This inspirational and interesting episode features Dr. Wendy Lee Queen who is an American expat now working and playing baseball in Switzerland. We learn about the importance of Wendy’s early career mentors, her passion for sports and competition, and her amazing work of creating and using composite materials to capture pollutants and reclaim precious resources. You’ll learn about metal organic frameworks (MOFs), how they’re created, the variation they can have, and their potential to help address some challenges faced by industry and the environment. This episode is an out of the park home run!
Visit https://thermofisher.com/bctl to register for your free Bringing Chemistry to Life T-shirt and https://www.alfa.com/en/chemistry-podcasts/ to access our episode summary sheet, which contains links to recent publications and additional content recommendations for our guest.
Every day, tons of potentially valuable materials are discarded in various waste streams simply because recycling them is more expensive than their recoverable value. Considering that finite resources such as precious metals are among these wastes, the opportunity appears obvious.
Wendy Lee Queen, and American expat and passionate baseball player, leads the Laboratory for Functional Inorganic Materials at the EPFL in Lausanne, and has a potential solution. She is one of the leading experts of metal organic frameworks (MOF) and a pioneer of novel composite materials where MOFs and polymers in bead form provide an innovative way to fine tune affinity and selectivity for various chemical species of interest. These can be used to efficiently capture pollutants such as carbon dioxide, but also to recover valuable resources from water waste streams, such as precious metals.
Wendy’s research is a beautiful story of chemical innovation, where ground-breaking chemistry makes new things possible. And when these new things have the potential to change the way we look at our urban and industrial wastes, this is a moment chemistry is brought to life.
Dr. Wendy Lee Queen 00:06
Action is the event that inspires you to do more and more. Just do one thing, you'll be able to move on and do the second thing. And then before you know it, you've made a strong impact.
Paolo 00:18
At first, Dr. Wendy Lee Queen didn't think she was cut out for graduate school. But with a great mentor in her corner, she found out that she was. Now she's emerged as a leader in the field of metal organic frameworks that she uses as revolutionary high-performance materials that can be used to clean our air and water. In this season two episode of Bringing Chemistry to Life, we speak with another member of Chemical and Engineering News' 2020 Talented 12 about their work and trends in their field. I'm your host, Dr. Paolo Braiuca from Thermo Fisher Scientific. We began by asking Dr. Queen about how her professional journey into science began.
Dr. Wendy Lee Queen 01:00
I came from a family that was relatively uneducated. They didn't have opportunities to go to college and things like that. Most of my family worked in a local textile mill. And so I wasn't really exposed to family members and things that had college degrees. And so I was really inspired, I should tell you, kind of from the beginning, I was inspired to go to graduate school by a professor, my fourth year of college, actually. So I was doing a very small research project. And he came into the lab one day, and he said, "Wendy, where are you going graduate school?" And I said, "I'm not cut out for graduate school. I'm not even considering this." And he sat down, he, he looked at me, and he said, "Listen, if I went to graduate school, and made it through," he said, "you're going to do amazing." So he actually went into his office, and he printed my first application. And he brought it in, and he said, "By next week, you should have filled this out." And it was an application to a university that I didn't apply to. But I did apply to one of the local universities for graduate school. And I'll tell you that this is really when doors began to open for me, and I began to see really how I could use my skill set, my chemistry, to solve problems. I haven't done the same things, scientifically, throughout my career. You can say that my skill set is quite broad. The things that I'm doing now, for instance, are not the things I was doing as a graduate student.
Paolo 02:18
Did you at some point, realize that what you're doing that moment was what you wanted to do? Or again, it was just more about the opportunities took you there?
Dr. Wendy Lee Queen 02:28
The opportunities definitely took me there, for sure. I think that doors just open and I end up walking through them. I'll tell you that the biggest step for me was really in going going to graduate school. From there, I've had somewhat of a plan. So in in graduate school, for instance, I knew that I wanted to get more expertise in terms of materials characterization. And so this led me to NIST Center for Neutron Research where I began using neutrons to study the properties of materials. And then while at NIST, I got introduced to these beautiful porous materials, which I fell in love with based on their beautiful structures. And this led me to my next step, and that is really designing and synthesizing these materials, and then employing them for various applications and in separations. And so my path hasn't been very well planned out by any means.
