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      in Environment

      Making steel with electricity

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      Steel is one of the most useful materials on the planet. A backbone of modern life, it’s used in skyscrapers, cars, airplanes, bridges, and more. Unfortunately, steelmaking is an extremely dirty process.The most common way it’s produced involves mining iron ore, reducing it in a blast furnace through the addition of coal, and then using an oxygen furnace to burn off excess carbon and other impurities. That’s why steel production accounts for around 7 to 9 percent of humanity’s greenhouse gas emissions worldwide, making it one of the dirtiest industries on the planet.Now Boston Metal is seeking to clean up the steelmaking industry using an electrochemical process called molten oxide electrolysis (MOE), which eliminates many steps in steelmaking and releases oxygen as its sole byproduct.The company, which was founded by MIT Professor Emeritus Donald Sadoway, Professor Antoine Allanore, and James Yurko PhD ’01, is already using MOE to recover high-value metals from mining waste at its Brazilian subsidiary, Boston Metal do Brasil. That work is helping Boston Metal’s team deploy its technology at commercial scale and establish key partnerships with mining operators. It has also built a prototype MOE reactor to produce green steel at its headquarters in Woburn, Massachusetts.And despite its name, Boston Metal has global ambitions. The company has raised more than $370 million to date from organizations across Europe, Asia, the Americas, and the Middle East, and its leaders expect to scale up rapidly to transform steel production in every corner of the world.“There’s a worldwide recognition that we need to act rapidly, and that’s going to happen through technology solutions like this that can help us move away from incumbent technologies,” Boston Metal Chief Scientist and former MIT postdoc Guillaume Lambotte says. “More and more, climate change is a part of our lives, so the pressure is on everyone to act fast.”To the moon and backThe origins of Boston Metal’s technology start on the moon. In the mid 2000s, Sadoway, who is the John F. Elliott Professor Emeritus of Materials Chemistry in MIT’s Department of Materials Science, received a grant from NASA to explore ways to produce oxygen for future lunar bases. Sadoway and other MIT researchers explored the idea of sending an electric current through the iron oxide rock on the moon’s surface, using rock from an old asteroid in Arizona for their experiments. The reaction produced oxygen, with metal as a byproduct.The research stuck with Sadoway, who noticed that down here on Earth, that metal byproduct would be of interest. To help make the electrolysis reaction he studied more viable, he joined forces with Allanore, who is a professor of metallurgy at MIT and the Lechtman Chair in the Department of Materials Science and Engineering. The professors were able to identify a less expensive anode and partnered with Yurko, a former student, to found Boston Metal.“All of the fundamental studies and the initial technologies came out of MIT,” Lambotte says. “We spun out of research that was patented at MIT and licensed from MIT’s Technology Licensing Office.”Lambotte joined the company shortly after Boston Metal’s team published a 2013 paper in Nature describing the MOE platform.“That’s when it went from the lab, with a coffee cup-sized experiment to prove the fundamentals and produce a few grams, to a company that can produce hundreds of kilograms, and soon, tons of metal,” Lambotte says.

      Boston Metal’s process takes place in modular MOE cells the size of a school bus. Here is a schematic of the process.

