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      in Environment

      Volunteer committee helps the MIT community live and work sustainably

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      April 22 marks the arrival of Earth Day, which provides all of us with a good reason to think of ways to live more sustainably. For more than 20 years, the MIT Working Green Committee has helped community members do just that by encouraging the reuse and recycling of possessions.

      Made up entirely of volunteers, the committee has played an important role in promoting more sustainable operations at MIT and raising awareness of the importance of conservation.

      “We try to provide a place for people to learn how to live and work in a more environmentally friendly way,” says committee co-chair Rebecca Fowler, a senior administrative assistant in MIT’s Office of Sustainability.

      The committee hosts regular Choose to Reuse events to give MIT’s community members a chance to donate unwanted items — or find free things that just might become prized possessions. It also provides resources to help host more sustainable events, make more sustainable purchasing decisions, and learn more about recycling.

      “The recycling industry is very frustrating, so people are always asking what to do,” Fowler says. “They feel like they make the wrong decisions and just want to know how to do it. We get a lot of questions, and we’re always there to help find answers.”

      Committee members say they’ve realized devoting a little time each month to things like recycling education, and hosting events can make a big difference in reducing waste. In last month’s Choose to Reuse event, more than 100 people dropped off thousands of items including clothing, housewares, and office supplies. MIT’s always-active Reuse email lists, which the committee encourages community members to join, are another great way to pass gently used items to others who can give them new life.

      “The goal is to keep things out of landfills, and the Choose to Reuse event shows you immediate results,” says committee co-chair Gianna Hernandez-Figueroa, who is the assistant to the director at the MIT AgeLab. “It’s inspiring because people are excited to put things in the hands of someone who is going to repurpose it. It’s a circular event that’s really beautiful.”

      Choose to Reuse events are typically on the third Thursday of every other month, although the next one — the last for the spring semester — is on Monday, April 24.

      The committee is one of the only groups on campus run by support staff, whose responsibilities involve clerical duties, data processing, and library and accounting functions, among other things. It is a subcommittee of the Working Group for Support Staff.

      The committee began as the Working Group on Recycling in 2000 at a time when MIT’s recycling rate was around 11 percent. By 2006, MIT had reached a 40 percent recycling rate and received a Go Green Award from the City of Cambridge. That year the committee earned an MIT Excellence Awards for its work.

      Around 2011, the group started hosting Choose to Reuse events, which became an instant success.

      “I really believe in the gift economy, specifically in academic settings where you have a lot of international students,” Hernandez-Figueroa says. “Plus, Boston is an expensive city!”

      For a long time, the group was run by Ruth Davis, who served as MIT’s manager for recycling and materials management and retired last year. Since Davis left, others have stepped up.

      “A lot of the volunteers have been around since the first Choose to Reuse event 13 years ago,” Fowler says, adding that the committee is always looking for more volunteers. “They’re all very committed to the event and to the cause.”

      The organization is also a way for support staff to gain new skills. Fowler credits her experience working on the committee with improving her project management and website design abilities.

      “We really emphasize capacity building,” Fowler says. “If there’s a skill a volunteer would like to develop, we can explore ways to do that through the committee. That’s something I’d like to continue: finding people’s strengths and helping them build their careers.”

      Overall, Fowler says the committee aligns with MIT’s commitment to make an impact.

      The group’s long history “shows a commitment to environmentalism and sustainability and a yearning to do more beyond what is in your job responsibilities,” she says. “It really shows the commitment to volunteerism of MIT’s staff members.” More

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      in Environment

      3 Questions: New MIT major and its role in fighting climate change

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      Launched this month, MIT’s new Bachelor of Science in climate system science and engineering is jointly offered by the departments of Civil and Environmental Engineering (CEE) and Earth, Atmospheric and Planetary Sciences (EAPS). As part of MIT’s commitment to aid the global response to climate change, the new degree program is designed to train the next generation of leaders, providing a foundational understanding of both the Earth system and engineering principles — as well as an understanding of human and institutional behavior as it relates to the climate challenge. Jadbabaie and Van der Hilst discuss the new Course 1-12 multidisciplinary major and why it’s needed now at MIT. 

      Q: What was the idea behind launching this new major at MIT?

      Jadbabaie: Climate change is an incredibly important issue that we must address, and time is of the essence. MIT is in a unique position to play a leadership role in this effort. We not only have the ability to advance the science of climate change and deepen our understanding of the climate system, but also to develop innovative engineering solutions for sustainability that can help us meet the climate goals set forth in the Paris Agreement. It is important that our educational approach also incorporates other aspects of this cross-cutting issue, ranging from climate justice, policy, to economics, and MIT is the perfect place to make this happen. With Course 1’s focus on sustainability across scales, from the nano to the global scale, and with Course 12 studying Earth system science in general, it was a natural fit for CEE and EAPS to tackle this challenge together. It is my belief that we can leverage our collective expertise and resources to make meaningful progress. There has never been a more crucial time for us to advance students’ understanding of both climate science and engineering, as well as their understanding of the societal implications of climate risk.

      Van der Hilst: Climate change is a global issue, and the solutions we urgently need for building a net-zero future must consider how everything is connected. The Earth’s climate is a complex web of cause and effect between the oceans, atmosphere, ecosystems, and processes that shape the surface and environmental systems of the planet. To truly understand climate risks, we need to understand the fundamental science that governs these interconnected systems — and we need to consider the ways that human activity influences their behavior. The types of large-scale engineering projects that we need to secure a sustainable future must take into consideration the Earth system itself. A systems approach to modeling is crucial if we are to succeed at inventing, designing, and implementing solutions that can reduce greenhouse gas emissions, build climate resilience, and mitigate the inevitable climate-related natural disasters that we’ll face. That’s why our two departments are collaborating on a degree program that equips students with foundational climate science knowledge alongside fundamental engineering principles in order to catalyze the innovation we’ll need to meet the world’s 2050 goals.

      Q: How is MIT uniquely positioned to lead undergraduate education in climate system science and engineering? 

      Jadbabaie: It’s a great example of how MIT is taking a leadership role and multidisciplinary approach to tackling climate change by combining engineering and climate system science in one undergraduate major. The program leverages MIT’s academic strengths, focusing on teaching hard analytical and computational skills while also providing a curriculum that includes courses in a wide range of topics, from climate economics and policy to ethics, climate justice, and even climate literature, to help students develop an understanding of the political and social issues that are tied to climate change. Given the strong ties between courses 1 and 12, we want the students in the program to be full members of both departments, as well as both the School of Engineering and the School of Science. And, being MIT, there is no shortage of opportunities for undergraduate research and entrepreneurship — in fact, we specifically encourage students to participate in the active research of the departments. The knowledge and skills our students gain will enable them to serve the nation and the world in a meaningful way as they tackle complex global-scale environmental problems. The students at MIT are among the most passionate and driven people out there. I’m really excited to see what kind of innovations and solutions will come out of this program in the years to come. I think this undergraduate major is a fantastic step in the right direction.

