAs is, and if you look at sort of the list of all the PFAs that has ever been made and studied in the world, you can count to over a million of these individual compounds. Thankfully, most of them are not manufactured to the large scale. It's really the ones that we're worried about that are in the environment now, which are the ones being monitored and regulated. So PFAs as a, as a class, as a class of compounds, where they're man-made, all of them are man-made, and they contain mostly carbon, and it contains at least two or more fluorine atoms. So, essentially, these are fluorinated compounds. So,
Dina Rasor:and how many of them out of that 10,000 do you think are the ones you're looking at now that have been massively over manufactured and polluted? How many?
Dr. Michael S. Wong:Yeah, so PFAs has been around for a while, if you look at the full history, and there's been some nice write-ups, and on how long PFAs has been manufactured, it goes back to the 1940s This is a technology or material that was developed, you know, by DuPont to solve a problem that was needed way back then, and they, when I say they, you know, the industry back then needed a compound that allowed things to contain essentially solvents and chemicals in a safe way, and while protecting the containers, and so they wanted something that was nonstick and PFAs, some very clever scientists discovered that if you put a lot of fluorine on top of carbon polymer, basically that you could make this non-stick material, and that was really the start of the beginnings of Teflon, and then the manufacture of Teflon led to the manufacture of this really large class of compounds that we call PFAs, so it's been around in the sort of in the industry and manufactured for many, many decades, and the ones that are in the environment now are the ones that have been made and have leaked out into the environment all these years, and that includes I would say the Pfas literature, you know, contains lots of acronyms, and I'm going to be throwing out two acronyms here: PFOA, and another one is PFOS. We pronounce them, or at least I pronounce them PFOA and PFOS, so these. Two are the most prevalent of the PFAS class of compounds, and PFOA and PFOS are not only monitored but also regulated in the US, as well as other countries in the world,
Greg Williams:and I understand one of the problems with these chemicals is that because we keep inventing new ones, each one of those has to be addressed separately from a regulatory perspective.
Dr. Michael S. Wong:Yeah, it's one of those general questions that has no right or wrong answer. Is how do you attack and address this problem of contamination by chemicals, and so right now, if we are regulating these two monitored compounds called PFOA and PFOS, what about all the other ones, right? And so, and not all the other ones are bad, if that makes a little sense here, you know, PFOA and PFAs, they are known to be bad for our, not only for environment, because it enters the ecosystem into the into the animals, and it also enters into the human body, and so there are studies now that, that, that indicates strong correlation between high concentrations of PFOA and PFAs with with with a lot of documented diseases and health negative health effects, and so, but you have those evidence for PFOA and PFAs, and there are some evidence for other individual compounds in this PFAS family, but what about all the other ones? Right, there's very little information about the health effects of these, of all of the 10, you know, 14,996 you know, or 94 that are not being officially regulated in the US, and so does one wait to develop the evidence to show the negative health effect of any for a particular compound, or do you anticipate that there might be based on a general chemical structure that may look like PFOA, but may be shorter by a chain, or may have a little bit of a slight modification to the chemical structure, so I think there's general approaches to how to handle these other variations of PFOA and PFOS, and so you know, I think one of the challenges is if we are going to remove PFOA and PFAS from the environment, what do we do about the alternate versions of PFOA and PFOS? How do we think about them. How do we deal with them, and those are general questions and ongoing questions that even we, as scientists and engineers, are trying to grapple, you know, because we have to. We have a limited amount of resources to be able to attack all of these compounds as well. So, for now, what we do is look at the most important ones, and the important ones are the ones that are having documented health, negative health effects, and that includes PFOA and PFAs,
Dina Rasor:and give us, give us the listener an idea of what kind of things have this in it, everyday things they use. Now I mentioned Teflon pans and coatings and special coatings, but what, what are the other things that we buy that have it in there, and then how you know how does that get into the drinking water, and what are the health risks? I know this compound question, but it's kind of together.