      Boston Metal’s molten oxide electrolysis process takes place in modular MOE cells the size of a school bus. Iron ore rock is fed into the cell, which contains the cathode (the negative terminal of the MOE cell) and an anode immersed in a liquid electrolyte. The anode is inert, meaning it doesn’t dissolve in the electrolyte or take part in the reaction other than serving as the positive terminal. When electricity runs between the anode and cathode and the cell reaches around 1,600 degrees Celsius, the iron oxide bonds in the ore are split, producing pure liquid metal at the bottom that can be tapped. The byproduct of the reaction is oxygen, and the process doesn’t require water, hazardous chemicals, or precious-metal catalysts.The production of each cell depends on the size of its current. Lambotte says with about 600,000 amps, each cell could produce up to 10 tons of metal every day. Steelmakers would license Boston Metal’s technology and deploy as many cells as needed to reach their production targets.Boston Metal is already using MOE to help mining companies recover high-value metals from their mining waste, which usually needs to undergo costly treatment or storage. Lambotte says it could also be used to produce many other kinds of metals down the line, and Boston Metal was recently selected to negotiate grant funding to produce chromium metal — critical for a number of clean energy applications — in West Virginia.“If you look around the world, a lot of the feedstocks for metal are oxides, and if it’s an oxide, then there’s a chance we can work with that feedstock,” Lambotte says. “There’s a lot of excitement because everyone needs a solution capable of decarbonizing the metal industry, so a lot of people are interested to understand where MOE fits in their own processes.”Gigatons of potentialBoston Metal’s steel decarbonization technology is currently slated to reach commercial-scale in 2026, though its Brazil plant is already introducing the industry to MOE.“I think it’s a window for the metal industry to get acquainted with MOE and see how it works,” Lambotte says. “You need people in the industry to grasp this technology. It’s where you form connections and how new technology spreads.”The Brazilian plant runs on 100 percent renewable energy.“We can be the beneficiary of this tremendous worldwide push to decarbonize the energy sector,” Lambotte says. “I think our approach goes hand in hand with that. Fully green steel requires green electricity, and I think what you’ll see is deployment of this technology where [clean electricity] is already readily available.”Boston Metal’s team is excited about MOE’s application across the metals industry but is focused first and foremost on eliminating the gigatons of emissions from steel production.“Steel produces around 10 percent of global emissions, so that is our north star,” Lambotte says. “Everyone is pledging carbon reductions, emissions reductions, and making net zero goals, so the steel industry is really looking hard for viable technology solutions. People are ready for new approaches.” More