Paolo 03:23
Do you think now, you are where you are and you're going to stick to it? Or do you think there will be more jumps going forward?
Dr. Wendy Lee Queen 03:30
I really love where I am right now. Being a professor and having the ability to run my own research team and direct a laboratory is just a really wonderful experience. You know, I get to plan new projects all the time. And I constantly get to, from this position, I get to constantly expand my own skill set and knowledge base. And one thing that I found that is extremely important for me, is, you know, hiring a very diverse team. And so I've told you that my skill set basically has expanded throughout my career. I haven't stuck to doing the same thing throughout my career. And I prefer to work with scientists that also have done, you know, things similar to me in the sense that they have a broad background because those people are not scared to get outside of their comfort zone and do new things. And I find that with different skill sets and having people that have have different knowledge bases, you really can do some very interesting creative things this way.
Paolo 04:36
Do you ever think this is risky, though?
Dr. Wendy Lee Queen 04:38
Of course, but science is risky in general. If it's not risky, then you're not probably doing something that's important. Because I mean, I tell my students all the time if it were easy, it would have already been done. This is what we're here to do is is work through big problems.
Paolo 04:53
Makes a lot of sense. And and now we're gonna get we're gonna get into the science but before getting there. I have one question. I was really intrigued, you know, reading your resume and, and understanding a bit more about you, about your interest in sports and baseball, in particular. So, has this anything to do with your career is that do do you think sports has given you something?
Dr. Wendy Lee Queen 05:15
Well, for sure. I mean, sports gave me an education. Up through college, I played fastpitch softball, and paid for my education this way. And then I took a break for many years. And now that I'm in Switzerland, I started playing in the Swiss baseball league. So I'm ending where I started back in baseball, mostly playing with men. I really enjoy competition. And I think the the competition you see in sports is comparable, for instance, to the competition that you might experience, for instance, in science. But it's also instilled a strong sense of team and the importance of team, I think, in my mind. And this is a direct, directly correlated kinda with how I tend to run my lab as well. I tell the students that nothing that's worth achieving can be done alone, right? It requires a team effort. So to solve large scale problems, this these types of things cannot be done individually. And so I think that there is a direct correlation between sports, competition, teamwork with, you know, lab work and research.
Paolo 06:29
Let's start having a look into this teamwork and how, you know, it relates into research and the results you've had in your, in your last few years.
Dr. Wendy Lee Queen 06:41
So our group is focused on the design of a relatively new class of materials referred to as metal organic frameworks. These materials consist of building blocks, the building blocks are metals or metal ions. And the second set of building blocks are organic iso- ligands, essentially, what we do is we mix these two building blocks in solution. We might heat that solution up, the building blocks stick together, and they form these really, highly porous materials, their pores are about 50,000 times smaller than than the diameter of human hair. And as chemists, basically what we do is we functionalize the inside of these materials in a special way, so that we can use them to selectively grab certain, for instance, contaminants or targeted species. So our group is really specialized in separations, we do the separations in liquids, we also do the separations in gases. So for instance, some some really important separations today are, of course, carbon dioxide capture. And of course, we know that global warming, CO2, high atmospheric CO2 levels are implicated in global warming. And so we're trying to selectively grab that carbon dioxide from different gas streams. For instance, like air or exhaust gas. And of course, water purification is a liquid based separation, which is, of course, extremely important to humanity. Because clean water is required to sustain human life.
Paolo 08:12
Let's speak a little bit about this metal organic frameworks and their structure. So you mentioned there's, there's basically, they're made of a couple of different types of monomers, you have a metal or metal ion, and there's a coordination with some organic compounds. First of all, what kinds of metals are typically used for those structures, and why?
Dr. Wendy Lee Queen 08:34
You can use a wide variety of different types of metals. Predominantly, we work with lighter third row transition metals. There, basically we try to work with with metals that are more abundant, so to speak so, and cheap. Because you can imagine, depending on your application, if you have a really large scale application, you can't use a really expensive metal that's rare. So we try to focus on things like iron, aluminum, you know, magnesium base building blocks.
Paolo 09:04
And what kind of organic building blocks are common in these structures? I suppose there's a lot of diversity there.