Dr. Michael S. Wong:Yeah, for sure. Now, yeah, let's.. I'll unpack that in this following way here. PFOA and PFOS, they're not made in the US anymore, so any evidence or any sites that contain PFOA or PFAs, it's from legacy sources, or they are in products that have been made decades ago, and they've ended up in the environment. Okay, so, so there's that aspect. There's this legacy effect of PFOA and PFAs that's been in the environment, it's in our bodies, you know. And, and they used to be found in carpets, in clothing, and, and in cooking, where used to, and they don't manufacture these consumer products with those anymore. They are manufactured with variations of PF or of PFAs, but also many of these consumer products are not made with any fluorine-containing compounds anymore. Also, so there's a move away and a drift away, a deliberate move by some, you know, manufactures to go away from, from PFAs. I would say a major source of PFAs, specifically PFOA and PFOS in the environment. This comes from firefighting foam, so airports I. A military installations, airports, any incident that requires a fire suppression, or any site that requires training, you know, of how to put out a fire, invariably you have to use these, these firefighting foams, and back then they contain PFOA and PFAs, and that's really a major source of these particular two compounds in the US. Nowadays, they're moving away from these PFOA and PFAs containing firefighting foams to well, they call it fluorine-free foams, basically. And so, while that is happening, the impact of the of the PFOA and PFOS is already in the environment. So, there's sort of what's already in the environment, it's from products that have already been used going forward, there are products that do not contain those particular compounds, and so now I think it goes to the what we're trying to do is to figure out how do we remove the PFAs that's in the environment, as well as how do we develop products that don't contain PFAs,
Greg Williams:so how widespread a problem is environmental contamination? Are there is it confined to hotspots or is it more, more pervasive?
Dr. Michael S. Wong:It's more pervasive hotspots, and it's very pervasive as well. People didn't know just how pervasive it was until about two decades ago, when studies started to come out to identify and measure PFOA and PFAS, people looked for PFAS and PFOA because they were the most prevalent, and it's easy to look for because they were used so much in our products. The hotspots are definitely near Superfund sites, industry sites, any site that would have potential uses of, you know, firefighting foam, you would see the foam that contains the PFOA and PFOS. You know what happens to the to the foam when the fire goes out, it sort of gets washed away and it just sort of washes out into into the concrete and to the soil, and then it sort of just settles through the ground, and I think it's just people didn't know, and so in that sense, once the PFOA and PFOS gets into the soil, the sediment eventually gets down to the groundwater, and it just sort of just gets into the water, and it just sort of gets carried away, and that solubility of those compounds in water allows to travel, I mean, in water basins, and it's everywhere in our waters, it's in our sediments, and I mean it's in our air as well, I mean, that's that's a that we can talk about that as well, but there's definitely once it's out in the environment, and it's been out in the environment for decades, it ends up sort of circulating almost in the world. Yeah,
Dina Rasor:what's what's what's the human health risk? What is the thing, man? I know, I know, they maybe haven't figured out every single one, and like the microplastics, we don't know what happens to that credit card we eat each month, but as they call it, what, what is the known concerning health benefits, health problems with people?
Dr. Michael S. Wong:Yeah, well, so it's interesting you ask that, because I think the health effects are generally negative, and what they found so far, it's there's birth defects, connections to certain types of cancers, thyroid disease, liver damage. So this really speaks to just the beginning, I would say, of documenting that the full understanding of the negative health risks of some compounds, and that's where we get to sort of ask the question, is it important to look at other variations of PFAs, and I think for us, and who do this type of research, I think the answer is, yeah, we want to be on the, you know, safer side, so we should be careful, and you know, do we assume the worst? It kind of depends on how you feel about chemicals, and so not all chemicals are bad. I'm a chemical engineer. Chemicals are helpful, they're needed. So, so I think it goes back to how one thinks about chemicals. Are they good, are they bad? To me, I think PFAs is a chemical, but there's certain chemicals that you're definitely, you have to be careful about using, and there's certain chemicals you'll never want to use again, but there's others that you definitely do need, and so, but definitely there are documented health effects for PFOA and for PFAs, and I think as studies continue to come out. We probably will learn more about those two compounds, but as well as other variations of PFAs that are in some of our products. Now, it's interesting you mentioned microplastics, so microplastics is yet another type of contaminant, but the health effects for microplastics is not well established yet. In fact, there's only some ideas or hypotheses, right, that they could be bad or could just be benign, but we don't know. It's a very, very fair question to ask. What are the potential health effects? And so until then, do we wait to see for someone to come out with a health study that tells us it's safe or bad or not, or do we sort of get ahead of it a little bit, and just say, well, maybe we don't need to use everything plastic that contains plastic or containing PFAs, for example, so kind of goes back to how you want to handle and how you kind of live your life a little bit, but to me chemicals are useful, PFAS is a chemical, but there are certainly harmful chemicals that we don't want to use anymore.