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      in Energy

      H2 underground

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      In 1987 in a village in Mali, workers were digging a water well when they felt a rush of air. One of the workers was smoking a cigarette, and the air caught fire, burning a clear blue flame. The well was capped at the time, but in 2012, it was tapped to provide energy for the village, powering a generator for nine years.The fuel source: geologic hydrogen.For decades, hydrogen has been discussed as a potentially revolutionary fuel. But efforts to produce “green” hydrogen (splitting water into hydrogen and oxygen using renewable electricity), “grey” hydrogen (making hydrogen from methane and releasing the biproduct carbon dioxide (CO2) into the atmosphere), “brown” hydrogen (produced through the gasification of coal), and “blue” hydrogen (making hydrogen from methane but capturing the CO2) have thus far proven either expensive and/or energy-intensive. Enter geologic hydrogen. Also known as “orange,” “gold,” “white,” “natural,” and even “clear” hydrogen, geologic hydrogen is generated by natural geochemical processes in the Earth’s crust. While there is still much to learn, a growing number of researchers and industry leaders are hopeful that it may turn out to be an abundant and affordable resource lying right beneath our feet.“There’s a tremendous amount of uncertainty about this,” noted Robert Stoner, the founding director of the MIT Tata Center for Technology and Design, in his opening remarks at the MIT Energy Initiative (MITEI) Spring Symposium. “But the prospect of readily producible clean hydrogen showing up all over the world is a potential near-term game changer.”A new hope for hydrogenThis April, MITEI gathered researchers, industry leaders, and academic experts from around MIT and the world to discuss the challenges and opportunities posed by geologic hydrogen in a daylong symposium entitled “Geologic hydrogen: Are orange and gold the new green?” The field is so new that, until a year ago, the U.S. Department of Energy (DOE)’s website incorrectly claimed that hydrogen only occurs naturally on Earth in compound forms, chemically bonded to other elements.“There’s a common misconception that hydrogen doesn’t occur naturally on Earth,” said Geoffrey Ellis, a research geologist with the U.S. Geological Survey. He noted that natural hydrogen production tends to occur in different locations from where oil and natural gas are likely to be discovered, which explains why geologic hydrogen discoveries have been relatively rare, at least until recently.“Petroleum exploration is not targeting hydrogen,” Ellis said. “Companies are simply not really looking for it, they’re not interested in it, and oftentimes they don’t measure for it. The energy industry spends billions of dollars every year on exploration with very sophisticated technology, and still they drill dry holes all the time. So I think it’s naive to think that we would suddenly be finding hydrogen all the time when we’re not looking for it.”In fact, the number of researchers and startup energy companies with targeted efforts to characterize geologic hydrogen has increased over the past several years — and these searches have uncovered new prospects, said Mary Haas, a venture partner at Breakthrough Energy Ventures. “We’ve seen a dramatic uptick in exploratory activity, now that there is a focused effort by a small community worldwide. At Breakthrough Energy, we are excited about the potential of this space, as well as our role in accelerating its progress,” she said. Haas noted that if geologic hydrogen could be produced at $1 per kilogram, this would be consistent with the DOE’s targeted “liftoff” point for the energy source. “If that happens,” she said, “it would be transformative.”Haas noted that only a small portion of identified hydrogen sites are currently under commercial exploration, and she cautioned that it’s not yet clear how large a role the resource might play in the transition to green energy. But, she said, “It’s worthwhile and important to find out.”Inventing a new energy subsectorGeologic hydrogen is produced when water reacts with iron-rich minerals in rock. Researchers and industry are exploring how to stimulate this natural production by pumping water into promising deposits.In any new exploration area, teams must ask a series of questions to qualify the site, said Avon McIntyre, the executive director of HyTerra Ltd., an Australian company focused on the exploration and production of geologic hydrogen. These questions include: Is the geology favorable? Does local legislation allow for exploration and production? Does the site offer a clear path to value? And what are the carbon implications of producing hydrogen at the site?