Dr. Wendy Lee Queen 09:10
Yeah, there there is a lot of diversity, but you have to be careful with the organic base building blocks that you select. So, you can imagine the various types, of course, are things like carboxylates, pyrazolates, triazolates, things of that sort. The building block that you select, of course, you want it to combine with the metal in such a way that it gives rise to a material that that is highly stable for your given application. So you need a certain level of interaction between your metal and your your organic building block, your ligand, that we call it. So it requires a lot of knowledge in terms of the building blocks that you select for a given application, so to speak, if that makes sense.
Paolo 09:55
What about those synthesis? Is it something difficult to control? Or do these materials tend to interact and self-assemble in a relatively simple way?
Dr. Wendy Lee Queen 10:03
They tend to self-assemble in a relatively simple way. Like I said, we, we really just mix these building blocks typically in solution, you simply heat those solutions. Now finding the right solution to put in, it can be tricky, of course. I mean, you can screen you know, 1000 reactions just to find one material, just because you have to find the right liquid, the right solvent to put it in. Also, you have to find the right building block combinations. Because if your material is not stable, it might be that you make it but then you pull it out of a solution and it, it just collapses, right? It's tricky in that sense, selecting the right combinations of things. But once you have that, of course, it readily self assembles, so to speak. Also, I should say that probably, with regard to metal organic framework chemistry, one of the difficult parts is the actual organic base building blocks. So there are a few of those, for instance, that are commercially available. But when you want to expand the pore size and things, oftentimes we want larger or longer organic building units. And so then you might have to use some quite complicated organic base chemistry in order to devise these building blocks for your metal organic framework.
Paolo 11:15
Is the porosity, which seems to be the key characteristic, right, of the structures, intrinsically depending on the monomers you use? Or is there an effect of the synthetic approach to them? So is there a way to control porosity via reaction conditions, rather than simply the nature of the building blocks you're using?
Dr. Wendy Lee Queen 11:41
Yes, because there are a lot of different approaches to make one single MOF, for instance. And the key is, is that you might use two different synthetic approaches that give you a different level of porosity. So yes, indeed, for instance, the solvent environment that you use can influence how porous a given material is. Although those materials have the same exact structure, right. So it is it is very, very tricky in that sense.
Paolo 12:12
But porosity, per se, is probably not not enough to capture selectively, you know, one one compound, one compound or the other. You know, if you're looking for affinity for for carbon dioxide, or if you're looking for trying to extract, I don't know, some metal ions from from a water stream, you're probably you're probably looking at completely different functionalizations. So how do you take all these sorts of things? And how does the functionalization affect actually the structure of the metal organic framework itself?
Dr. Wendy Lee Queen 12:45
Well, I would tell you that that that really depends on the approach that you take to functionalize the metal organic framework, and and there are many different ways. You can functionalize the organic ligand, right? Or you could insert something, after you make the MOF, you could post synthetically insert something. And so if that's the case, you're not really going to change the structure very much at all, it's just that you're putting some other guests species inside it's interacting with the surface, that then controls how that material kind of interacts with the external environment, so to speak, whether it be carbon dioxide or a heavy metal. And so that's really what my group is specializing in is we're post synthetically modifying our MOF, typically, so we make our MOF's in solution. And then we go in and we find other approaches to then post synthetically graft things to the ligand, or more commonly, we actually insert polymers inside the material. So we use these as like a nano reactor and we put monomers inside we grow polymeric chains directly inside the MOF, the MOF itself. And so this can can give rise it can to significantly improved properties. So it can increase your capacities for whatever target that you want, and selectivity as well. You can imagine in separation selectivity is extremely important.
Paolo 14:05
Is this your way of trying to meet that sort of structural characteristics of the of the MO's, of the MOF's? So their high porosity with the polymer characteristics of chemical affinity for whatever you're trying to capture?
Dr. Wendy Lee Queen 14:21
That's exactly right. So it's not so easy just to make highly porous polymers. You know, polymer chains kind of intertwine and they readily collapse. There's nothing that kind of pins those open. Whereas MOF's are naturally porous materials. And so you can kind of think of it as the modifications that we're doing, we're kind of trying to introduce extrinsic porosity to polymers that are not really intrinsically porous, right. So now, because we put it kind of inside that MOF, you can imagine now the the nice functionality on that polymer backbone is readily accessible by whatever guest species we want to put inside. And so relative to the bulk polymers our MOF polymer composite actually can offer a lot higher capacities and things, right. Because you can access the polymer now.