Greg Williams:So, how do we deal with this from the perspective of municipal water treatment?
Dr. Michael S. Wong:Right now, the PFAS is in the waters, and there is no best way to remove PFAs, so right now the regulations, as set by the US EPA, is four parts per trillion, which is really, really low, we're talking a couple of, you know, molecules in the many, you know, Olympic-size pools, I mean, how do you remove those small amounts in this large volume of water? Thankfully, these water utilities are meant to do that. They are very good at removing bacteria, they're very good at removing known compounds, known contaminants. PFAS is a new thing, and so the technologies that are built into the water utilities, the drinking water plants, they're not built for that, they're not built to remove those things, and so it's interesting, you know. Do you, how do you deal with it? Because these utilities are not only required to monitor, but at some point they're going to be required to lower and ensure you know those concentrations of compounds are below regulated levels, and so Gary, I think your question was, can we do it, or how do we do
Greg Williams:it, or it is that something that water treatment plants nowadays generally address, or it does. It essentially go unaddressed.
Dr. Michael S. Wong:It's going unaddressed right now. In fact, I think I think it's catching up in the sense that they, they need, they need to monitor, and they're doing that. They know what the regulations are that are coming down the line, and they know that their current technologies do not remove PFAs, if they, in fact, do detect PFAs in the waters that, that come into their, into the treatment plant. So that's way, that's when they, and that's why they're looking for new technologies. It may not be completely new, it could be improved technologies, and and activated carbon works certainly well, but there's a cost issue associated with that, and so some of the things that my group and others around the world are doing are, can we create new technologies to help these water utilities remove PFAs in a ultimately more economical way? It's all going to come down to cost,
Greg Williams:so do we need to make these things 10% more efficient, twice as efficient, 100 times as efficient?
Dr. Michael S. Wong:Yeah, all of the above. I would say the cost of cleaning water is very low as it is now, and if you throw in a treatment technology to take down the PFOA concentration from, you know, let's say 100 PPT to four PPT. I'm just making something up here. You'd have to design a system to be able to do that in within the amount of water that they need to treat in the amount of time and the amount of cost, so 10% is in terms of efficiency is good, 15% is better, but it's going to be a case by case basis, so hard to say at this point, but definitely you want to be several orders of magnitude more than what they're able to do now, so
Greg Williams:so what kind of financial or regulatory pressure does that put on municipalities who are trying to address this issue?
Dr. Michael S. Wong:Yeah, so the drinking water treatment plants, they treat different quantities of water depending on the size of the city that they treat, and so, so if we talk about. It's a small community of 20,000 people that's different from a a city that you have to treat water for a million people, so the treatment costs are different, and, and I think for, and the technologies are different as well, and so it's really going to be a case by case basis, and depending on where you live in the country, if you're attached to a centralized drinking water system, you are going to be drawing water from a water utility. If you are out in outside of a city and you use well water, well, you don't have a treatment plant that will treat the water for you at your well, you have to do something about it yourself. So, the needs are going to be different on who the users are going to be, and so I think that that's gonna, that's something that I've, I've grown to really appreciate. You know, not everyone can afford the treatment to remove PFAS, number one, and number two, it really depends on where you live in the country. So, if you live in a part of the country where you do use 100% of your water from well waters, and it happens to be contaminated with PFAS, your cost of removing PFAS is going to be different from someone who lives in the city.
Greg Williams:So, let's say I live in a rural area that's that's near a decommissioned air force base, and you know, am I looking at a solution that's going to cost me hundreds of dollars, 1000s of dollars, or hundreds of 1000s of dollars?
Dr. Michael S. Wong:Yeah, everything's on the table at this point here. I mean, who can afford $100,000 you know, technology if you have a community of 10, right, you can get the technology to work, but Who's going to pay for
Dina Rasor:it?
Dr. Michael S. Wong:I don't know how to answer that. All I know is how you know what the technology needs are, and how to design something, and I think that's going to be where the cost issue will come into play, that'll dictate the type of technologies that we're going to use. So, so there's not going to be a silver bullet to remove PFAs, it's going to be something that would be, I would say, pretty bespoke, attuned to the needs of the community to enter to the target levels that you really need, you know, so if you are living in a place where your contamination level is maybe 10 ppt higher than than the regulations, and then the treatment cost is going to be a lot less than, say, if you're located next to, and you know, a military, you know, sites that's no longer used, no one's taking care of it, but now your concentrations are 100 ppb, I'm making something up again, there's just a whole lot more pp, you know, key fasts that you have to remove, so it's going to be the quantity of PFAs that's going to dictate a lot that the cost and the and the efficiencies that that you ultimately will need.