“We have to be humble,” McIntyre said. “We can’t be too prescriptive and think that we’ll leap straight into success. We have a unique opportunity to stop and think about what this industry will look like, how it will work, and how we can bring together various disciplines.” This was a theme that arose multiple times over the course of the symposium: the idea that many different stakeholders — including those from academia, industry, and government — will need to work together to explore the viability of geologic hydrogen and bring it to market at scale.In addition to the potential for hydrogen production to give rise to greenhouse gas emissions (in cases, for instance, where hydrogen deposits are contaminated with natural gas), researchers and industry must also consider landscape deformation and even potential seismic implications, said Bradford Hager, the Cecil and Ida Green Professor of Earth Sciences in the MIT Department of Earth, Atmospheric and Planetary Sciences.The surface impacts of hydrogen exploration and production will likely be similar to those caused by the hydro-fracturing process (“fracking”) used in oil and natural gas extraction, Hager said.“There will be unavoidable surface deformation. In most places, you don’t want this if there’s infrastructure around,” Hager said. “Seismicity in the stimulated zone itself should not be a problem, because the areas are tested first. But we need to avoid stressing surrounding brittle rocks.”McIntyre noted that the commercial case for hydrogen remains a challenge to quantify, without even a “spot” price that companies can use to make economic calculations. Early on, he said, capturing helium at hydrogen exploration sites could be a path to early cash flow, but that may ultimately serve as a “distraction” as teams attempt to scale up to the primary goal of hydrogen production. He also noted that it is not even yet clear whether hard rock, soft rock, or underwater environments hold the most potential for geologic hydrogen, but all show promise.“If you stack all of these things together,” McIntyre said, “what we end up doing may look very different from what we think we’re going to do right now.”The path aheadWhile the long-term prospects for geologic hydrogen are shrouded in uncertainty, most speakers at the symposium struck a tone of optimism. Ellis noted that the DOE has dedicated $20 million in funding to a stimulated hydrogen program. Paris Smalls, the co-founder and CEO of Eden GeoPower Inc., said “we think there is a path” to producing geologic hydrogen below the $1 per kilogram threshold. And Iwnetim Abate, an assistant professor in the MIT Department of Materials Science and Engineering, said that geologic hydrogen opens up the idea of Earth as a “factory to produce clean fuels,” utilizing the subsurface heat and pressure instead of relying on burning fossil fuels or natural gas for the same purpose.“Earth has had 4.6 billion years to do these experiments,” said Oliver Jagoutz, a professor of geology in the MIT Department of Earth, Atmospheric and Planetary Sciences. “So there is probably a very good solution out there.”Alexis Templeton, a professor of geological sciences at the University of Colorado at Boulder, made the case for moving quickly. “Let’s go to pilot, faster than you might think,” she said. “Why? Because we do have some systems that we understand. We could test the engineering approaches and make sure that we are doing the right tool development, the right technology development, the right experiments in the lab. To do that, we desperately need data from the field.”“This is growing so fast,” Templeton added. “The momentum and the development of geologic hydrogen is really quite substantial. We need to start getting data at scale. And then, I think, more people will jump off the sidelines very quickly.”  More

