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      in Environment

      After more than a decade of successes, ESI’s work will spread out across the Institute

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      MIT’s Environmental Solutions Initiative (ESI), a pioneering cross-disciplinary body that helped give a major boost to sustainability and solutions to climate change at MIT, will close as a separate entity at the end of June. But that’s far from the end for its wide-ranging work, which will go forward under different auspices. Many of its key functions will become part of MIT’s recently launched Climate Project. John Fernandez, head of ESI for nearly a decade, will return to the School of Architecture and Planning, where some of ESI’s important work will continue as part of a new interdisciplinary lab.When the ideas that led to the founding of MIT’s Environmental Solutions Initiative first began to be discussed, its founders recall, there was already a great deal of work happening at MIT relating to climate change and sustainability. As Professor John Sterman of the MIT Sloan School of Management puts it, “there was a lot going on, but it wasn’t integrated. So the whole added up to less than the sum of its parts.”ESI was founded in 2014 to help fill that coordinating role, and in the years since it has accomplished a wide range of significant milestones in research, education, and communication about sustainable solutions in a wide range of areas. Its founding director, Professor Susan Solomon, helmed it for its first year, and then handed the leadership to Fernandez, who has led it since 2015.“There wasn’t much of an ecosystem [on sustainability] back then,” Solomon recalls. But with the help of ESI and some other entities, that ecosystem has blossomed. She says that Fernandez “has nurtured some incredible things under ESI,” including work on nature-based climate solutions, and also other areas such as sustainable mining, and reduction of plastics in the environment.Desiree Plata, director of MIT’s Climate and Sustainability Consortium and associate professor of civil and environmental engineering, says that one key achievement of the initiative has been in “communication with the external world, to help take really complex systems and topics and put them in not just plain-speak, but something that’s scientifically rigorous and defensible, for the outside world to consume.”In particular, ESI has created three very successful products, which continue under the auspices of the Climate Project. These include the popular TIL Climate Podcast, the Webby Award-winning Climate Portal website, and the online climate primer developed with Professor Kerry Emanuel. “These are some of the most frequented websites at MIT,” Plata says, and “the impact of this work on the global knowledge base cannot be overstated.”Fernandez says that ESI has played a significant part in helping to catalyze what has become “a rich institutional landscape of work in sustainability and climate change” at MIT. He emphasizes three major areas where he feels the ESI has been able to have the most impact: engaging the MIT community, initiating and stewarding critical environmental research, and catalyzing efforts to promote sustainability as fundamental to the mission of a research university.Engagement of the MIT community, he says, began with two programs: a research seed grant program and the creation of MIT’s undergraduate minor in environment and sustainability, launched in 2017.ESI also created a Rapid Response Group, which gave students a chance to work on real-world projects with external partners, including government agencies, community groups, nongovernmental organizations, and businesses. In the process, they often learned why dealing with environmental challenges in the real world takes so much longer than they might have thought, he says, and that a challenge that “seemed fairly straightforward at the outset turned out to be more complex and nuanced than expected.”The second major area, initiating and stewarding environmental research, grew into a set of six specific program areas: natural climate solutions, mining, cities and climate change, plastics and the environment, arts and climate, and climate justice.These efforts included collaborations with a Nobel Peace Prize laureate, three successive presidential administrations from Colombia, and members of communities affected by climate change, including coal miners, indigenous groups, various cities, companies, the U.N., many agencies — and the popular musical group Coldplay, which has pledged to work toward climate neutrality for its performances. “It was the role that the ESI played as a host and steward of these research programs that may serve as a key element of our legacy,” Fernandez says.The third broad area, he says, “is the idea that the ESI as an entity at MIT would catalyze this movement of a research university toward sustainability as a core priority.” While MIT was founded to be an academic partner to the industrialization of the world, “aren’t we in a different world now? The kind of massive infrastructure planning and investment and construction that needs to happen to decarbonize the energy system is maybe the largest industrialization effort ever undertaken. Even more than in the recent past, the set of priorities driving this have to do with sustainable development.”Overall, Fernandez says, “we did everything we could to infuse the Institute in its teaching and research activities with the idea that the world is now in dire need of sustainable solutions.”Fernandez “has nurtured some incredible things under ESI,” Solomon says. “It’s been a very strong and useful program, both for education and research.” But it is appropriate at this time to distribute its projects to other venues, she says. “We do now have a major thrust in the Climate Project, and you don’t want to have redundancies and overlaps between the two.”Fernandez says “one of the missions of the Climate Project is really acting to coalesce and aggregate lots of work around MIT.” Now, with the Climate Project itself, along with the Climate Policy Center and the Center for Sustainability Science and Strategy, it makes more sense for ESI’s climate-related projects to be integrated into these new entities, and other projects that are less directly connected to climate to take their places in various appropriate departments or labs, he says.“We did enough with ESI that we made it possible for these other centers to really flourish,” he says. “And in that sense, we played our role.”As of June 1, Fernandez has returned to his role as professor of architecture and urbanism and building technology in the School of Architecture and Planning, where he directs the Urban Metabolism Group. He will also be starting up a new group called Environment ResearchAction (ERA) to continue ESI work in cities, nature, and artificial intelligence.  More