Dina Rasor:Okay. Well, let's, let's get to the technology now. Let's get this is the part I'll find, kind of find fun. Yeah, so it's called a, it's called a layered double hydroxide, or
Dr. Michael S. Wong:LDH.
Dina Rasor:You can explain that in plain language for people who belong to high school chemistry.
Dr. Michael S. Wong:LDH, that's all you need to know. LDH stands for layer double hydroxide. It's, it's a, it's almost like dirt. I mean, it is dirt. It exists naturally, but you can make it artificially in the lab, and has this particular structure that, that is really good at generally soaking up things, ions and charged molecules, charged species, and in our particular work, we happen to do a little chemical tweak to an LDH material that allows it to really soak up a whole lot of this charged PFAs, and so PFOA and PFOS, PFOS, and PFOA happen to be charged molecules, it has one negative charge, a negative one charge, and that allows it to get pulled into this layered double hydroxide. So, imagine a layered double hydroxide as being another way of thinking about it, is it's a material that can pull in, like a sponge, you know, anything that's negatively charged, so that includes PFOA and PFAS, and so that was that was one of the interesting outcomes that came out of our materials understanding of this LDH material. Yeah,
Dina Rasor:okay, that sounds good. It says the original discovery was done by a grad student in South Korea. So, how did that discovery make its way to Rice University and into your research?
Dr. Michael S. Wong:Yeah, it's called.. it's called Sciences Diffuse. Science, everyone does science, everyone collaborates, and Rice, in particular, were very collaborative. The story is as follows. It's a, it's the, the graduate student who is now my postdoc, Young Kyun Chang. He started,
Dina Rasor:okay, that's how it is.
Dr. Michael S. Wong:Yes, yes. So, so PFAS is a worldwide problem. So, just as we are doing the PFAS research in the US, and I'm in Houston, Texas, I've been doing it for the last six, seven years. Young Kyun and his boss in Korea, they have a PE fast problem. They're looking to develop technologies just like we are, and you know, they have excellent scientists and engineers as well, and they look at things in the same way we do. That's how can we design materials to destroy or to remove or do something to remove it out of the water, and so, so he did this project during his PhD, and it takes a long time to do research, because some things work, some things don't, and in that case it worked well, but it didn't work very well, and so, but he kept on working on it, because he felt the PFAS problem was a huge problem, and when he joined my group at Rice, we were working on PFAS as well, but using a very different approach, and then, and then I said, young, you know, I mean, you have this other project that you should probably continue to continue to work on, happy to support that, you know, just, you know, do all the things that we are trained to do in terms of science and engineering, and your tool is is interesting. Let's, let's continue to work on that, right. And so that's when he brought the project to my group, and he continued on, and eventually he found the results, and this is where the collaborations became very interactive between my colleagues now at in South Korea and here at Rice, and among other professors here at Rice as well. And so we just kind of teamed up, we just added people to the team, and everyone came up with some ideas that made the project go forward, two steps forward, one step back, and eventually got the material to work, got the material to soak up PFOA, not just a little, but a whole lot, and not just PFOA in just DI water, or DI water stands for DIY water, that's the clean water that we get from the lab. We always start with deionized water, but real world, we don't use deionized water, we use real water, and that contains ions and contains salts, and so usually these salts get in the way, and during the time in my group, we've actually figured out, you know, the material this LDH was able to pull out the PFOA in regular water, you know, and it was amazing. So I think that was kind of the one of the one of the nice things is is that the work that initiated in South Korea, for this PFAS problem, brought it over here. We had additional tools, and you know, the internet's a very powerful thing, and we still can't solve the time zone problem, so we always have trouble figuring out when best to talk to them. But I mean, it was really, really young, King was the lead, but we probably have about 1617, co-authors on this paper, everyone pitched in, and at the end of it, eventually we got it published, and, and, and we're continuing to work on it to really make it to a useful material.
Dina Rasor:Okay. Well, what about explaining now the internal structure of it, the copper aluminum layers and the charge imbalances, how that you know the best way you can for average person. How does that work? You know, putting together this metal, and what, and what are you getting this metal to do?