      Q: What opportunities will the major provide to students for addressing climate change?

      Van der Hilst: Both industry and government are actively seeking new talent to respond to the challenges — and opportunities — posed by climate change and our need to build a sustainable future. What’s exciting is that many of the best jobs in this field call for leaders who can combine the analytical skill of a scientist with the problem-solving mindset of an engineer. That’s exactly what this new degree program at MIT aims to prepare students for — in an expanding set of careers in areas like renewable energy, civil infrastructure, risk analysis, corporate sustainability, environmental advocacy, and policymaking. But it’s not just about career opportunities. It’s also about making a real difference and safeguarding our future. It’s not too late to prevent much more damaging changes to Earth’s climate. Indeed, whether in government, industry, or academia, MIT students are future leaders — as such it is critically important that all MIT students understand the basics of climate system science and engineering along with math, physics, chemistry, and biology. The new Course 1-12 degree was designed to forge students who are passionate about protecting our planet into the next generation of leaders who can fast-track high-impact, science-based solutions to aid the global response, with an eye toward addressing some of the uneven social impacts inherent in the climate crisis. More

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      in Energy

      Moving perovskite advancements from the lab to the manufacturing floor

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      The following was issued as a joint announcement from MIT.nano and the MIT Research Laboratory for Electronics; CubicPV; Verde Technologies; Princeton University; and the University of California at San Diego.

      Tandem solar cells are made of stacked materials — such as silicon paired with perovskites — that together absorb more of the solar spectrum than single materials, resulting in a dramatic increase in efficiency. Their potential to generate significantly more power than conventional cells could make a meaningful difference in the race to combat climate change and the transition to a clean-energy future.

      However, current methods to create stable and efficient perovskite layers require time-consuming, painstaking rounds of design iteration and testing, inhibiting their development for commercial use. Today, the U.S. Department of Energy Solar Energy Technologies Office (SETO) announced that MIT has been selected to receive an $11.25 million cost-shared award to establish a new research center to address this challenge by using a co-optimization framework guided by machine learning and automation.

      A collaborative effort with lead industry participant CubicPV, solar startup Verde Technologies, and academic partners Princeton University and the University of California San Diego (UC San Diego), the center will bring together teams of researchers to support the creation of perovskite-silicon tandem solar modules that are co-designed for both stability and performance, with goals to significantly accelerate R&D and the transfer of these achievements into commercial environments.

      “Urgent challenges demand rapid action. This center will accelerate the development of tandem solar modules by bringing academia and industry into closer partnership,” says MIT professor of mechanical engineering Tonio Buonassisi, who will direct the center. “We’re grateful to the Department of Energy for supporting this powerful new model and excited to get to work.”

      Adam Lorenz, CTO of solar energy technology company CubicPV, stresses the importance of thinking about scale, alongside quality and efficiency, to accelerate the perovskite effort into the commercial environment. “Instead of chasing record efficiencies with tiny pixel-sized devices and later attempting to stabilize them, we will simultaneously target stability, reproducibility, and efficiency,” he says. “It’s a module-centric approach that creates a direct channel for R&D advancements into industry.”

      The center will be named Accelerated Co-Design of Durable, Reproducible, and Efficient Perovskite Tandems, or ADDEPT. The grant will be administered through the MIT Research Laboratory for Electronics (RLE).

      David Fenning, associate professor of nanoengineering at UC San Diego, has worked with Buonassisi on the idea of merging materials, automation, and computation, specifically in this field of artificial intelligence and solar, since 2014. Now, a central thrust of the ADDEPT project will be to deploy machine learning and robotic screening to optimize processing of perovskite-based solar materials for efficiency and durability.

      “We have already seen early indications of successful technology transfer between our UC San Diego robot PASCAL and industry,” says Fenning. “With this new center, we will bring research labs and the emerging perovskite industry together to improve reproducibility and reduce time to market.”

      “Our generation has an obligation to work collaboratively in the fight against climate change,” says Skylar Bagdon, CEO of Verde Technologies, which received the American-Made Perovskite Startup Prize. “Throughout the course of this center, Verde will do everything in our power to help this brilliant team transition lab-scale breakthroughs into the world where they can have an impact.”

      Several of the academic partners echoed the importance of the joint effort between academia and industry. Barry Rand, professor of electrical and computer engineering at the Andlinger Center for Energy and the Environment at Princeton University, pointed to the intersection of scientific knowledge and market awareness. “Understanding how chemistry affects films and interfaces will empower us to co-design for stability and performance,” he says. “The center will accelerate this use-inspired science, with close guidance from our end customers, the industry partners.”

      A critical resource for the center will be MIT.nano, a 200,000-square-foot research facility set in the heart of the campus. MIT.nano Director Vladimir Bulović, the Fariborz Maseeh (1990) Professor of Emerging Technology, says he envisions MIT.nano as a hub for industry and academic partners, facilitating technology development and transfer through shared lab space, open-access equipment, and streamlined intellectual property frameworks.

      “MIT has a history of groundbreaking innovation using perovskite materials for solar applications,” says Bulović. “We’re thrilled to help build on that history by anchoring ADDEPT at MIT.nano and working to help the nation advance the future of these promising materials.”

      MIT was selected as a part of the SETO Fiscal Year 2022 Photovoltaics (PV) funding program, an effort to reduce costs and supply chain vulnerabilities, further develop durable and recyclable solar technologies, and advance perovskite PV technologies toward commercialization. ADDEPT is one project that will tackle perovskite durability, which will extend module life. The overarching goal of these projects is to lower the levelized cost of electricity generated by PV.

      Research groups involved with the ADDEPT project at MIT include Buonassisi’s Accelerated Materials Laboratory for Sustainability (AMLS), Bulović’s Organic and Nanostructured Electronics (ONE) Lab, and the Bawendi Group led by Lester Wolfe Professor in Chemistry Moungi Bawendi. Also working on the project is Jeremiah Mwaura, research scientist in the ONE Lab. More

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      in Environment

      Podcast: Curiosity Unbounded, Episode 1 — How a free-range kid from Maine is helping green-up industrial practices

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      The Curiosity Unbounded podcast is a conversation between MIT President Sally Kornbluth and newly-tenured faculty members. President Kornbluth invites us to listen in as she dives into the research happening in MIT’s labs and in the field. Along the way, she and her guests discuss pressing issues, as well as what inspires the people running at the world’s toughest challenges at one of the most innovative institutions on the planet.

      In this episode, President Kornbluth sits down with Desirée Plata, a newly tenured associate professor of civil and environmental engineering. Her work focuses on making industrial processes more environmentally friendly, and removing methane — a key factor in global warming — from the air.