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      in Energy

      Decarbonizing steel is as tough as steel

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      The long-term aspirational goal of the Paris Agreement on climate change is to cap global warming at 1.5 degrees Celsius above preindustrial levels, and thereby reduce the frequency and severity of floods, droughts, wildfires, and other extreme weather events. Achieving that goal will require a massive reduction in global carbon dioxide (CO2) emissions across all economic sectors. A major roadblock, however, could be the industrial sector, which accounts for roughly 25 percent of global energy- and process-related CO2 emissions — particularly within the iron and steel sector, industry’s largest emitter of CO2.Iron and steel production now relies heavily on fossil fuels (coal or natural gas) for heat, converting iron ore to iron, and making steel strong. Steelmaking could be decarbonized by a combination of several methods, including carbon capture technology, the use of low- or zero-carbon fuels, and increased use of recycled steel. Now a new study in the Journal of Cleaner Production systematically explores the viability of different iron-and-steel decarbonization strategies.Today’s strategy menu includes improving energy efficiency, switching fuels and technologies, using more scrap steel, and reducing demand. Using the MIT Economic Projection and Policy Analysis model, a multi-sector, multi-region model of the world economy, researchers at MIT, the University of Illinois at Urbana-Champaign, and ExxonMobil Technology and Engineering Co. evaluate the decarbonization potential of replacing coal-based production processes with electric arc furnaces (EAF), along with either scrap steel or “direct reduced iron” (DRI), which is fueled by natural gas with carbon capture and storage (NG CCS DRI-EAF) or by hydrogen (H2 DRI-EAF).Under a global climate mitigation scenario aligned with the 1.5 C climate goal, these advanced steelmaking technologies could result in deep decarbonization of the iron and steel sector by 2050, as long as technology costs are low enough to enable large-scale deployment. Higher costs would favor the replacement of coal with electricity and natural gas, greater use of scrap steel, and reduced demand, resulting in a more-than-50-percent reduction in emissions relative to current levels. Lower technology costs would enable massive deployment of NG CCS DRI-EAF or H2 DRI-EAF, reducing emissions by up to 75 percent.Even without adoption of these advanced technologies, the iron-and-steel sector could significantly reduce its CO2 emissions intensity (how much CO2 is released per unit of production) with existing steelmaking technologies, primarily by replacing coal with gas and electricity (especially if it is generated by renewable energy sources), using more scrap steel, and implementing energy efficiency measures.“The iron and steel industry needs to combine several strategies to substantially reduce its emissions by mid-century, including an increase in recycling, but investing in cost reductions in hydrogen pathways and carbon capture and sequestration will enable even deeper emissions mitigation in the sector,” says study supervising author Sergey Paltsev, deputy director of the MIT Center for Sustainability Science and Strategy (MIT CS3) and a senior research scientist at the MIT Energy Initiative (MITEI).This study was supported by MIT CS3 and ExxonMobil through its membership in MITEI. More

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      in Energy

      “Each of us holds a piece of the solution”