Dr. Michael S. Wong:Yeah, so imagine this layer double hydroxide. The reason why this material is called it's basically a powder, and this powder, this LDH hydroxide, imagine is just sheets of aluminum and stacked on top of one another and in between these stacks is a little bit of water so and charge and so that's the base structure and what the team did was to take out a little bit of the aluminum and throw in some copper and by doing that you still keep the positive charge, aluminum is positive, copper is positive, but it's missing a charge, so aluminum is plus three and then copper is plus two. Well, then you have this sort of missing plus, so that missing plus happens to be to be a proton, and so or sodium, and that that pops out and pops back in, and that allows the PFOA, which is negatively charged, to get pulled in much more easily, so you get this charge attraction that goes inside the layers, and guess what, the layers are not balanced. They're kind of separated, but they're not stuck to one another. So, as soon as PFA goes in, the layers sort of expand a little bit, and then another layer, well, that expands a little bit more. Basically, this is literally a sponge. It really opens up and it pulls in even more PFOA. So, I think that's what people know that about LDH, that it does soak things up, and it does expand a little bit by putting in copper in there. It makes the LDH structure expand a whole lot more, and by pulling in all of this PF away, it just pulls in so much more PFA than anyone's ever sort of imagined, even. And so, but he got it to work,
Greg Williams:so what do you, what do you do with that POA once, once you've captured it?
Dr. Michael S. Wong:Yeah, once you capture it, so I think that that goes back to kind of the one of the one of the big sort of Achilles heels of activated carbon, so activated carbon, just to give a little bit of a comparison here, activated carbon is just literally carbon, and it does pull in PF away, as well as other PFAs, just soaks it up, it's like a sponge as well, doesn't expand, but it's the filter in the, you know, grid of water filter in our pitchers, basically, and eventually, you know that little, little cartridge of carbon, you got to throw it out, and you got to replace it. You don't have to replace it, but if you don't replace it, then it doesn't pull out any more PFAs. So, you know, we have to be pretty, pretty mindful of when you have to replace it, and you don't really regenerate the activated carbon inside the little little cartridge, there. Now you can do that at home, but the problem is that where does it go? Where does that cartridge go? It goes to the landfill. Okay, so that's where that's the problem with, and that's the Achilles heel of activated carbon. LDH is going to soak up all of this PFAs, also, but we're not going to, we're not going to bin it, we're going to actually going, going to go ahead and heat the thing up, break down the PFAs inside the LDH, and then the broken down products leave the layered structure, the layered structure kind of collapses, you might say, and then you can reuse it again. The PFOA that's entrapped in there, it breaks down to form fluoride, so it comes off as fluoride, pops off as co, and, and that's how we break down the the PFAs, and so it doesn't go into landfill, and that's a good thing. Anything that goes into the landfill might get eventually leached out and come out. That's why PFAs in landfills is a problem, because it could come out in the, in the wash.
Dina Rasor:So, you, so you, you say you can destroy it by heating it and using cal calcium carbonate.
Dr. Michael S. Wong:Yeah,
Dina Rasor:how did.. how does that happen? I mean, that means it's destroyed. Is it is it made neutral, so it no longer has its.. its dangerous properties.
Dr. Michael S. Wong:Yeah, pretty much. If you were to heat up the LDH with the PFOA, the molecules will fall apart as co and the fluoride ions. Now, the fluoride by itself, you throw in the calcium in there, and the calcium just captures and just holds on to that fluoride. Then you have this calcium fluoride, and that, that, that's basically calcite. It doesn't go away, it's, it's locked in as rock, essentially. And so that's why we use the calcium carbonate. It helps to keep the fluoride from escaping into the gas or washing out as fluoride ions, and so we do need a little bit of fluoride, but you don't want too much fluoride.
Dina Rasor:What do you do with that leftover, the leftover waste? I mean, are you able to dump it in a landfill, or are you able to? That's exactly right. Yeah, it's so captured and it's so benign. It doesn't matter if you dump it in my garden.
Dr. Michael S. Wong:Calcium fluoride is the most, is the safest version of fluoride you can have.
Dina Rasor:Okay. Yep. Wow. And then
Dr. Michael S. Wong:the, and then the LDH, once you pull out and burn off the, the P fast, now you have this LDH that can start over, and then you can reuse it, and that's kind of the nice strategy that that that the LDH that we make can can be very helpful for sustainable use of this technology, so
Greg Williams:and can that process all take place within a process water processing plan, or does it have to be taken off site and recharged elsewhere.