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      Researchers develop a detector for continuously monitoring toxic gases

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      Most systems used to detect toxic gases in industrial or domestic settings can be used only once, or at best a few times. Now, researchers at MIT have developed a detector that could provide continuous monitoring for the presence of these gases, at low cost.The new system combines two existing technologies, bringing them together in a way that preserves the advantages of each while avoiding their limitations. The team used a material called a metal-organic framework, or MOF, which is highly sensitive to tiny traces of gas but whose performance quickly degrades, and combined it with a polymer material that is highly durable and easier to process, but much less sensitive.The results are reported today in the journal Advanced Materials, in a paper by MIT professors Aristide Gumyusenge, Mircea Dinca, Heather Kulik, and Jesus del Alamo, graduate student Heejung Roh, and postdocs Dong-Ha Kim, Yeongsu Cho, and Young-Moo Jo.Highly porous and with large surface areas, MOFs come in a variety of compositions. Some can be insulators, but the ones used for this work are highly electrically conductive. With their sponge-like form, they are effective at capturing molecules of various gases, and the sizes of their pores can be tailored to make them selective for particular kinds of gases. “If you are using them as a sensor, you can recognize if the gas is there if it has an effect on the resistivity of the MOF,” says Gumyusenge, the paper’s senior author and the Merton C. Flemings Career Development Assistant Professor of Materials Science and Engineering.The drawback for these materials’ use as detectors for gases is that they readily become saturated, and then can no longer detect and quantify new inputs. “That’s not what you want. You want to be able to detect and reuse,” Gumyusenge says. “So, we decided to use a polymer composite to achieve this reversibility.”The team used a class of conductive polymers that Gumyusenge and his co-workers had previously shown can respond to gases without permanently binding to them. “The polymer, even though it doesn’t have the high surface area that the MOFs do, will at least provide this recognize-and-release type of phenomenon,” he says.The team combined the polymers in a liquid solution along with the MOF material in powdered form, and deposited the mixture on a substrate, where they dry into a uniform, thin coating. By combining the polymer, with its quick detection capability, and the more sensitive MOFs, in a one-to-one ratio, he says, “suddenly we get a sensor that has both the high sensitivity we get from the MOF and the reversibility that is enabled by the presence of the polymer.”The material changes its electrical resistance when molecules of the gas are temporarily trapped in the material. These changes in resistance can be continuously monitored by simply attaching an ohmmeter to track the resistance over time. Gumyusenge and his students demonstrated the composite material’s ability to detect nitrogen dioxide, a toxic gas produced by many kinds of combustion, in a small lab-scale device. After 100 cycles of detection, the material was still maintaining its baseline performance within a margin of about 5 to 10 percent, demonstrating its long-term use potential.In addition, this material has far greater sensitivity than most presently used detectors for nitrogen dioxide, the team reports. This gas is often detected after the use of stove ovens. And, with this gas recently linked to many asthma cases in the U.S., reliable detection in low concentrations is important. The team demonstrated that this new composite could detect, reversibly, the gas at concentrations as low as 2 parts per million.While their demonstration was specifically aimed at nitrogen dioxide, Gumyusenge says, “we can definitely tailor the chemistry to target other volatile molecules,” as long as they are small polar analytes, “which tend to be most of the toxic gases.”Besides being compatible with a simple hand-held detector or a smoke-alarm type of device, one advantage of the material is that the polymer allows it to be deposited as an extremely thin uniform film, unlike regular MOFs, which are generally in an inefficient powder form. Because the films are so thin, there is little material needed and production material costs could be low; the processing methods could be typical of those used for industrial coating processes. “So, maybe the limiting factor will be scaling up the synthesis of the polymers, which we’ve been synthesizing in small amounts,” Gumyusenge says.“The next steps will be to evaluate these in real-life settings,” he says. For example, the material could be applied as a coating on chimneys or exhaust pipes to continuously monitor gases through readings from an attached resistance monitoring device. In such settings, he says, “we need tests to check if we truly differentiate it from other potential contaminants that we might have overlooked in the lab setting. Let’s put the sensors out in real-world scenarios and see how they do.”The work was supported by the MIT Climate and Sustainability Consortium (MCSC), the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) at MIT, and the U.S. Department of Energy. More