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      MIT has an unparalleled history of bringing together interdisciplinary teams to solve pressing problems — think of the development of radar during World War II, or leading the international coalition that cracked the code of the human genome — but the challenge of climate change could demand a scale of collaboration unlike any that’s come before at MIT.“Solving climate change is not just about new technologies or better models. It’s about forging new partnerships across campus and beyond — between scientists and economists, between architects and data scientists, between policymakers and physicists, between anthropologists and engineers, and more,” MIT Vice President for Energy and Climate Evelyn Wang told an energetic crowd of faculty, students, and staff on May 6. “Each of us holds a piece of the solution — but only together can we see the whole.”Undeterred by heavy rain, approximately 300 campus community members filled the atrium in the Tina and Hamid Moghadam Building (Building 55) for a spring gathering hosted by Wang and the Climate Project at MIT. The initiative seeks to direct the full strength of MIT to address climate change, which Wang described as one of the defining challenges of this moment in history — and one of its greatest opportunities.“It calls on us to rethink how we power our world, how we build, how we live — and how we work together,” Wang said. “And there is no better place than MIT to lead this kind of bold, integrated effort. Our culture of curiosity, rigor, and relentless experimentation makes us uniquely suited to cross boundaries — to break down silos and build something new.”The Climate Project is organized around six missions, thematic areas in which MIT aims to make significant impact, ranging from decarbonizing industry to new policy approaches to designing resilient cities. The faculty leaders of these missions posed challenges to the crowd before circulating among the crowd to share their perspectives and to discuss community questions and ideas.Wang and the Climate Project team were joined by a number of research groups, startups, and MIT offices conducting relevant work today on issues related to energy and climate. For example, the MIT Office of Sustainability showcased efforts to use the MIT campus as a living laboratory; MIT spinouts such as Forma Systems, which is developing high-performance, low-carbon building systems, and Addis Energy, which envisions using the earth as a reactor to produce clean ammonia, presented their technologies; and visitors learned about current projects in MIT labs, including DebunkBot, an artificial intelligence-powered chatbot that can persuade people to shift their attitudes about conspiracies, developed by David Rand, the Erwin H. Schell Professor at the MIT Sloan School of Management.Benedetto Marelli, an associate professor in the Department of Civil and Environmental Engineering who leads the Wild Cards Mission, said the energy and enthusiasm that filled the room was inspiring — but that the individual conversations were equally valuable.“I was especially pleased to see so many students come out. I also spoke with other faculty, talked to staff from across the Institute, and met representatives of external companies interested in collaborating with MIT,” Marelli said. “You could see connections being made all around the room, which is exactly what we need as we build momentum for the Climate Project.” More

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      in Security

      Guardian Ag’s crop-spraying drone is replacing dangerous pilot missions

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      Every year during the growing season, thousands of pilots across the country climb into small planes loaded with hundreds of pounds of pesticides and fly extremely close to the ground at upward of 140 miles an hour, unloading their cargo onto rows of corn, cotton, and soybeans.The world of agricultural aviation is as dangerous as it is vital to America’s farms. Unfortunately, fatal crashes are common. Now Guardian Ag, founded by former MIT Electronics Research Society (MITERS) makers Adam Bercu and Charles Guan ’11, is offering an alternative in the form of a large, purpose-built drone that can autonomously deliver 200-pound payloads across farms. The company’s drones feature an 18-foot spray radius, 80-inch rotors, a custom battery pack, and aerospace-grade materials designed to make crop spraying more safe, efficient, and inexpensive for farmers.“We’re trying to bring technology to American farms that are hundreds or thousands of acres, where you’re not replacing a human with a hand pump — you’re replacing a John Deere tractor or a helicopter or an airplane,” Bercu says.“With Guardian, the operator shows up about 30 minutes before they want to spray, they mix the product, path plan the field in our app, and it gives an estimate for how long the job will take,” he says. “With our fast charging, you recharge the aircraft while you fill the tank, and those two operations take about the same amount of time.”