      FULL TRANSCRIPT:

      Sally Kornbluth: Hello, I’m Sally Kornbluth, president of MIT, and I’m thrilled to welcome you to this MIT community podcast, Curiosity Unbounded. In my first few months at MIT, I’ve been particularly inspired by talking with members of our faculty who recently earned tenure. Like their colleagues, they are pushing the boundaries of knowledge. Their passion and brilliance, their boundless curiosity, offer a wonderful glimpse of the future of MIT.

      Today, I’m talking with Desirée Plata, associate professor of civil and environmental engineering. Desirée’s work is focused on predicting the environmental impact of  industrial processes and translating that research to real-world technologies. She describes herself as an environmental chemist. Tell me a little more about that. What led you to this work either personally or professionally?

      Desirée Plata: I guess I always loved chemistry, but before that, I was just a kid growing up in the state of Maine. I like to describe myself as a free-range kid. I ran around and talked to the neighbors and popped into the local businesses. One thing I observed in my grandparents’ town was that there were a whole lot of sick people. Not everybody, but maybe every other house. I remember being about seven or eight years old and driving home with my mom to our apartment one day and saying, “It’s got to be something everybody shares. The water, maybe something in the food or the air.” That was really my first environmental hypothesis.

      Sally: You had curiosity unbounded even when you were a child. 

      Desirée: That’s right. I spent the next several decades trying to figure it out and ultimately discovered that there was something in the water where my grandmother lived. In that time, I had earned a chemistry degree and came to MIT to do my grad work at MIT in the Woods Hole Oceanographic in environmental chemistry and chemical oceanography.

      Sally: You saw a pattern, you thought about it, and it took some time to get the tools to actually address the questions, but eventually you were there. That is great. As I understand it, you have two distinct areas of interest. One is getting methane out of the atmosphere to mitigate climate warming, and the other is making industrial processes more environmentally sound. Do you see these two as naturally connected?

      Desirée: I’ll start by saying that when I was young and thinking about this chemical contamination that I hypothesized was there in my grandmother’s neighborhood, one of the things—when I finally found out there was a Superfund site there—one of the things I discovered was that it was owned by close family friends. They were our neighbors. The decisions that they made as part of their industrial practice were just part of standard operating procedure. That’s when it clicked for me that industry is just going along, hoping to innovate to make the world a better place. When these environmental impacts occur, it’s often because they didn’t have enough information or know the right questions to ask. I was in graduate school at the time and said, “I’m at one of the most innovative places on planet Earth. I want to go knock on the doors of other labs and say, ‘What are you making and how can I help you make it better?'”

      If we all flash back to around 2008 or so, hydraulic fracturing was really taking off in this country and there was a lot of hypotheses about the number of chemicals being used in that process. It turns out that there are many hundreds of chemicals being used in the hydraulic fracturing process. My group has done an immense amount of work to study every groundwater we could get our hands on across the Appalachian region of the eastern United States, which is where a lot of this development took place and is still taking place. One of the things we discovered was that some of the biggest environmental impacts are actually not from the injected chemicals but from the released methane that’s coming into the atmosphere. Methane is growing at an exorbitant rate and is responsible for about as much warming as CO2 over the next 10 years. I started realizing that we, as engineers and scientists, would need a way to get these emissions back. To take them back from the atmosphere, if you will. To abate methane at very dilute concentrations. That’s what led to my work in methane abatement and methane mitigation.

      Sally: Interesting. Am I wrong about when we think about the impact of agriculture on the environment, that methane is a big piece of that as well?

      Desirée: You are certainly not wrong there. If you look at anthropogenic emissions or human-derived emissions, more than half are associated with agricultural practices. The cultivation of meat and dairy in particular. Cows and sheep are what are known as enteric methane formers. Part of their digestion process actually leads to the formation of methane. It’s estimated that about 28% of the global methane cycle is associated with enteric methane formers in our agricultural practices as humans. There’s another 18% that’s associated with fossil energy extraction.

      Sally: That’s really interesting. Thinking about your work then, particularly in agriculture, part of the equation has got to be how people live, what they eat, and production of methane as part of the sustainability of agriculture. The other part then seems to be how you actually, if you will, mitigate what we’ve already bought in terms of methane in the environment.

      Desirée: Yes, this is a really important topic right now.

      Sally: Tell me a little bit about, maybe in semi-lay terms, about how you think about removal of methane from the environment.

      Desirée: Recently, over 120 countries signed something called the Global Methane Pledge, which is essentially a pledge to reduce 45% of methane emissions by 2030. If you can do that, you can save about 0.5 degree centigrade warming by 2100. That’s a full third of the 1.5 degrees that politicians speak about. We can argue about whether or not that’s really the full extent of the warming we’ll see, but the point is that methane impacts near-term warming in our lifetimes. It’s one of the unique greenhouse gases that can do that.

      It’s called a short-lived climate pollutant. What that means is that it lives in the atmosphere for about 12 years before it’s removed. That means if you take it out of the atmosphere, you’re going to have a rapid reduction in the total warming of planet Earth, the total radiative forcing. Your question more specifically was about, how do we grapple with this? We’ve already omitted so much methane. How do we think about, as technologists, getting it back? It’s a really hard problem, actually. In the air in the room in front of us that we’re breathing, only two of the million molecules in front of us are methane. 417 or so are CO2. If you think direct air capture of CO2 is hard, direct air capture of methane is that much harder.

      The other thing that makes methane a challenge to abate is that activating the bonds in methane to promote its destruction or its removal is really, really tricky. It’s one of the smallest carbon-based molecules. It doesn’t have what we call “Van der Waals interactions”—there are no handles to grab onto. It’s not polar. That first destruction and that first C-H bond is what we as chemists would call “spin forbidden”. It’s hard to do and it takes a lot of energy to do that. One of the things we’ve developed in my lab is a catalyst that’s based on earth-abundant materials. There are some other groups at MIT that also work on these same types of materials. It’s able to convert methane at very low levels, down to the levels that we’re breathing in this room right now.

      Sally: That’s fascinating. do you see that as being something that will move to practical application?

      Desirée: One of the things that we’re doing to try to translate this to meaningful applications for the world is to scale the technology. We’re fortunate to have funding from several different sources, some private philanthropy groups and the United States Department of Energy. They’re helping us over the next three years try to scale this in places where it might matter most. Perhaps counterintuitive places, coal mines. Coal mines emit a lot of methane and it happens to be enriched in such a way that it releases energy. It might release enough energy to actually pay for the technology itself. Another place we’re really focused on is dairy.

      Sally: Really interesting. You mentioned at the beginning that you were at MIT, you left, you came back. I’m just wondering — I’m new to MIT and, obviously, I’m just learning it — but how do you think about the MIT community or culture in a way that is particularly helpful in advancing your work?

      Desirée: For me, I was really excited to come back to MIT because it is such an innovative place. If you’re someone who says, “I want to change the way we invent materials and processes,” it’s one of the best places you could possibly be. Because you can walk down the hall and bump into people who are making new things, new molecules, new materials, and say, “How can we incorporate the environment into our decision-making process?”