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      Elaine Liu: Charging ahead

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      MIT senior Elaine Siyu Liu doesn’t own an electric car, or any car. But she sees the impact of electric vehicles (EVs) and renewables on the grid as two pieces of an energy puzzle she wants to solve.The U.S. Department of Energy reports that the number of public and private EV charging ports nearly doubled in the past three years, and many more are in the works. Users expect to plug in at their convenience, charge up, and drive away. But what if the grid can’t handle it?Electricity demand, long stagnant in the United States, has spiked due to EVs, data centers that drive artificial intelligence, and industry. Grid planners forecast an increase of 2.6 percent to 4.7 percent in electricity demand over the next five years, according to data reported to federal regulators. Everyone from EV charging-station operators to utility-system operators needs help navigating a system in flux.That’s where Liu’s work comes in.Liu, who is studying mathematics and electrical engineering and computer science (EECS), is interested in distribution — how to get electricity from a centralized location to consumers. “I see power systems as a good venue for theoretical research as an application tool,” she says. “I’m interested in it because I’m familiar with the optimization and probability techniques used to map this level of problem.”Liu grew up in Beijing, then after middle school moved with her parents to Canada and enrolled in a prep school in Oakville, Ontario, 30 miles outside Toronto.Liu stumbled upon an opportunity to take part in a regional math competition and eventually started a math club, but at the time, the school’s culture surrounding math surprised her. Being exposed to what seemed to be some students’ aversion to math, she says, “I don’t think my feelings about math changed. I think my feelings about how people feel about math changed.”Liu brought her passion for math to MIT. The summer after her sophomore year, she took on the first of the two Undergraduate Research Opportunity Program projects she completed with electric power system expert Marija Ilić, a joint adjunct professor in EECS and a senior research scientist at the MIT Laboratory for Information and Decision Systems.Predicting the gridSince 2022, with the help of funding from the MIT Energy Initiative (MITEI), Liu has been working with Ilić on identifying ways in which the grid is challenged.One factor is the addition of renewables to the energy pipeline. A gap in wind or sun might cause a lag in power generation. If this lag occurs during peak demand, it could mean trouble for a grid already taxed by extreme weather and other unforeseen events.If you think of the grid as a network of dozens of interconnected parts, once an element in the network fails — say, a tree downs a transmission line — the electricity that used to go through that line needs to be rerouted. This may overload other lines, creating what’s known as a cascade failure.“This all happens really quickly and has very large downstream effects,” Liu says. “Millions of people will have instant blackouts.”Even if the system can handle a single downed line, Liu notes that “the nuance is that there are now a lot of renewables, and renewables are less predictable. You can’t predict a gap in wind or sun. When such things happen, there’s suddenly not enough generation and too much demand. So the same kind of failure would happen, but on a larger and more uncontrollable scale.”Renewables’ varying output has the added complication of causing voltage fluctuations. “We plug in our devices expecting a voltage of 110, but because of oscillations, you will never get exactly 110,” Liu says. “So even when you can deliver enough electricity, if you can’t deliver it at the specific voltage level that is required, that’s a problem.”Liu and Ilić are building a model to predict how and when the grid might fail. Lacking access to privatized data, Liu runs her models with European industry data and test cases made available to universities. “I have a fake power grid that I run my experiments on,” she says. “You can take the same tool and run it on the real power grid.”Liu’s model predicts cascade failures as they evolve. Supply from a wind generator, for example, might drop precipitously over the course of an hour. The model analyzes which substations and which households will be affected. “After we know we need to do something, this prediction tool can enable system operators to strategically intervene ahead of time,” Liu says.Dictating price and powerLast year, Liu turned her attention to EVs, which provide a different kind of challenge than renewables.In 2022, S&P Global reported that lawmakers argued that the U.S. Federal Energy Regulatory Commission’s (FERC) wholesale power rate structure was unfair for EV charging station operators.In addition to operators paying by the kilowatt-hour, some also pay more for electricity during peak demand hours. Only a few EVs charging up during those hours could result in higher costs for the operator even if their overall energy use is low.Anticipating how much power EVs will need is more complex than predicting energy needed for, say, heating and cooling. Unlike buildings, EVs move around, making it difficult to predict energy consumption at any given time. “If users don’t like the price at one charging station or how long the line is, they’ll go somewhere else,” Liu says. “Where to allocate EV chargers is a problem that a lot of people are dealing with right now.”One approach would be for FERC to dictate to EV users when and where to charge and what price they’ll pay. To Liu, this isn’t an attractive option. “No one likes to be told what to do,” she says.Liu is looking at optimizing a market-based solution that would be acceptable to top-level energy producers — wind and solar farms and nuclear plants — all the way down to the municipal aggregators that secure electricity at competitive rates and oversee distribution to the consumer.Analyzing the location, movement, and behavior patterns of all the EVs driven daily in Boston and other major energy hubs, she notes, could help demand aggregators determine where to place EV chargers and how much to charge consumers, akin to Walmart deciding how much to mark up wholesale eggs in different markets.Last year, Liu presented the work at MITEI’s annual research conference. This spring, Liu and Ilić are submitting a paper on the market optimization analysis to a journal of the Institute of Electrical and Electronics Engineers.Liu has come to terms with her early introduction to attitudes toward STEM that struck her as markedly different from those in China. She says, “I think the (prep) school had a very strong ‘math is for nerds’ vibe, especially for girls. There was a ‘why are you giving yourself more work?’ kind of mentality. But over time, I just learned to disregard that.”After graduation, Liu, the only undergraduate researcher in Ilić’s MIT Electric Energy Systems Group, plans to apply to fellowships and graduate programs in EECS, applied math, and operations research.Based on her analysis, Liu says that the market could effectively determine the price and availability of charging stations. Offering incentives for EV owners to charge during the day instead of at night when demand is high could help avoid grid overload and prevent extra costs to operators. “People would still retain the ability to go to a different charging station if they chose to,” she says. “I’m arguing that this works.” More

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      Repurposed beer yeast may offer a cost-effective way to remove lead from water