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      From Battlebots to farmlandsAt a young age, Bercu became obsessed with building robots. Growing up in south Florida, he’d attend robotic competitions, build prototypes, and even dumpster dive for particularly hard-to-find components. At one competition, Bercu met Charles Guan, who would go on to major in mechanical engineering at MIT, and the two robot enthusiasts became lifelong friends.“When Charles came to MIT, he basically convinced me to move to Cambridge,” Bercu says. “He said, ‘You need to come up here. I found more people like us. Hackers!’”Bercu visited Cambridge, Massachusetts, and indeed fell in love with the region’s makerspaces and hacker culture. He moved soon after, and he and Guan began spending free time at spaces including the Artisans Asylum makerspace in Somerville, Massachusetts; MIT’s International Design Center; and the MIT Electronics Research Society (MITERS) makerspace. Guan held several leadership positions at MITERS, including facilities manager, treasurer, and president.“MIT offered enormous latitude to its students to be independent and creative, which was reflected in the degree of autonomy they permit student-run organizations like MITERS to have compared to other top-tier schools,” Guan says. “It was a key selling point to me when I was touring mechanical engineering labs as a junior in high school. I was well-known in the department circle for being at MITERS all the time, possibly even more than I spent on classes.”After Guan graduated, he and Bercu started a hardware consulting business and competed in the robot combat show Battlebots. Guan also began working as a design instructor in MIT’s Department of Mechanical Engineering, where he taught a section of Course 2.007 that tasked students with building go-karts.Eventually, Guan and Bercu decided to use their experience to start a drone company.“Over the course of Battlebots and building go-karts, we knew electric batteries were getting really cheap and electric vehicle supply chains were established,” Bercu explains. “People were raising money to build eVTOL [electric vertical take-off and landing] vehicles to transport people, but we knew diesel fuel still outperformed batteries over long distances. Where electric systems did outperform combustion engines was in areas where you needed peak power for short periods of time. Basically, batteries are awesome when you have a short mission.”That idea made the founders think crop spraying could be a good early application. Bercu’s family runs an aviation business, and he knew pilots who would spray crops as their second jobs.“It’s one of those high-paying but very dangerous jobs,” Bercu says. “Even in the U.S., we lose between 1 and 2 percent of all agriculture pilots each year to fatal accidents. These people are rolling the dice every time they do this: You’re flying 6 feet off the ground at 140 miles an hour with 800 gallons of pesticide in your tank.”After cobbling together spare parts from Battlebots and their consulting business, the founders built a 600-pound drone. When they finally got it to fly, they decided the time was right to launch their company, receiving crucial early guidance and their first funding from the MIT-affiliated investment firm the E14 Fund.The founders spent the next year interviewing crop dusters and farmers. They also started engaging with the Federal Aviation Administration.“There was no category for anything like this,” Bercu explains. “With the FAA, we not only got through the approval process, we helped them build the process as we went through it, because we wanted to establish some common-sense standards.”Guardian custom-built its batteries to optimize throughput and utilization rate of its drones. Depending on the farm, Bercu says his machines can unload about 1.5 to 2 tons of payload per hour.Guardian’s drones can also spray more precisely than planes, reducing the environmental impact of pesticides, which often pollute the landscapes and waterways surrounding farms.“This thing has the precision to spray the ‘Mona Lisa’ on 20 acres, but we’re not leveraging that functionality today,” Bercu says. “For the operator we want to make it very easy. The goal is to take someone who sprays with a tractor and teach them to spray with a drone in less than a week.”Scaling for farmersTo date, Guardian Ag has built eight of its aircraft, which are actively delivering payloads over California farms in trials with paying customers. The company is currently ramping up manufacturing in its 60,000-square-foot facility in Massachusetts, and Bercu says Guardian has a backlog of hundreds of millions of dollars-worth of drones.“Grower demand has been exceptional,” Bercu says. “We don’t need to educate them on the need for this. They see the big drone with the big tank and they’re in.”Bercu envisions Guardian’s drones helping with a number of other tasks like ship-to-ship logistics, delivering supplies to offshore oil rigs, mining, and other areas where helicopters and small aircraft are currently flown through difficult terrain. But for now, the company is focused on starting with agriculture.“Agriculture is such an important and foundational aspect of our country,” says Guardian Ag chief operating officer Ashley Ferguson MBA ’19. “We work with multigenerational farming families, and when we talk to them, it’s clear aerial spray has taken hold in the industry. But there’s a large shortage of pilots, especially for agriculture applications. So, it’s clear there’s a big opportunity.”Seven years since founding Guardian, Bercu remains grateful that MIT’s community opened its doors for him when he moved to Cambridge.“Without the MIT community, this company wouldn’t be possible,” Bercu says. “I was never able to go to college, but I’d love to one day apply to MIT and do my engineering undergrad or go to the Sloan School of Management. I’ll never forget MIT’s openness to me. It’s a place I hold near and dear to my heart.” More