      As engineering professors, we’re guilty of teaching our students to optimize for performance and cost. They go out into their jobs, and guess what? That’s what they optimize for. We want to transition, and we’re at a point in our understanding of the earth system, that we could actually start to incorporate environmental objectives into that design process.

      Engineering professors of tomorrow should, say, optimize for performance and cost and the environment. That’s really what made me very excited to come back to MIT. Not just the great research that’s going on in every nook and corner of the Institute, but also thinking about how we might influence engineering education so that this becomes part of the fabric of how humans invent new practices and processes.

      Sally: If you look back in your past, you talked about your childhood in Maine and observing these patterns. You talked about your training and how you came to MIT and have really been, I think, thriving here. Was there a path not taken, a road not taken if you hadn’t become an environmental chemist? Was there something else you really wanted to do?

      Desirée: That’s such a great question. I have a lot of loves. I love the ocean. I love writing. I love teaching and I’m doing that, so I’m lucky there. I also love the beer business. My family’s in the beer business in Maine. I thought, as a biochemist, I would always be able to fall back on that if I needed to. My family’s not in the beer business because we’re particularly good at making beer, but because they’re interested in making businesses and creating opportunities for people. That’s been an important part of our role in the state of Maine.

      MIT really supports that side of my mind, as well. I love the entrepreneurial ecosystem that exists here. I love that when you bump into people and you have a crazy idea, instead of giving you all the reasons it won’t work, an MIT person gives you all the reasons it won’t work and then they say, “This is how we’re going to make it happen.” That’s really fun and exciting. The entrepreneurship environment that exists here is really very supportive of the translation process that has to happen to get something from the lab to the global impact that we’re looking for. That supports my mission just so much. It’s been a joy.

      Sally: That’s excellent. You weren’t actually tempted to become a yeast cell biologist in the service of beer production?

      Desirée: No, no, but I joke, “They only call me when something goes really bad.”

      Sally: That’s really funny. You experienced MIT as a student, now you’re experiencing it as a faculty member. What do you wish there was one thing about each group that the other knew?

      Desirée: I wish that, speaking with my faculty hat on, that the students knew just how much we care about them. I know that some of them do and really appreciate that. When I send an email at 3:00 in the morning, I get emails back from my colleagues at 3:00 in the morning. We work around the clock and we don’t do that for ourselves. We do that to make great sustainable systems for them and to create opportunity for them to propel themselves forward. To me, that’s one of the common unifying features of an MIT faculty member. We care really deeply about the student experience.

      As a student, I think that we’re hungry to learn. We wanted to really see the ins and outs of operation, how to run a research lab. I think sometimes faculty try to spare their students from that and maybe it’s okay to let them know just what’s going on in all those meetings that we sit through.

      Sally: That’s interesting. I think there are definitely things you find out when you become a faculty member and you’re like, “Oh, so this is what they were thinking.” With regard to the passion of the faculty about teaching, it really is remarkable here. I really think some of the strongest researchers here are so invested in teaching and you see that throughout the community.

      Desirée: It’s a labor of love for sure.

      Sally: Exactly. You talked a little bit about the passion for teaching. Were there teachers along your way that you really think impacted you and changed the direction of what you’re doing?

      Desirée: Yes, absolutely. I could name all of them. I had a kindergarten teacher who would stay after school and wait for my mom to be done work. I was raised by a single mom and her siblings and that was amazing. I had a fourth-grade teacher who helped promote me through school and taught me to love the environment. If you ask fourth graders if they saw any trash on the way to school, they’ll all say, “No.” You take them outside and give them a trash bag to fill up and it’ll be full by the end of the hour. This is something I’ve done with students in Cambridge to this day and this was many years on now. She really got me aware and thinking about environmental problems and how we might change systems.

      Sally: I think it’s really great for faculty to think about their own experiences, but also to hear people who become faculty members reflect on the great impact their own teachers had. I think the things folks are doing here are going to reverberate in their student’s minds for many, many years. It also is interesting in terms of thinking about the pipeline and when you get students interested in science. You talk about your own early years of education that really ultimately had an impact.

      It’s funny, when I became president at MIT, I got a note from my second-grade teacher. I remembered her like it was yesterday. These are people that really had an impact. It’s great that we honor teaching here at MIT and we acknowledge that this is going to have a really big impact on our student’s lives.

      Desirée: Yes, absolutely. It’s a privilege to teach these top talents. At many schools around the country, it’s just young people that have so much potential. I feel like when we walk into that classroom, we’ve got to bring inspiration with us along with the tangible, practical skills. It’s been great to see what they become.

      Sally: Tell me a little bit about what you do outside of work. When you ask faculty hobbies, sometimes I go, “Hobbies?” There must be something you spend your time on. I’m just curious.

      Desirée: We’re worried we’re going to fail this part of the Q&A. Yes. I have four children.

      Sally: You don’t need any hobbies then.

      Desirée: I know. It’s been the good graces of the academic institution. Just for those people who are out there thinking about going into academia and say, “It’s too hard. I couldn’t possibly have the work and life that I seek if I go into academia,” I don’t think that’s true anymore. I know there are a lot of women who paved the way for me, and men for that matter. I remember my PhD advisors being fully present for their children. I’ve been very fortunate to be able to do the same thing. I spend lots of time taking care of them right now. But we love being out in nature hiking, skiing, and kayaking and enjoying what the Earth gives us.

      Sally: It’s also fun to see that “aha” moment in your children when they start to learn a little bit about science and they get the idea that you really can discover things by observing closely. I don’t know if they realize they benefit from having parents who think that way, but I think that also stays with them through their lives.

      Desirée: My son is just waiting for the phone call to be able to be part of MIT’s toy design class.

      Sally: That’s fantastic.

      Desirée: As an official evaluator. Yes.

      Sally: In the last five years or so, we’ve been through the pandemic. In practical terms, how you think about your work and your life, what do you do that has improved your life? I always hate the words of “work-life balance” because they’re so intermeshed, but just for the broader community, how have you thought about that?

      Desirée: I’ve been thinking about my Zoom world and how I am still able to do quite a bit of talking to my colleagues and advancing the research mission and talking to my students that I wouldn’t have been able to do. Even pre-pandemic, it would’ve been pretty hard. We’re all really trained to interact more efficiently through these media and mechanisms. I know how to give a good talk on Zoom, for better or worse. I think that that’s been something that has been great.

      In the context of environment, I think a lot of us—this might be cliched at this point—but realize that there are things that we don’t need to get up on a plane for and perhaps we can work on the computer and interact in that way. I think that’s awesome. There’s not much that can replace real, in-person human interaction, but if it means that you can juggle a few more balls in the air and have your family feel valued and yourself feel valued while you’re also valuing your work that thing that is igniting for you, I think that’s a great outcome.