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      Every year, beer breweries generate and discard thousands of tons of surplus yeast. Researchers from MIT and Georgia Tech have now come up with a way to repurpose that yeast to absorb lead from contaminated water.Through a process called biosorption, yeast can quickly absorb even trace amounts of lead and other heavy metals from water. The researchers showed that they could package the yeast inside hydrogel capsules to create a filter that removes lead from water. Because the yeast cells are encapsulated, they can be easily removed from the water once it’s ready to drink.“We have the hydrogel surrounding the free yeast that exists in the center, and this is porous enough to let water come in, interact with yeast as if they were freely moving in water, and then come out clean,” says Patricia Stathatou, a former postdoc at the MIT Center for Bits and Atoms, who is now a research scientist at Georgia Tech and an incoming assistant professor at Georgia Tech’s School of Chemical and Biomolecular Engineering. “The fact that the yeast themselves are bio-based, benign, and biodegradable is a significant advantage over traditional technologies.”The researchers envision that this process could be used to filter drinking water coming out of a faucet in homes, or scaled up to treat large quantities of water at treatment plants.MIT graduate student Devashish Gokhale and Stathatou are the lead authors of the study, which appears today in the journal RSC Sustainability. Patrick Doyle, the Robert T. Haslam Professor of Chemical Engineering at MIT, is the senior author of the paper, and Christos Athanasiou, an assistant professor of aerospace engineering at Georgia Tech and a former visiting scholar at MIT, is also an author.Absorbing leadThe new study builds on work that Stathatou and Athanasiou began in 2021, when Athanasiou was a visiting scholar at MIT’s Center for Bits and Atoms. That year, they calculated that waste yeast discarded from a single brewery in Boston would be enough to treat the city’s entire water supply.Through biosorption, a process that is not fully understood, yeast cells can bind to and absorb heavy metal ions, even at challenging initial concentrations below 1 part per million. The MIT team found that this process could effectively decontaminate water with low concentrations of lead. However, one key obstacle remained, which was how to remove yeast from the water after they absorb the lead.In a serendipitous coincidence, Stathatou and Athanasiou happened to present their research at the AIChE Annual Meeting in Boston in 2021, where Gokhale, a student in Doyle’s lab, was presenting his own research on using hydrogels to capture micropollutants in water. The two sets of researchers decided to join forces and explore whether the yeast-based strategy could be easier to scale up if the yeast were encapsulated in hydrogels developed by Gokhale and Doyle.“What we decided to do was make these hollow capsules — something like a multivitamin pill, but instead of filling them up with vitamins, we fill them up with yeast cells,” Gokhale says. “These capsules are porous, so the water can go into the capsules and the yeast are able to bind all of that lead, but the yeast themselves can’t escape into the water.”The capsules are made from a polymer called polyethylene glycol (PEG), which is widely used in medical applications. To form the capsules, the researchers suspend freeze-dried yeast in water, then mix them with the polymer subunits. When UV light is shone on the mixture, the polymers link together to form capsules with yeast trapped inside.Each capsule is about half a millimeter in diameter. Because the hydrogels are very thin and porous, water can easily pass through and encounter the yeast inside, while the yeast remain trapped.In this study, the researchers showed that the encapsulated yeast could remove trace lead from water just as rapidly as the unencapsulated yeast from Stathatou and Athanasiou’s original 2021 study.Scaling upLed by Athanasiou, the researchers tested the mechanical stability of the hydrogel capsules and found that the capsules and the yeast inside can withstand forces similar to those generated by water running from a faucet. They also calculated that the yeast-laden capsules should be able to withstand forces generated by flows in water treatment plants serving several hundred residences.“Lack of mechanical robustness is a common cause of failure of previous attempts to scale-up biosorption using immobilized cells; in our work we wanted to make sure that this aspect is thoroughly addressed from the very beginning to ensure scalability,” Athanasiou says.After assessing the mechanical robustness of the yeast-laden capsules, the researchers constructed a proof-of-concept packed-bed biofilter, capable of treating trace lead-contaminated water and meeting U.S. Environmental Protection Agency drinking water guidelines while operating continuously for 12 days.This process would likely consume less energy than existing physicochemical processes for removing trace inorganic compounds from water, such as precipitation and membrane filtration, the researchers say.This approach, rooted in circular economy principles, could minimize waste and environmental impact while also fostering economic opportunities within local communities. Although numerous lead contamination incidents have been reported in various locations in the United States, this approach could have an especially significant impact in low-income areas that have historically faced environmental pollution and limited access to clean water, and may not be able to afford other ways to remediate it, the researchers say.“We think that there’s an interesting environmental justice aspect to this, especially when you start with something as low-cost and sustainable as yeast, which is essentially available anywhere,” Gokhale says.The researchers are now exploring strategies for recycling and replacing the yeast once they’re used up, and trying to calculate how often that will need to occur. They also hope to investigate whether they could use feedstocks derived from biomass to make the hydrogels, instead of fossil-fuel-based polymers, and whether the yeast can be used to capture other types of contaminants.“Moving forward, this is a technology that can be evolved to target other trace contaminants of emerging concern, such as PFAS or even microplastics,” Stathatou says. “We really view this as an example with a lot of potential applications in the future.”The research was funded by the Rasikbhai L. Meswani Fellowship for Water Solutions, the MIT Abdul Latif Jameel Water and Food Systems Lab (J-WAFS), and the Renewable Bioproducts Institute at Georgia Tech. More