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      in Environment

      Day of Climate inspires young learners to take action

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      “Close your eyes and imagine we are on the same team. Same arena. Same jersey. And the game is on the line,” Jaylen Brown, the 2024 NBA Finals MVP for the Boston Celtics, said to a packed room of about 200 people at the recent Day of Climate event at the MIT Museum.“Now think about this: We aren’t playing for ourselves; we are playing for the next generation,” Brown added, encouraging attendees to take climate action. The inaugural Day of Climate event brought together local learners, educators, community leaders, and the MIT community. Featuring project showcases, panels, and a speaker series, the event sparked hands-on learning and inspired climate action across all ages.The event marked the celebration of the first year of a larger initiative by the same name. Led by the pK-12 team at MIT Open Learning, Day of Climate has brought together learners and educators by offering free, hands-on curriculum lessons and activities designed to introduce learners to climate change, teach how it shapes their lives, and consider its effects on humanity. Cynthia Breazeal, dean of digital learning at MIT Open Learning, notes the breadth of engagement across MIT that made the event, and the larger initiative, possible with contributions from more than 10 different MIT departments, labs, centers, and initiatives. “MIT is passionate about K-12 education,” she says. “It was truly inspiring to witness how our entire community came together to demonstrate the power of collaboration and advocacy in driving meaningful change.”From education to action The event kicked off with a showcase, where the Day of Climate grantees and learners invited attendees to learn about their projects and meaningfully engage with lessons and activities. Aranya Karighattam, a local high school senior, adapted the curriculum Urban Heat Islands — developed by Lelia Hampton, a PhD student in electrical engineering and computer science at MIT, and Chris Rabe, program director at the MIT Environmental Solution Initiative — sharing how this phenomenon affects the Boston metropolitan area. 

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      Day of Climate inspires young learners to take actionVideo: MIT Open Learning

      Karighattam discussed what could be done to shield local communities from urban heat islands. They suggested doubling the tree cover in areas with the lowest quartile tree coverage as one mitigating strategy, but noted that even small steps, like building a garden and raising awareness for this issue, can help.Day of Climate echoed a consistent call to action, urging attendees to meaningfully engage in both education and action. Brown, who is an MIT Media Lab Director’s Fellow, spoke about how education and collective action will pave the way to tackle big societal challenges. “We need to invest in sustainability communities,” he said. “We need to invest in clean technology, and we need to invest in education that fosters environmental stewardship.”Part of MIT’s broader sustainability efforts, including The Climate Project, the event reflected a commitment to building a resilient and sustainable future for all. Influenced by the Climate Action Through Education (CATE), Day of Climate panelist Sophie Shen shared how climate education inspired her civic life. “Learning about climate change has inspired me to take action on a wider systemic level,” she said.Shen, a senior at Arlington High School and local elected official, emphasized how engagement and action looks different for everyone. “There are so many ways to get involved,” she said. “That could be starting a community garden — those can be great community hubs and learning spaces — or it could include advocating to your local or state governments.”Becoming a catalyst for change The larger Day of Climate initiative encourages young people to understand the interdisciplinary nature of climate change and consider how the changing climate impacts many aspects of life. With curriculum available for learners from ages 4 to 18, these free activities range from Climate Change Charades — where learners act out words like “deforestation” and “recycling” — to Climate Change Happens Below Water, where learners use sensors to analyze water quality data like pH and solubility.Many of the speakers at the event shared personal anecdotes from their childhood about how climate education, both in and out of the classroom, has changed the trajectory of their lives. Addaline Jorroff, deputy climate chief and director of mitigation and community resilience in the Office of Climate Resilience and Innovation for the Commonwealth of Massachusetts, explained how resources from MIT were instrumental in her education as a middle and high schooler, while Jaylen Brown told how his grandmother helped him see the importance of taking care of the planet, through recycling and picking up trash together, when he was young.Claudia Urrea, director of the pK-12 team at Open Learning and director of Day of Climate, emphasizes how providing opportunities at schools — through new curriculum, classroom resources and mentorship — are crucial, but providing other educational opportunities also matter: in particular, opportunities that support learners in becoming strong leaders.“I strongly believe that this event not only inspired young learners to take meaningful action, both large and small, towards a better future, but also motivated all the stakeholders to continue to create opportunities for these young learners to emerge as future leaders,” Urrea says.The team plans to hold the Day of Climate event annually, bringing together young people, educators, and the MIT community. Urrea hopes the event will act as a catalyst for change — for everyone.“We hope Day of Climate serves as the opportunity for everyone to recognize the interconnectedness of our actions,” Urrea says. “Understanding this larger system is crucial for addressing current and future challenges, ultimately making the world a better place for all.”The Day of Climate event was hosted by the Day of Climate team in collaboration with MIT Climate Action Through Education (CATE) and Earth Day Boston. More