      Sally: I think that’s right. Unfortunately, though, your kids may never know the meaning of a snow day.

      Desirée: You got it.

      Sally: They may be on a remote school whenever we would’ve been home building snow forts.

      Desirée: As a Mainer, I appreciate this fully, and almost had to write a note this year. Just let them go outside.

      Sally: Exactly, exactly. As we’re wrapping up, just thinking about the future of climate work and coming back to the science, I think you’ve thought a lot about what you’re doing and impact on the climate. I’m just wondering, as you look around MIT, where you think we might have some of the greatest impact? How do you think about what some of your colleagues are doing? Because I’m starting to think a lot about what MIT’s real footprint in this area is going to be.

      Desirée: The first thing I want to say is that I think for a long time, the world’s been looking for a silver bullet climate solution. That is not how we got into this problem and it’s not how we’re going to get out of it.

      Sally: Exactly.

      Desirée: We need a thousand BBs. Fortunately, at MIT, there are many thousands of minds that all have something to contribute. I like to impose, especially on the undergraduates and the graduate researchers, our student population out there, think, “How can I bring my talents to bear on this really most pressing and important problem that’s facing our world right now?” I would say just whatever your skill is and whatever your passion is, try to find a way to marry those things together and find a way to have impact.

      The other thing I would say is that we think really differently about problems. That’s what might be needed. If you’re going to break systems, you need to come at it from a different perspective or a different angle. Encouraging people to think differently, as this community does so well, I think is going to be an enormous asset in bringing some solutions to the climate change challenge.

      Sally: Excellent. If you look back over your career, and even earlier than when you became a faculty member, what do you think the best advice is that you’ve ever been given?

      Desirée: There’s so much. I’ve been fortunate to have a lot of really great mentors. What is the best piece of advice? I think this notion of balancing work and not work. I’ve gotten two really key points of advice. One is about travel. I think that ties into this concept of COVID and whether now we can actually go remote for a lot of things. It was from an MIT professor. He said, “You know, the biggest thing you can do to protect your personal life and your life with your family is to say no and travel less. Travel eats up time on the front, in the back, and it’s your family that’s paying the price for that, so be really judicious about your choices.” That was excellent advice for me.

      Another female faculty member of mine said, “You have to prioritize your family like they are an appointment on your calendar and it’s okay when you do that.” I think those have been really helpful for me as I navigate and struggle with my own very mission-oriented self where I want to keep working and put my focus there, but know that it’s okay to maybe go for a walk and talk to real people.

      Sally: Go wild.

      Desirée: Yes, that’s right.

      Sally: This issue, actually, of saying no, not only to travel but thinking about where you really place your efforts and when there’s a finite amount of time. When I think about this—and advising junior faculty in terms of service—every faculty member is going to be asked way more things than they’re going to want to do. Yet, their service to the department, service to the Institute, is important, not only for their advancement but in how we create a community. I always advise people to say yes to the things they’re truly interested in and they’re passionate about, and there will be enough of those things.

      Desirée: I have a flowchart for when to say yes and when to say no. Having an interest is at the top of the list and then feeling like you’re going to have an impact. That’s something I think, when we do this service at MIT, we really are able to have an impact. It’s not just the oldest people in the room that get to drive the bus. They’re really listening and want to hear that perspective from everybody.

      Sally: That’s excellent. Thanks again, Desirée. I really enjoyed that conversation. To our audience, thanks again for listening to Curiosity Unbounded. I very much hope you’ll all join us again. I’m Sally Kornbluth. Stay curious. More

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      in Environment

      Even as temperatures rise, this hydrogel material keeps absorbing moisture

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      The vast majority of absorbent materials will lose their ability to retain water as temperatures rise. This is why our skin starts to sweat and why plants dry out in the heat. Even materials that are designed to soak up moisture, such as the silica gel packs in consumer packaging, will lose their sponge-like properties as their environment heats up.

      But one material appears to uniquely resist heat’s drying effects. MIT engineers have now found that polyethylene glycol (PEG) — a hydrogel commonly used in cosmetic creams, industrial coatings, and pharmaceutical capsules — can absorb moisture from the atmosphere even as temperatures climb.

      The material doubles its water absorption as temperatures climb from 25 to 50 degrees Celsius (77 to 122 degrees Fahrenheit), the team reports.

      PEG’s resilience stems from a heat-triggering transformation. As its surroundings heat up, the hydrogel’s microstructure morphs from a crystal to a less organized “amorphous” phase, which enhances the material’s ability to capture water.

      Based on PEG’s unique properties, the team developed a model that can be used to engineer other heat-resistant, water-absorbing materials. The group envisions such materials could one day be made into devices that harvest moisture from the air for drinking water, particularly in arid desert regions. The materials could also be incorporated into heat pumps and air conditioners to more efficiently regulate temperature and humidity.

      “A huge amount of energy consumption in buildings is used for thermal regulation,” says Lenan Zhang, a research scientist in MIT’s Department of Mechanical Engineering. “This material could be a key component of passive climate-control systems.”

      Zhang and his colleagues detail their work in a study appearing today in Advanced Materials. MIT co-authors include Xinyue Liu, Bachir El Fil, Carlos Diaz-Marin, Yang Zhong, Xiangyu Li, and Evelyn Wang, along with Shaoting Lin of Michigan State University.

      Against intuition

      Evelyn Wang’s group in MIT’s Device Research Lab aims to address energy and water challenges through the design of new materials and devices that sustainably manage water and heat. The team discovered PEG’s unusual properties as they were assessing a slew of similar hydrogels for their water-harvesting abilities.

      “We were looking for a high-performance material that could capture water for different applications,” Zhang says. “Hydrogels are a perfect candidate, because they are mostly made of water and a polymer network. They can simultaneously expand as they absorb water, making them ideal for regulating humidity and water vapor.”

      The team analyzed a variety of hydrogels, including PEG, by placing each material on a scale that was set within a climate-controlled chamber. A material became heavier as it absorbed more moisture. By recording a material’s changing weight, the researchers could track its ability to absorb moisture as they tuned the chamber’s temperature and humidity.

      What they observed was typical of most materials: as the temperature increased, the hyrogels’ ability to capture moisture from the air decreased. The reason for this temperature-dependence is well-understood: With heat comes motion, and at higher temperatures, water molecules move faster and are therefore more difficult to contain in most materials.

      “Our intuition tells us that at higher temperatures, materials tend to lose their ability to capture water,” says co-author Xinyue Liu. “So, we were very surprised by PEG because it has this inverse relationship.”

      In fact, they found that PEG grew heavier and continued to absorb water as the researchers raised the chamber’s temperature from 25 to 50 degrees Celsius.

      “At first, we thought we had measured some errors, and thought this could not be possible,” Liu says. “After we double-checked everything was correct in the experiment, we realized this was really happening, and this is the only known material that shows increasing water absorbing ability with higher temperature.”