Paolo 14:21
What is the chemical interaction between the polymer and the MOF?
Dr. Wendy Lee Queen 15:12
I should describe it as like a ship in the bottle approach. So we try to put our monomers in our MOF, then our MOF catalyzes the polymerization process, and so the polymers grow, and then I just get stuck inside. So you can also have certain sites inside of your MOF like metals, sometimes the metals are accessible. And if you have like a Lewis base functionality like a nitrogen, it can bond to the metal. And so that can give you a really strong kind of coordination between the MOF and the polymer you can have electrostatic interactions. It's really interesting in MOF chemistry, because what people are finding when when we insert polymers into MOFs, they are really altering the the properties of the MOF. So we find some interesting effects. For instance, we found that it improves the mechanical stability of large MOFs that can actually inhibit them from collapsing. So materials that that when you pull them out, they have the the mother liquor which you synthesize in when they collapse, you can insert a polymer beforehand, and it will inhibit that material from collapsing. So you can now access MOFs that you can't you couldn't access before. Also, we find that they can significantly improve the MOF stability. So in various chemical environments, for instance, some MOFs are unstable in human environments. And we find that a lot of times the polymers can significantly change the material stability in various chemical environments, like in humidity, or acids, and bases even. So this chemistry is really interesting. And so I'm really excited to see how these things unfold as we begin to understand why the polymers improving the stability of the MOF so much.
Paolo 16:59
That can see why this is exciting. What kind of molecular weight you can achieve with with a MOFs and is, is is the polymer somehow linking several MOFs units is to make sort of more sizable bead kind of material? So I'm thinking about potential practical applications on you how you handle the finished product here.
Dr. Wendy Lee Queen 17:21
Indeed, we do have to form these fine particles into beads. So this is actually a second way that we use polymers. So for the first approach, we basically insert our, our monomers into our MOFs and grow the polymer chains inside this is to enhance the MOF capacity and performance and in our given application, then subsequently, we use another strategy to form polymers on the external surface to bind the particles together to form different structures for actual separation units. And this is what we're having to do as we're studying our materials and more application relevant environments under basically continuous flow, like continuous water flow, for instance.
Paolo 18:02
How do you control the fact that particularly in remediation application, very often the waste streams are highly uncontrolled? So it's very hard to predict the kinds of conditions you will, you know, subject your material into.
Dr. Wendy Lee Queen 18:16
Yeah, I'll tell you that this has really been a very tough situation. For water purification, it's not so bad. Typically, we find that when we make materials, they're highly selective. In groundwater, they're highly selective, whether it be tap water, whether it be ocean water, everything is good. Where we really run into a lot of problems is when we deal with industrial waste. And the reason is because various industries use many different processes. And because of that, the waste streams that they generate, are really different across the board. And so what I'll tell you is that we just have to test our materials in the different the different waste streams, but we're beginning to learn. For instance, we have a project that we've been focused on the extraction of precious metals from electronic waste, as well as industrial wastes. So we're extracting things like gold. And you can imagine if you go to a jewelry producer, you know, maybe they produce watches or necklaces, and then you go to an actual precious metal refinery. You can imagine that these waste streams vary quite significantly. And so we're learning what types of environments that we can we can work in and once they tell us their processes, we know whether we can work in it or not, for instance.
Paolo 19:35
What's the general level of robustness though in in in the material? Do you think it is going to be relatively easily achievable, or sort of strong enough stability to you know, be be confident the material is going to be stable to sort of wide range of conditions or do you think this is going to be like one of the biggest challenge in your development?
Dr. Wendy Lee Queen 19:58
It depends on the MOF. And it also depends on the polymer combination. So there are ways to make these materials quite stable. But also there are some materials that aren't. And so this, I would tell you, is the really tricky part about jumping into the MOF field is because it takes a lot of experience, kind of, to know the ins and outs of the chemistry so to speak.