Dr. Michael S. Wong:Yeah, so the LDH is basically a powder, although you can probably make granules out of it. And the idea that we have, one idea anyway, is to instead of using activated carbon, you know, replace the activated carbon with the LDH, just drop it in there, it'll soak it up. And you can do one of two things, you can take out the LDH, just like you would do with the activated carbon, and hire someone just to replace it, so you can hire that same person to replace it and to regenerate it, or if you, if you are your own company, or you can afford it, or you're building a new plant, you can say, all right, I'm just going to go ahead and replace it and regenerate it on site, so you do have to have a way to knock out the PFOA inside the LDH for sure, but you can have someone else do it, or you could do it by yourself, and those are the two options there.
Greg Williams:Gotcha.
Dina Rasor:Okay, now that, so now we know what it looks like in the lab, we know what we think it's going to do, going to be there's a lot of going to bes in this world. How far away from this is this technology being employed from actual municipal water treatment plants, or whatever kind of purification you want to do, where you know, how do you scale it up? I'd say
Dr. Michael S. Wong:it's one of the big, big questions that we're asking. We've been asking ourselves ever since we got this paper, you know, accepted and published in open literature, and the answer is the following, which is we know that we can make the LDH materials very easily, so that's not a bottleneck in our system. We know how to design the system to soak out the PF to PFAs to the concentration to the effluent targets that we would want, it really depends on who, what the use case is. I think the key question is, who's going to, or the cost again, who's going to want to trial it out, because we would need to demo it, and then figure out what is the right size for the target flow rate and the treatment targets, so there's a couple of stages there, and so there are a lot of what ifs and to be dones, but there is a path to take the technology readiness of this idea from what I would sort of numerically call a two TRL four to the eventual target of technology readiness level of nine, which is TRL nine. TRL nine is when everything's fully validated. It can work in real waters, and it's something that you can buy off the shelf at the TRL nine stage. We are, I would say, we are at TRL four stage. We shown that it works under flow, under slow flow rates, under several types of water influence conditions, but to kind of bridge this sort of development gap, this valley of depth that people like to talk about, we have to go, we have to biggie sizes reactor, basically.
Greg Williams:And so, how long did it take you to get from level one to level four?
Dr. Michael S. Wong:Let's say my postdoc, who is a graduate student, started this work about four years ago, five years ago, its owner, the order of a couple of years, actually. So, I would say, yeah, so from TRL one to TRL four, it was slow goings, but the short answer is, he started this work about four years ago, I mean, plus, minus, and, but I would say four years to go from TRL one to four, and I would say, and we have some patents on this now. Now we know where to go. Now we know that the material does work so well. The engineering, not to say it's easy, but we know what to do. We know how to size it up. We know the water quality generally that it can handle, and so those who have a particular, you know, we're going to have different user users for this type of technology, and so you might be asking me, you know, and I'm asking myself, do we make a small reactor or small unit or a big unit? Are we treating one gallon a day? Are we treating a million gallons a day? I think the answer is going to be, it really depends on whoever is interested in this tech to work. Yeah,
Dina Rasor:well, the commercialization path is to get going on this, but then one of the things that we talk about is a large scale, but what could you actually also have this be in your house? How I mean, if it's not, if there's not the will to go out there in some states and filtrate it like they should, then maybe people who care about this stuff can go and buy, you know, the your version of a Brita filter, so is that, is that possible? Absolutely, you think that would be a simple thing to do, rather than trying to scale it up to a massive commercialization plant.