      A lucky catch

      The group zeroed in on PEG to try and identify the reason for its unusual, heat-resilient performance. They found that the material has a natural melting point at around 50 degrees Celsius, meaning that the hydrogel’s normally crystal-like microstructure completely breaks down and transforms into an amorphous phase. Zhang says that this melted, amorphous phase provides more opportunity for polymers in the material to grab hold of any fast-moving water molecules.

      “In the crystal phase, there might be only a few sites on a polymer available to attract water and bind,” Zhang says. “But in the amorphous phase, you might have many more sites available. So, the overall performance can increase with increased temperature.”

      The team then developed a theory to predict how hydrogels absorb water, and showed that the theory could also explain PEG’s unusual behavior if the researchers added a “missing term” to the theory. That missing term was the effect of phase transformation. They found that when they included this effect, the theory could predict PEG’s behavior, along with that of other temperature-limiting hydrogels.

      The discovery of PEG’s unique properties was in large part by chance. The material’s melting temperature just happens to be within the range where water is a liquid, enabling them to catch PEG’s phase transformation and its resulting super-soaking behavior. The other hydrogels happen to have melting temperatures that fall outside this range. But the researchers suspect that these materials are also capable of similar phase transformations once they hit their melting temperatures.

      “Other polymers could in theory exhibit this same behavior, if we can engineer their melting points within a selected temperature range,” says team member Shaoting Lin.

      Now that the group has worked out a theory, they plan to use it as a blueprint to design materials specifically for capturing water at higher temperatures.

      “We want to customize our design to make sure a material can absorb a relatively high amount of water, at low humidity and high temperatures,” Liu says. “Then it could be used for atmospheric water harvesting, to bring people potable water in hot, arid environments.”

      This research was supported, in part, by U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy. More

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      in Energy

      MIT Energy Conference grapples with geopolitics

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      As Russia’s war in Ukraine rages on, this year’s MIT Energy Conference spotlighted the role of geopolitics in the world’s efforts to lower greenhouse gas emissions and mitigate the worst effects of climate change.

      Each year, the student-run conference, which its organizers say is the largest of its kind, brings together leaders from around the globe to discuss humanity’s most pressing energy and sustainability challenges.

      The event always involves perspectives from the investment, business, research, and startup communities. But this year, as more than 600 attendees gathered on April 11 and 12 for a whirlwind of keynote talks, fireside chats, and panel discussions, common themes also included the influence of Russia’s war, rising tensions between the U.S. and China, and international collaboration.

      As participants grappled with the evolving geopolitical landscape, some speakers encouraged moving past isolationist tendencies.

      “Some people push for self-sufficiency, others emphasize that we should not rely on trading partners that don’t share our values — I think both arguments are misguided,” said Juan Carlos Jobet, Chile’s former ministry of energy and mining. “No country has all that’s needed to create an energy system that’s affordable, clean, and secure. … A third of the world’s energy output is generated in nondemocratic countries. Can we really make our energy systems affordable and secure and curb climate change while excluding those countries from our collective effort? If we enter an area of protectionism and disintegration, we will all be worse off.”

      Another theme was optimism, such as that expressed by Volodymyr Kudrytskyi, CEO of Ukraine’s national power company, who spoke to the conference live from Kyiv. Kudrytskyi outlined Russia’s attacks on Ukraine’s power grids, which included more than 1,000 heavy missiles, making it the largest-ever campaign against a country’s power grid.

      Still, Kudrytskyi said he was confident he’d be able to attend the conference in person next year. As it happened, Kudrytskyi’s presentation marked the day Ukraine resumed its energy exports to other countries.

      “The good news is, after all of that, our system survived and continues operations,” he said.

      Energy security and the green transition

      Richard Duke, the U.S. Department of State’s deputy special envoy for climate, opened the conference with a keynote centered on the U.S.’ role in the global shift toward cleaner energy. Duke was among those advocating for a more integrated and diversified global energy system, noting that no country can address climate change on its own.

      “We need to do all of these things in parallel, in concert with other governments, and through the architecture of the Paris Climate agreement that wraps it together in ambitious net greenhouse gas abatement targets,” Duke said.

      Following his talk, Ditte Juul Jørgensen, the European Commission’s director general for energy, discussed the shift in the EU’s energy policies spurred by the Russian invasion of Ukraine.

      She admitted the EU had grown too dependent on Russian natural gas, but said the invasion forced European states to revise their energy strategy while keeping their long-term objective of net neutrality by 2050.

      “We see energy security and the green transition as interlinked. There is no energy security without the energy transition toward climate neutrality, and there’s no energy transition without energy security,” Jorgensen said.

      Jørgensen also outlined steps the EU has taken to improve its energy security over the last year, including rolling out additional renewable energy projects and replacing Russian fuel with fuel from the U.S., which has now become the continent’s main supplier of energy.

      “The fight against climate change is our shared ambition, it’s our shared responsibility, and I think we’ve shown over these last few years that we can turn that ambition into action and bring results,” she said.

      A challenge and an opportunity

      Optimism also shone through in the way speakers framed the green energy transition as a business opportunity. In keeping with the idea, the conference included a showcase of more than 30 startups focused on clean energy and sustainability.

      “We’re all battling a huge problem that needs a collective effort,” said Malav Sukhadia of Sol Clarity, a conference exhibitor that uses electricity to clean solar panels as a way to replace water cleaning. “This is one of the best energy conferences in the world. We felt if you’re in climate tech, you have to be here.”

      Technological development was a pillar of the conference, and a big topic in those discussions was green hydrogen, a clean fuel source that could replace natural gas in a number of applications and be produced using renewable energy. In one panel discussion on the technology, Sunita Satyapal of the Department of Energy noted the agency has been funding hydrogen development since the 1970s. Other panel members also stressed the maturity of the technology.

      “A lot of the technology needed to advance the ecosystem exists now,” said Laura Parkan, vice president of hydrogen energy at Air Liquide Americas. “The challenge is to get things to a large enough scale so that the costs come down to make it more affordable and really advance the hydrogen ecosystem.”

      Still, panel members acknowledged more technological development is needed to leverage the full potential of hydrogen, such as better mechanisms for storage and transportation.

      Other advanced technologies mentioned in panel discussions included advanced geothermal energy and small modular nuclear reactors that could be built and deployed more quickly than conventional reactors.

      “Exploring these different technologies may actually get us to the net zero — or even a zero carbon future — that we’re hoping for in electricity generation,” said Emma Wong of the OECD Nuclear Energy Agency, noting there are more than 80 advanced reactor designs that have been explored around the world. “There are various challenges and enabling conditions to be addressed, but places like China and Russia are already building these things, so there’s not a technological barrier.”

      “Glass half full”

      Despite the tall tasks that lie ahead, some speakers took a moment to celebrate accomplishments thus far.