Paolo 20:28
We hope you're among the 1000s of listeners enjoying Bringing Chemistry to Life. It would really mean a lot to us if you help give visibility to the great science of our guests, just by sharing the podcast with a couple of friends or colleagues. If you want to know more about Wendy and her work, stay tuned at the end of the episode for information on how to access content recommendations from her, as well as information on how to register for a free Bringing Chemistry to Life T-shirt. And now back to our conversation.
I like to go a little bit into the these applications. So you mentioned a couple of things that are very interesting, you know, capturing carbon dioxide, for instance, from from from air, or treating industrial streams to try and extract selectively I suppose precious metals. Can you go a little bit more into the chemistry or what what kind of mechanisms you leverage for some of your most relevant applications?
Dr. Wendy Lee Queen 21:23
So just to give you an example, carbon dioxide captures. So if you look, for instance, at a coal fired power plant. So you can imagine they're burning these carbon based fuels, they produce a flue gas and that flue gas, there are lots of small molecules. The key is is that we look at the target that we want to obtain, and that is carbon dioxide. Carbon dioxide is known to have, it basically has selective interactions with amines. So you can form for instance, species like carbamates. And so if we functionalized the inside of our MOFs with polymers, for instance, that have amines we can significantly boost the MOFs capacity and selectivity, for instance, for CO2 over the main component in flue gas, which is nitrogen. And so these are the types of things that we're using. For gold, we've done something very different that I haven't seen, our material doesn't just bond gold, our polymer is actually redox active, and in the process, that it binds the gold, it reduces the gold into its metallic state. And so this combined absorption and redox base chemistry is what really gives rise to our higher capacities that we see. So we can put our material for instance, in a very low concentrated solution. And it just absorbs all of the gold because as it absorbs it, it's also reducing it into its metallic state. And so we play on different physical and chemical properties of whatever our target is. And so we design our material around our target. It's really fun chemistry.
Paolo 23:05
It is it is indeed fun chemistry. And there's a lot of diversity there. So there's a lot you can play with. If you started looking into the economics of this, because you know, there are alternative technologies that are not even close in terms of efficiency, but very often they are already industrialized, and they're super cheap.
Dr. Wendy Lee Queen 23:23
Exactly. We're now in this process of working to try and bring these materials to market. So one of the postdocs in my group is has recently received a grant and her project and is called Retriva. So this will be the name of the startup company that hopefully stems that that's spins out of this work. So yeah, we're currently working on assessing the the commercial aspects, and we're trying to find what areas of the market our materials are extremely beneficial relative to those of the commercial base materials that you've mentioned.
Paolo 24:01
Was cost a parameter in your investigation so far at all? Or is it just now that you started looking into that? How did you have a proof of concept?
Dr. Wendy Lee Queen 24:10
When we are looking at a given application, we're always considering costs. But for instance, the MOF that we're using is made from iron. So it's, it's relatively cheap to make. We estimate that if you buy the starting materials, at least on the ton scale, you you can buy those at about $2.50 cents per kilo. Now, of course, if it's produced, it won't be that low. But certainly if you consider the fact that one kilogram of material can concentrate up to a kilogram of gold, that's going to be really huge markup. So economically, we certainly see the benefit even if our materials are a little bit higher than than what's on the market in terms of commercially available materials. Because of the differences in performance. We believe that they can still easily stand out.
Paolo 25:00
How far do you think we are from a real commercial application?
Dr. Wendy Lee Queen 25:05
Well, there are already companies that are springing up all around the world that are based on MOF chemistry. In fact, there's a, there's a company in Switzerland called novoMOF. And they're working on making larger amounts of MOFs on the kilogram scale, and trying to help bring those to market. So they're supplying various industries, metal organic frameworks. There's also a company just outside of Chicago. And they already have an edge in in their market. They're basically using MOFs for the storage of toxic gases and their delivery also. And so there are commercial applications popping up for MOFs, or I have no idea how many companies but there are many around the world at this point, there's one that's focused on the capture of water from from air. So for instance, devices that can deliver water to remote regions of the world. I think there's another that's focused on for instance, like natural gas storage, and there are many different interesting applications. There's one that's focused on sensing, they're using MOFs.