Dr. Michael S. Wong:Oh, absolutely. In fact, it's.. I would say it's easier. It's easier to build a smaller reactor than a big reactor. Absolutely. I think the question would then become. Um, well, you know, how do we design a little unit, basically, that just a regular person can use, right? So I'm a chemical engineer, I know how to think about it, but for just my own parents, you know, I think all they want to do is just to not even push a button, these want to open up the faucet and then out comes clean water, so the technology is there, we just have to size it properly. The open question would be, well, how do we reuse that LDH once it's soaked up and pulled in all of this PFOA? How do we take out the PFOA out of the out of the LDH, and so we can design a unit that goes right into the underneath the sink, maybe on top of this, you know, faucet exit there, and but the technology can be scaled down as well as scaled up, scaled down, I think would be pretty cool, actually, because then you don't have to worry about paying 10s of hundreds of$1,000 to create something for a centralized water treatment system, you know? You may go to Target or something like that, or a convenience store, and just buy a little thing screwed onto your faucet, and and then give it a go. So, I think the ideas will work really nicely, so we just got to
Dina Rasor:do it. I live in California, and we'd like to do things first, as you probably know from your time in California, and so I'm thinking, and because we're so big, sanely big, fourth largest economy in the world, we can sometimes do our own. So I could see something where somebody in California was people in California, are highly aware of the pollution, and there's a lot of military bases, and a lot of that kind of stuff. So, I could see somebody being an entrepreneur saying, you know, let's start making it available for California water systems that are already concerned about, because water is really important, so I'm always pushing California because we usually get, we usually go first when, when the, if the, if the federal government doesn't want to do something, then we tend to do it anyway, and the technology, so that's that's really fascinating, that you, that it can be designed up and down, because I know that's hard to do.
Dr. Michael S. Wong:Yeah, that's right. It's what's interesting is that the it all starts with the material, it starts with the sort of the chemistry problem, and it goes back to the motivation. Is how do you remove something that looks like a surfactant that really doesn't like to stick to things, but yet it does stick to things, but it does like to be in water too. How do you deal with that chemistry of this really otherwise strange molecule, it's not a natural molecule, and so, but once you sort of, you know, put on the chemist hat, I like to think of it, and I always tell my students, think like a molecule, you know, how do you pull in and capture it? Well, take advantage of the of the what I call the head group, the part of the molecule that's charged, then use something that can pull that charge, and LDH just happens to work out really well, and so if you treat it like a, like a, like an expandable sponge, and so lots of fun stuff.
Dina Rasor:Well, let's let's go from the micro to the macro now, and now say, How much of this PFAS problem, could you think realistically could be solved here? I mean, obviously they're not going to be able to filtrate the whole ocean, but as far as is groundwater and water we use and crops and everything else, I mean the amount of water that we have. How much do you think? What is your anticipation? How large it could scale up?
Dr. Michael S. Wong:Yeah, I think it goes to the question of what's the right use case of any PFAS removal technology. PFAS is everywhere, it's in our waters, and so it's in our soils, and it's in the biosolids and fertilizer. As mentioned earlier, this technology wouldn't be good for biosolids, for example. Okay, fine. We know that there's other things that you can do, but I'd say for LDH-based technologies, I think it is most appropriate for waters. Fine. The question is, what type of waters? And I think that what we've seen so far is it would be very good for drinking water. Could it be good for wastewater? I think it can be. There might be alternatives that might be just as good, but it's an open question. I say open because we don't have the data to support that. Oh, you know, this is like 10 times better than what's out there now. I think for another source of PFAs that, that's in water, and we're not going to use this in, you know, to clean river water, for example. It doesn't, doesn't match scale, the scale has to match the, the intended, you know, throughput, and so, but we can scale up, but the problem is, if you scale up, it just costs. More money, right. And so the economics, you just, you have to balance that out at the systems level. Here, I think that one thing that that could be very interesting is that for for communities that draw water, that I would say, well, you know, water stretched, and that are not located next to natural water systems, like inland, if you are in Arizona, if you are New Mexico, maybe you're next to the ocean. Actually, you know, desalination is one thing that people have talked about to generate drinking water, but that's expensive, of course. And there's only a few desal plants in the US, many around, and the rest of the world, there. What happens if, if you're, if your ocean water, you know, contains speed fast, which it does. What happens if you do diesel on some, some inland waters to take out the salt, so you can use it? You know, what do you do with that waste that comes out of these desal plants? That waste is actually very, very salty water that may or may not contain contaminants, but there are some indications that there's brackish waters out there, salty waters that contain PFAs. So, I think there's an opportunity to treat and to take out PFAs in salty waters, and I think that's a, that's a very exciting direction that I think LDH could play a role in, but if not, you know, it's good, it'll be good science papers, but if it does work, that could be another way to open up, you know, you know, new water sources that doesn't have PFAs, so it's a fun time to be a scientist, I think.
Dina Rasor:Go ahead, Greg.
Greg Williams:So, where do you think PFAS cleanup research goes from here? What, what are the next things? What are you working on now? What do you anticipate working on in the future?