      “It’s incredible to think about the progress we’ve made in the last 10 years,” said Neil Brown of the KKR investment firm, whose company is working to build a large offshore wind project. “Solar and wind and electric vehicles have gone from impossibly expensive and hard to imagine penetrating the market to being very close to, if not already at, cost parity. We’ve really come an awful long way.”

      Other speakers mixed their positivity with a confession of envy for the opportunity ahead of the young people in the audience, many of them students from MIT.

      “I have a mix of excitement from the speakers we’ve heard so far and a little bit of envy as well for the open road the young students and professionals here have in front of them,” said Jobert. “Coming back to this place has made me reconnect with the sense of opportunity and responsibility that I felt as a student.”

      Jobert offered lessons learned from his country’s struggles with an energy crisis, populist policies, and severe droughts. His talk finished with questions that struck at the heart of the conference.

      “The evidence is clear: The Earth will change. How much is still to be decided,” Jobert said. “The energy sector has been a central part of the problem. We now must work to become an essential pierce of the solution. Where should we focus our efforts? What can we learn from each other?” More

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      in Environment

      MIT PhD students honored for their work to solve critical issues in water and food

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      In 2017, the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) initiated the J-WAFS Fellowship Program for outstanding MIT PhD students working to solve humankind’s water-related challenges. Since then, J-WAFS has awarded 18 fellowships to students who have gone on to create innovations like a pump that can maximize energy efficiency even with changing flow rates, and a low-cost water filter made out of sapwood xylem that has seen real-world use in rural India. Last year, J-WAFS expanded eligibility to students with food-related research. The 2022 fellows included students working on micronutrient deficiency and plastic waste from traditional food packaging materials. 

      Today, J-WAFS has announced the award of the 2023-24 fellowships to Gokul Sampath and Jie Yun. A doctoral student in the Department of Urban Studies and planning, Sampath has been awarded the Rasikbhai L. Meswani Fellowship for Water Solutions, which is supported through a generous gift from Elina and Nikhil Meswani and family. Yun, who is in the Department of Civil and Environmental Engineering, received a J-WAFS Fellowship for Water and Food Solutions, which is funded by the J-WAFS Research Affiliate Program. Currently, Xylem, Inc. and GoAigua are J-WAFS’ Research Affiliate companies. A review committee comprised of MIT faculty and staff selected Sampath and Yun from a competitive field of outstanding graduate students working in water and food who were nominated by their faculty advisors. Sampath and Yun will receive one academic semester of funding, along with opportunities for networking and mentoring to advance their research.

      “Both Yun and Sampath have demonstrated excellence in their research,” says J-WAFS executive director Renee J. Robins. “They also stood out in their communication skills and their passion to work on issues of agricultural sustainability and resilience and access to safe water. We are so pleased to have them join our inspiring group of J-WAFS fellows,” she adds.

      Using behavioral health strategies to address the arsenic crisis in India and Bangladesh

      Gokul Sampath’s research centers on ways to improve access to safe drinking water in developing countries. A PhD candidate in the International Development Group in the Department of Urban Studies and Planning, his current work examines the issue of arsenic in drinking water sources in India and Bangladesh. In Eastern India, millions of shallow tube wells provide rural households a personal water source that is convenient, free, and mostly safe from cholera. Unfortunately, it is now known that one-in-four of these wells is contaminated with naturally occurring arsenic at levels dangerous to human health. As a result, approximately 40 million people across the region are at elevated risk of cancer, stroke, and heart disease from arsenic consumed through drinking water and cooked food. 

      Since the discovery of arsenic in wells in the late 1980s, governments and nongovernmental organizations have sought to address the problem in rural villages by providing safe community water sources. Yet despite access to safe alternatives, many households still consume water from their contaminated home wells. Sampath’s research seeks to understand the constraints and trade-offs that account for why many villagers don’t collect water from arsenic-safe government wells in the village, even when they know their own wells at home could be contaminated.

      Before coming to MIT, Sampath received a master’s degree in Middle East, South Asian, and African studies from Columbia University, as well as a bachelor’s degree in microbiology and history from the University of California at Davis. He has long worked on water management in India, beginning in 2015 as a Fulbright scholar studying households’ water source choices in arsenic-affected areas of the state of West Bengal. He also served as a senior research associate with the Abdul Latif Jameel Poverty Action Lab, where he conducted randomized evaluations of market incentives for groundwater conservation in Gujarat, India. Sampath’s advisor, Bishwapriya Sanyal, the Ford International Professor of Urban Development and Planning at MIT, says Sampath has shown “remarkable hard work and dedication.” In addition to his classes and research, Sampath taught the department’s undergraduate Introduction to International Development course, for which he received standout evaluations from students.

      This summer, Sampath will travel to India to conduct field work in four arsenic-affected villages in West Bengal to understand how social influence shapes villagers’ choices between arsenic-safe and unsafe water sources. Through longitudinal surveys, he hopes to connect data on the social ties between families in villages and the daily water source choices they make. Exclusionary practices in Indian village communities, especially the segregation of water sources on the basis of caste and religion, has long been suspected to be a barrier to equitable drinking water access in Indian villages. Yet despite this, planners seeking to expand safe water access in diverse Indian villages have rarely considered the way social divisions within communities might be working against their efforts. Sampath hopes to test whether the injunctive norms enabled by caste ties constrain villagers’ ability to choose the safest water source among those shared within the village. When he returns to MIT in the fall, he plans to dive into analyzing his survey data and start work on a publication.

      Understanding plant responses to stress to improve crop drought resistance and yield

      Plants, including crops, play a fundamental role in Earth’s ecosystems through their effects on climate, air quality, and water availability. At the same time, plants grown for agriculture put a burden on the environment as they require energy, irrigation, and chemical inputs. Understanding plant/environment interactions is becoming more and more important as intensifying drought is straining agricultural systems. Jie Yun, a PhD student in the Department of Civil and Environmental Engineering, is studying plant response to drought stress in the hopes of improving agricultural sustainability and yield under climate change.  Yun’s research focuses on genotype-by-environment interaction (GxE.) This relates to the observation that plant varieties respond to environmental changes differently. The effects of GxE in crop breeding can be exploited because differing environmental responses among varieties enables breeders to select for plants that demonstrate high stress-tolerant genotypes under particular growing conditions. Yun bases her studies on Brachypodium, a model grass species related to wheat, oat, barley, rye, and perennial forage grasses. By experimenting with this species, findings can be directly applied to cereal and forage crop improvement. For the first part of her thesis, Yun collaborated with Professor Caroline Uhler’s group in the Department of Electrical Engineering and Computer Science and the Institute for Data, Systems, and Society. Uhler’s computational tools helped Yun to evaluate gene regulatory networks and how they relate to plant resilience and environmental adaptation. This work will help identify the types of genes and pathways that drive differences in drought stress response among plant varieties.  David Des Marais, the Cecil and Ida Green Career Development Professor in the Department of Civil and Environmental Engineering, is Yun’s advisor. He notes, “throughout Jie’s time [at MIT] I have been struck by her intellectual curiosity, verging on fearlessness.” When she’s not mentoring undergraduate students in Des Marais’ lab, Yun is working on the second part of her project: how carbon allocation in plants and growth is affected by soil drying. One result of this work will be to understand which populations of plants harbor the necessary genetic diversity to adapt or acclimate to climate change. Another likely impact is identifying targets for the genetic improvement of crop species to increase crop yields with less water supply. Growing up in China, Yun witnessed environmental issues springing from the development of the steel industry, which caused contamination of rivers in her hometown. On one visit to her aunt’s house in rural China, she learned that water pollution was widespread after noticing wastewater was piped outside of the house into nearby farmland without being treated. These experiences led Yun to study water supply and sewage engineering for her undergraduate degree at Shenyang Jianzhu University. She then went on to complete a master’s program in civil and environmental engineering at Carnegie Mellon University. It was there that Yun discovered a passion for plant-environment interactions; during an independent study on perfluorooctanoic sulfonate, she realized the amazing ability of plants to adapt to environmental changes, toxins, and stresses. Her goal is to continue researching plant and environment interactions and to translate the latest scientific findings into applications that can improve food security. More