Paolo 26:17
This is this is exciting, because it's developed enough to be real, right? And so you can you can, you can feel it right? You can almost touch it. And, and there's there's this certainty that somehow this can become a real, a real thing. And so so, you know, we go back to the point that we were touching on at the very beginning of our conversation, when you will say how much the importance of your work having a real life impact is for you. Right. And so there was that that's yeah, that's, that's, that's great. I can see why you're excited. And why this this is this is very interesting. So until now, our world is really been based on this sort of linear economy, right? You take your resource, you use it, you waste it, and you forget about it. What you're trying to do here with these applications, and and there are other technologies as well, using two is trying to go towards the sort of circular economy where value is recovered from waste. And when you try of transforming waste into a new resource, right. We reput it into into the economic circle. But, you know, if I look, if I look outside, I don't think we really are close to a backdrop proper circular economy, what are your thoughts? You know. Will this ever happen?
Dr. Wendy Lee Queen 27:37
I hope so. I really hope so. I mean, achieving a completely circular economy is not not an easy thing, for sure. But I think, really, at the end of the day, probably the the difficulty associated with this has to do with economics, right. And so it's a matter of how costly it is, most most companies and things are very interested in making a profit. And so I think that this is really where politics and policy come into play. Because we have to be willing to, to take potentially a financial cut in some regard in order to implement some of these technologies. I mean, if we look at carbon dioxide capture, this is a really important one we all agree that CO2 is, is causing major problems in our world. The problem is, is that there are technologies out there that can capture carbon dioxide, right, but they're not implemented. And the problem is, is that if you implement these technologies, they decrease the efficiency of, for instance, the power plants. And so you can imagine that, that this creates problems. And also, if you consider carbon dioxide, the scale of it, it's huge. And so it's going to be financially costly for these plants to be modified, and the technology to be implemented. So this is where I think, really policy and things play a significant role. And this is why it's so important for the general public, to kind of have an idea about what the problems are, because it it will impact the the people that we put into office, which can can help us change things over time.
Paolo 29:20
And I will say we need more people like yourself, pushing the envelope and looking into potential new technologies that can actually make it economically feasible.
Dr. Wendy Lee Queen 29:29
Yeah, for sure. In science in general, you know, we need to keep these these sorts of things in mind, and not necessarily just do science for science sake. But But keep in mind that if we have a large scale application, we need to try and use at least, you know, Earth abundant elements and things like that in order to achieve it. Because at the end of the day, it doesn't matter how good your science is, if it can't be implemented then, you know, at some point we'll have to question was it really worthwhile? I don't know. I mean, certainly, I should say that there's a lot of good knowledge that comes from basic science. But we also have to keep these things in mind as we as we move along.
Paolo 30:08
There's a bright horizon in many ways, right? There are opportunities, and there are challenges to take. But they're also very exciting. It's also very exciting to do that. And so from a person who has such a strong influence on on the world, you know, and they're looking at your career so far. This I come to my to my usual final question is, you know, what, what would be a piece of advice you would give to a young scientist just starting their career?
Dr. Wendy Lee Queen 30:41
I would say, probably for a person that's just starting their career, you know, some of the problems that we face can can seem very overwhelming. And I think that maybe a lot of people look at these problems and are a bit discouraged because they don't know where to start. But I would say that for a young person starting out, just do something. Because action is the event that inspires you to do more and more. Just do one thing. You'll be able to move on and do the second thing, and then before you know it, you've made a strong impact. The second thing is, I think it's really important to be surrounded by supportive mentors. You know, if you're not in a good situation, get out of it and look for the right mentors from the beginning because they can really give you guidance and help you open doors.
Paolo 31:44
That was Dr. Wendy Lee Queen, Associate Professor of Chemical Engineering at the Swiss Federal Institute of Technology in Lausanne, and one of the Chemical and Engineering News' Talented 12. Thanks for joining us for the season two episode of Bringing Chemistry to Life and keep an ear out for more. If you enjoyed this conversation, you're sure to enjoy Dr. Queen's book, video podcasts and other content recommendations. Look in the episode notes for a URL where you can access these recommendations or register for a free Bringing Chemistry to Life T-shirt. This URL is thermofisher.com/BCTL. This episode was produced by Matt Ferris, Matthew Stock and Emma-Jean Weinstein.