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      in Environment

      Study helps pinpoint areas where microplastics will accumulate

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      The accumulation of microplastics in the environment, and within our bodies, is an increasingly worrisome issue. But predicting where these ubiquitous particles will accumulate, and therefore where remediation efforts should be focused, has been difficult because of the many factors that contribute to their dispersal and deposition.New research from MIT shows that one key factor in determining where microparticles are likely to build up has to do with the presence of biofilms. These thin, sticky biopolymer layers are shed by microorganisms and can accumulate on surfaces, including along sandy riverbeds or seashores. The study found that, all other conditions being equal, microparticles are less likely to accumulate in sediment infused with biofilms, because if they land there, they are more likely to be resuspended by flowing water and carried away.The open-access findings appear in the journal Geophysical Research Letters, in a paper by MIT postdoc Hyoungchul Park and professor of civil and environmental engineering Heidi Nepf. “Microplastics are definitely in the news a lot,” Nepf says, “and we don’t fully understand where the hotspots of accumulation are likely to be. This work gives a little bit of guidance” on some of the factors that can cause these particles, and small particles in general, to accumulate in certain locations.Most experiments looking at the ways microparticles are transported and deposited have been conducted over bare sand, Park says. “But in nature, there are a lot of microorganisms, such as bacteria, fungi, and algae, and when they adhere to the stream bed they generate some sticky things.” These substances are known as extracellular polymeric substances, or EPS, and they “can significantly affect the channel bed characteristics,” he says. The new research focused on determining exactly how these substances affected the transport of microparticles, including microplastics.The research involved a flow tank with a bottom lined with fine sand, and sometimes with vertical plastic tubes simulating the presence of mangrove roots. In some experiments the bed consisted of pure sand, and in others the sand was mixed with a biological material to simulate the natural biofilms found in many riverbed and seashore environments.Water mixed with tiny plastic particles was pumped through the tank for three hours, and then the bed surface was photographed under ultraviolet light that caused the plastic particles to fluoresce, allowing a quantitative measurement of their concentration.The results revealed two different phenomena that affected how much of the plastic accumulated on the different surfaces. Immediately around the rods that stood in for above-ground roots, turbulence prevented particle deposition. In addition, as the amount of simulated biofilms in the sediment bed increased, the accumulation of particles also decreased.Nepf and Park concluded that the biofilms filled up the spaces between the sand grains, leaving less room for the microparticles to fit in. The particles were more exposed because they penetrated less deeply in between the sand grains, and as a result they were much more easily resuspended and carried away by the flowing water.“These biological films fill the pore spaces between the sediment grains,” Park explains, “and that makes the deposited particles — the particles that land on the bed — more exposed to the forces generated by the flow, which makes it easier for them to be resuspended. What we found was that in a channel with the same flow conditions and the same vegetation and the same sand bed, if one is without EPS and one is with EPS, then the one without EPS has a much higher deposition rate than the one with EPS.”Nepf adds: “The biofilm is blocking the plastics from accumulating in the bed because they can’t go deep into the bed. They just stay right on the surface, and then they get picked up and moved elsewhere. So, if I spilled a large amount of microplastic in two rivers, and one had a sandy or gravel bottom, and one was muddier with more biofilm, I would expect more of the microplastics to be retained in the sandy or gravelly river.”All of this is complicated by other factors, such as the turbulence of the water or the roughness of the bottom surface, she says. But it provides a “nice lens” to provide some suggestions for people who are trying to study the impacts of microplastics in the field. “They’re trying to determine what kinds of habitats these plastics are in, and this gives a framework for how you might categorize those habitats,” she says. “It gives guidance to where you should go to find more plastics versus less.”As an example, Park suggests, in mangrove ecosystems, microplastics may preferentially accumulate in the outer edges, which tend to be sandy, while the interior zones have sediment with more biofilm. Thus, this work suggests “the sandy outer regions may be potential hotspots for microplastic accumulation,” he says, and can make this a priority zone for monitoring and protection.“This is a highly relevant finding,” says Isabella Schalko, a research scientist at ETH Zurich, who was not associated with this research. “It suggests that restoration measures such as re-vegetation or promoting biofilm growth could help mitigate microplastic accumulation in aquatic systems. It highlights the powerful role of biological and physical features in shaping particle transport processes.”The work was supported by Shell International Exploration and Production through the MIT Energy Initiative. More

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      in Energy

      Study shows making hydrogen with soda cans and seawater is scalable and sustainable