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      in Energy

      MIT engineers devise technology to prevent fouling in photobioreactors for CO2 capture

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      Algae grown in transparent tanks or tubes supplied with carbon dioxide can convert the greenhouse gas into other compounds, such as food supplements or fuels. But the process leads to a buildup of algae on the surfaces that clouds them and reduces efficiency, requiring laborious cleanout procedures every couple of weeks.

      MIT researchers have come up with a simple and inexpensive technology that could substantially limit this fouling, potentially allowing for a much more efficient and economical way of converting the unwanted greenhouse gas into useful products.

      The key is to coat the transparent containers with a material that can hold an electrostatic charge, and then applying a very small voltage to that layer. The system has worked well in lab-scale tests, and with further development might be applied to commercial production within a few years.

      The findings are being reported in the journal Advanced Functional Materials, in a paper by recent MIT graduate Victor Leon PhD ’23, professor of mechanical engineering Kripa Varanasi, former postdoc Baptiste Blanc, and undergraduate student Sophia Sonnert.

      No matter how successful efforts to reduce or eliminate carbon emissions may be, there will still be excess greenhouse gases that will remain in the atmosphere for centuries to come, continuing to affect global climate, Varanasi points out. “There’s already a lot of carbon dioxide there, so we have to look at negative emissions technologies as well,” he says, referring to ways of removing the greenhouse gas from the air or oceans, or from their sources before they get released into the air in the first place.

      When people think of biological approaches to carbon dioxide reduction, the first thought is usually of planting or protecting trees, which are indeed a crucial “sink” for atmospheric carbon. But there are others. “Marine algae account for about 50 percent of global carbon dioxide absorbed today on Earth,” Varanasi says. These algae grow anywhere from 10 to 50 times more quickly than land-based plants, and they can be grown in ponds or tanks that take up only a tenth of the land footprint of terrestrial plants.

      What’s more, the algae themselves can then be a useful product. “These algae are rich in proteins, vitamins and other nutrients,” Varanasi says, noting they could produce far more nutritional output per unit of land used than some traditional agricultural crops.

      If attached to the flue gas output of a coal or gas power plant, algae could not only thrive on the carbon dioxide as a nutrient source, but some of the microalgae species could also consume the associated nitrogen and sulfur oxides present in these emissions. “For every two or three kilograms of CO2, a kilogram of algae could be produced, and these could be used as biofuels, or for Omega-3, or food,” Varanasi says.

      Omega-3 fatty acids are a widely used food supplement, as they are an essential part of cell membranes and other tissues but cannot be made by the body and must be obtained from food. “Omega 3 is particularly attractive because it’s also a much higher-value product,” Varanasi says.

      Most algae grown commercially are cultivated in shallow ponds, while others are grown in transparent tubes called photobioreactors. The tubes can produce seven to 10 times greater yields than ponds for a given amount of land, but they face a major problem: The algae tend to build up on the transparent surfaces, requiring frequent shutdowns of the whole production system for cleaning, which can take as long as the productive part of the cycle, thus cutting overall output in half and adding to operational costs.

      The fouling also limits the design of the system. The tubes can’t be too small because the fouling would begin to block the flow of water through the bioreactor and require higher pumping rates.

      Varanasi and his team decided to try to use a natural characteristic of the algae cells to defend against fouling. Because the cells naturally carry a small negative electric charge on their membrane surface, the team figured that electrostatic repulsion could be used to push them away.

      The idea was to create a negative charge on the vessel walls, such that the electric field forces the algae cells away from the walls. To create such an electric field requires a high-performance dielectric material, which is an electrical insulator with a high “permittivity” that can produce a large change in surface charge with a smaller voltage.

      “What people have done before with applying voltage [to bioreactors] has been with conductive surfaces,” Leon explains, “but what we’re doing here is specifically with nonconductive surfaces.”

      He adds: “If it’s conductive, then you pass current and you’re kind of shocking the cells. What we’re trying to do is pure electrostatic repulsion, so the surface would be negative and the cell is negative so you get repulsion. Another way to describe it is like a force field, whereas before the cells were touching the surface and getting shocked.”

      The team worked with two different dielectric materials, silicon dioxide — essentially glass — and hafnia (hafnium oxide), both of which turned out to be far more efficient at minimizing fouling than conventional plastics used to make photobioreactors. The material can be applied in a coating that is vanishingly thin, just 10 to 20 nanometers (billionths of a meter) thick, so very little would be needed to coat a full photobioreactor system.

      “What we are excited about here is that we are able to show that purely from electrostatic interactions, we are able to control cell adhesion,” Varanasi says. “It’s almost like an on-off switch, to be able to do this.”

      Additionally, Leon says, “Since we’re using this electrostatic force, we don’t really expect it to be cell-specific, and we think there’s potential for applying it with other cells than just algae. In future work, we’d like to try using it with mammalian cells, bacteria, yeast, and so on.” It could also be used with other valuable types of algae, such as spirulina, that are widely used as food supplements.

      The same system could be used to either repel or attract cells by just reversing the voltage, depending on the particular application. Instead of algae, a similar setup might be used with human cells to produce artificial organs by producing a scaffold that could be charged to attract the cells into the right configuration, Varanasi suggests.

      “Our study basically solves this major problem of biofouling, which has been a bottleneck for photobioreactors,” he says. “With this technology, we can now really achieve the full potential” of such systems, although further development will be needed to scale up to practical, commercial systems.

      As for how soon this could be ready for widespread deployment, he says, “I don’t see why not in three years’ timeframe, if we get the right resources to be able to take this work forward.”

      The study was supported by energy company Eni S.p.A., through the MIT Energy Initiative. More