Dr. Michael S. Wong:Yeah, PFAS is everywhere. I mean that, that goes without saying. I think we're making headway in terms of figuring out and laying out, I would say, strategy to take out PFS from the environment, and our approach is to take it out destructively at low cost, meaning instead of trying to just soak it out and then throwing away the activity carbon, for example, what we're doing with the LDH is sort of a step in the direction of, can we soak it out and then destroy in this form, you know, that costs less energy and reuse the material. Fine, I think there's another step where if you can destroy PFAS where it sits, where it lies directly in the water, that way then you don't have to do this absorption concentration and then destroy, so destroying PFAS using low temperature, low energy techniques directly in the water is, I think, a very interesting way
Dina Rasor:to go.
Dr. Michael S. Wong:Yeah, I, so I think that opens up, you know, use cases as well. So then that would say that's something that we're working on really hard in our group, as well as others around the world. It's not just a US issue here, but in my group, and specifically, you know, anything that can break that CF bond, and there's a lot of things that can break the CF bond. It's one of the hardest ones to break, but we know how to break it. Actually, it's just about the cost, you know, but it's also about other things in the water that could get in the way of that energy that, instead of going into that CF bond, it goes to other things we don't want that to happen. So, how do you focus all that energy into that CF bond? If you can do that, then then you, you're on your path to a more economical, more efficient way of destroying PFAs at the source of where you find the PFAs, and so we're using electrochemistry, we're using, we're using electricity to break down P fasts, we're using light to break down PFAs, we're using plasma to break down PFAs. Yeah, we're using, we're throwing everything in the kitchen sink to break down the P, the CF bond. Not everything works out, and that's completely fine, but we're identifying certain things that shows really good promise to at scale treatment. So I go back to the idea of like at the beginning, I'm an engineer, I'm a scientist, I love to figure out new tricks to break that CF bond, but I'm also an engineer enough to say, I want to solve the problem. That's why I got into this whole PFAS business, you know, just trying to clean up water, so that it becomes safer for my kids, for the next generation, so that we can make an impact, you know, in a positive direction. You know, we use PFAS for all these decades, and we didn't know how bad it was until it had. Happens. Well, I think it's our job as scientists and engineers to kind of correct ourselves, figure out ways to not use PFAS for sure, but come up with ways to take out the PFAS that's already in the environment in a cost-efficient way. And so, are things happening in my group? Yeah, I'm excited about what we can do with lights, with electricity, with plasma, and combinations between those things.
Greg Williams:Well, that's all really exciting. Is there anything that that you want to make sure we cover tonight that we haven't covered already?
Dr. Michael S. Wong:No, I can go on. I mean, how much time do I have? Except I do have to. My little one will be a little upset with me. Yeah, no, I mean, I think that the PFAs problem, when I, when I give talks about PFAS treatment technologies, I say this thing. Also, I say I hate PFAS, but I love PFAS, PFAS, because it's bad for us, but PFAS presents kind of an intellectual challenge for all of us to focus collectively, collaboratively to bring our skill set to do something that everyone you know uniformly is worried about, and right now everyone's worried about PFAS, as they should, and let's continue to really bring attention to this PFAS problem, and let's continue to hope that people recognize the PFAS problem is prevalent, it's not just in certain parts of the country or certain parts of the world, it's everywhere, just people are still slowly coming to that realization, but not everyone is equally understanding of just how prevalent this problem is, and, and hopefully you know, as the word gets out there, that we make our headway to come up with technologies that are not just great science papers, but to actually treat the waters, you know, and so I'm trying to develop the technologies in my lab as much as I can, and then hand off to folks who can try to find the right partners, and it's going to be all hands on deck in that sense.
Dina Rasor:Will you come back when you do make your next big breakthrough for us?
Dr. Michael S. Wong:If you invite me back, absolutely
Dina Rasor:consider it an open invitation.
Dr. Michael S. Wong:Appreciate it. Yeah,
Greg Williams:let us know each time you cross one of those maturity levels, so maybe we'll next talk to you when you get to five.
Dr. Michael S. Wong:Well, I really appreciate the discussion and appreciate your interest in PFAs in general, and and really enjoyed speaking with you, and and we'll talk again whenever I come up with something even bigger and better, and hopefully even more, more successful.
Greg Williams:Oh, fantastic. Well, thank you very much.
Dina Rasor:Thank.