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      Hydrogen has the potential to be a climate-friendly fuel since it doesn’t release carbon dioxide when used as an energy source. Currently, however, most methods for producing hydrogen involve fossil fuels, making hydrogen less of a “green” fuel over its entire life cycle.A new process developed by MIT engineers could significantly shrink the carbon footprint associated with making hydrogen.Last year, the team reported that they could produce hydrogen gas by combining seawater, recycled soda cans, and caffeine. The question then was whether the benchtop process could be applied at an industrial scale, and at what environmental cost.Now, the researchers have carried out a “cradle-to-grave” life cycle assessment, taking into account every step in the process at an industrial scale. For instance, the team calculated the carbon emissions associated with acquiring and processing aluminum, reacting it with seawater to produce hydrogen, and transporting the fuel to gas stations, where drivers could tap into hydrogen tanks to power engines or fuel cell cars. They found that, from end to end, the new process could generate a fraction of the carbon emissions that is associated with conventional hydrogen production.In a study appearing today in Cell Reports Sustainability, the team reports that for every kilogram of hydrogen produced, the process would generate 1.45 kilograms of carbon dioxide over its entire life cycle. In comparison, fossil-fuel-based processes emit 11 kilograms of carbon dioxide per kilogram of hydrogen generated.The low-carbon footprint is on par with other proposed “green hydrogen” technologies, such as those powered by solar and wind energy.“We’re in the ballpark of green hydrogen,” says lead author Aly Kombargi PhD ’25, who graduated this spring from MIT with a doctorate in mechanical engineering. “This work highlights aluminum’s potential as a clean energy source and offers a scalable pathway for low-emission hydrogen deployment in transportation and remote energy systems.”The study’s MIT co-authors are Brooke Bao, Enoch Ellis, and professor of mechanical engineering Douglas Hart.Gas bubbleDropping an aluminum can in water won’t normally cause much of a chemical reaction. That’s because when aluminum is exposed to oxygen, it instantly forms a shield-like layer. Without this layer, aluminum exists in its pure form and can readily react when mixed with water. The reaction that occurs involves aluminum atoms that efficiently break up molecules of water, producing aluminum oxide and pure hydrogen. And it doesn’t take much of the metal to bubble up a significant amount of the gas.“One of the main benefits of using aluminum is the energy density per unit volume,” Kombargi says. “With a very small amount of aluminum fuel, you can conceivably supply much of the power for a hydrogen-fueled vehicle.”Last year, he and Hart developed a recipe for aluminum-based hydrogen production. They found they could puncture aluminum’s natural shield by treating it with a small amount of gallium-indium, which is a rare-metal alloy that effectively scrubs aluminum into its pure form. The researchers then mixed pellets of pure aluminum with seawater and observed that the reaction produced pure hydrogen. What’s more, the salt in the water helped to precipitate gallium-indium, which the team could subsequently recover and reuse to generate more hydrogen, in a cost-saving, sustainable cycle.“We were explaining the science of this process in conferences, and the questions we would get were, ‘How much does this cost?’ and, ‘What’s its carbon footprint?’” Kombargi says. “So we wanted to look at the process in a comprehensive way.”A sustainable cycleFor their new study, Kombargi and his colleagues carried out a life cycle assessment to estimate the environmental impact of aluminum-based hydrogen production, at every step of the process, from sourcing the aluminum to transporting the hydrogen after production. They set out to calculate the amount of carbon associated with generating 1 kilogram of hydrogen — an amount that they chose as a practical, consumer-level illustration.“With a hydrogen fuel cell car using 1 kilogram of hydrogen, you can go between 60 to 100 kilometers, depending on the efficiency of the fuel cell,” Kombargi notes.They performed the analysis using Earthster — an online life cycle assessment tool that draws data from a large repository of products and processes and their associated carbon emissions. The team considered a number of scenarios to produce hydrogen using aluminum, from starting with “primary” aluminum mined from the Earth, versus “secondary” aluminum that is recycled from soda cans and other products, and using various methods to transport the aluminum and hydrogen.After running life cycle assessments for about a dozen scenarios, the team identified one scenario with the lowest carbon footprint. This scenario centers on recycled aluminum — a source that saves a significant amount of emissions compared with mining aluminum — and seawater — a natural resource that also saves money by recovering gallium-indium. They found that this scenario, from start to finish, would generate about 1.45 kilograms of carbon dioxide for every kilogram of hydrogen produced. The cost of the fuel produced, they calculated, would be about $9 per kilogram, which is comparable to the price of hydrogen that would be generated with other green technologies such as wind and solar energy.The researchers envision that if the low-carbon process were ramped up to a commercial scale, it would look something like this: The production chain would start with scrap aluminum sourced from a recycling center. The aluminum would be shredded into pellets and treated with gallium-indium. Then, drivers could transport the pretreated pellets as aluminum “fuel,” rather than directly transporting hydrogen, which is potentially volatile. The pellets would be transported to a fuel station that ideally would be situated near a source of seawater, which could then be mixed with the aluminum, on demand, to produce hydrogen. A consumer could then directly pump the gas into a car with either an internal combustion engine or a fuel cell.The entire process does produce an aluminum-based byproduct, boehmite, which is a mineral that is commonly used in fabricating semiconductors, electronic elements, and a number of industrial products. Kombargi says that if this byproduct were recovered after hydrogen production, it could be sold to manufacturers, further bringing down the cost of the process as a whole.“There are a lot of things to consider,” Kombargi says. “But the process works, which is the most exciting part. And we show that it can be environmentally sustainable.”The group is continuing to develop the process. They recently designed a small reactor, about the size of a water bottle, that takes in aluminum pellets and seawater to generate hydrogen, enough to power an electric bike for several hours. They previously demonstrated that the process can produce enough hydrogen to fuel a small car. The team is also exploring underwater applications, and are designing a hydrogen reactor that would take in surrounding seawater to power a small boat or underwater vehicle.This research was supported, in part, by the MIT Portugal Program. More

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      AI stirs up the recipe for concrete in MIT study

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      For weeks, the whiteboard in the lab was crowded with scribbles, diagrams, and chemical formulas. A research team across the Olivetti Group and the MIT Concrete Sustainability Hub (CSHub) was working intensely on a key problem: How can we reduce the amount of cement in concrete to save on costs and emissions? The question was certainly not new; materials like fly ash, a byproduct of coal production, and slag, a byproduct of steelmaking, have long been used to replace some of the cement in concrete mixes. However, the demand for these products is outpacing supply as industry looks to reduce its climate impacts by expanding their use, making the search for alternatives urgent. The challenge that the team discovered wasn’t a lack of candidates; the problem was that there were too many to sort through.On May 17, the team, led by postdoc Soroush Mahjoubi, published an open-access paper in Nature’s Communications Materials outlining their solution. “We realized that AI was the key to moving forward,” notes Mahjoubi. “There is so much data out there on potential materials — hundreds of thousands of pages of scientific literature. Sorting through them would have taken many lifetimes of work, by which time more materials would have been discovered!”With large language models, like the chatbots many of us use daily, the team built a machine-learning framework that evaluates and sorts candidate materials based on their physical and chemical properties. “First, there is hydraulic reactivity. The reason that concrete is strong is that cement — the ‘glue’ that holds it together — hardens when exposed to water. So, if we replace this glue, we need to make sure the substitute reacts similarly,” explains Mahjoubi. “Second, there is pozzolanicity. This is when a material reacts with calcium hydroxide, a byproduct created when cement meets water, to make the concrete harder and stronger over time.  We need to balance the hydraulic and pozzolanic materials in the mix so the concrete performs at its best.”Analyzing scientific literature and over 1 million rock samples, the team used the framework to sort candidate materials into 19 types, ranging from biomass to mining byproducts to demolished construction materials. Mahjoubi and his team found that suitable materials were available globally — and, more impressively, many could be incorporated into concrete mixes just by grinding them. This means it’s possible to extract emissions and cost savings without much additional processing. “Some of the most interesting materials that could replace a portion of cement are ceramics,” notes Mahjoubi. “Old tiles, bricks, pottery — all these materials may have high reactivity. That’s something we’ve observed in ancient Roman concrete, where ceramics were added to help waterproof structures. I’ve had many interesting conversations on this with Professor Admir Masic, who leads a lot of the ancient concrete studies here at MIT.”The potential of everyday materials like ceramics and industrial materials like mine tailings is an example of how materials like concrete can help enable a circular economy. By identifying and repurposing materials that would otherwise end up in landfills, researchers and industry can help to give these materials a second life as part of our buildings and infrastructure.Looking ahead, the research team is planning to upgrade the framework to be capable of assessing even more materials, while experimentally validating some of the best candidates. “AI tools have gotten this research far in a short time, and we are excited to see how the latest developments in large language models enable the next steps,” says Professor Elsa Olivetti, senior author on the work and member of the MIT Department of Materials Science and Engineering. She serves as an MIT Climate Project mission director, a CSHub principal investigator, and the leader of the Olivetti Group.“Concrete is the backbone of the built environment,” says Randolph Kirchain, co-author and CSHub director. “By applying data science and AI tools to material design, we hope to support industry efforts to build more sustainably, without compromising on strength, safety, or durability.In addition to Mahjoubi, Olivetti, and Kirchain, co-authors on the work include MIT postdoc Vineeth Venugopal, Ipek Bensu Manav SM ’21, PhD ’24; and CSHub Deputy Director Hessam AzariJafari. More