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      Scientists develop an affordable sensor for lead contamination

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      Engineers at MIT, Nanytang Technological University, and several companies have developed a compact and inexpensive technology for detecting and measuring lead concentrations in water, potentially enabling a significant advance in tackling this persistent global health issue.The World Health Organization estimates that 240 million people worldwide are exposed to drinking water that contains unsafe amounts of toxic lead, which can affect brain development in children, cause birth defects, and produce a variety of neurological, cardiac, and other damaging effects. In the United States alone, an estimated 10 million households still get drinking water delivered through lead pipes.“It’s an unaddressed public health crisis that leads to over 1 million deaths annually,” says Jia Xu Brian Sia, an MIT postdoc and the senior author of the paper describing the new technology.But testing for lead in water requires expensive, cumbersome equipment and typically requires days to get results. Or, it uses simple test strips that simply reveal a yes-or-no answer about the presence of lead but no information about its concentration. Current EPA regulations require drinking water to contain no more that 15 parts per billion of lead, a concentration so low it is difficult to detect.The new system, which could be ready for commercial deployment within two or three years, could detect lead concentrations as low as 1 part per billion, with high accuracy, using a simple chip-based detector housed in a handheld device. The technology gives nearly instant quantitative measurements and requires just a droplet of water.The findings are described in a paper appearing today in the journal Nature Communications, by Sia, MIT graduate student and lead author Luigi Ranno, Professor Juejun Hu, and 12 others at MIT and other institutions in academia and industry.The team set out to find a simple detection method based on the use of photonic chips, which use light to perform measurements. The challenging part was finding a way to attach to the photonic chip surface certain ring-shaped molecules known as crown ethers, which can capture specific ions such as lead. After years of effort, they were able to achieve that attachment via a chemical process known as Fischer esterification. “That is one of the essential breakthroughs we have made in this technology,” Sia says.In testing the new chip, the researchers showed that it can detect lead in water at concentrations as low as one part per billion. At much higher concentrations, which may be relevant for testing environmental contamination such as mine tailings, the accuracy is within 4 percent.The device works in water with varying levels of acidity, ranging from pH values of 6 to 8, “which covers most environmental samples,” Sia says. They have tested the device with seawater as well as tap water, and verified the accuracy of the measurements.In order to achieve such levels of accuracy, current testing requires a device called an inductive coupled plasma mass spectrometer. “These setups can be big and expensive,” Sia says. The sample processing can take days and requires experienced technical personnel.While the new chip system they developed is “the core part of the innovation,” Ranno says, further work will be needed to develop this into an integrated, handheld device for practical use. “For making an actual product, you would need to package it into a usable form factor,” he explains. This would involve having a small chip-based laser coupled to the photonic chip. “It’s a matter of mechanical design, some optical design, some chemistry, and figuring out the supply chain,” he says. While that takes time, he says, the underlying concepts are straightforward.The system can be adapted to detect other similar contaminants in water, including cadmium, copper, lithium, barium, cesium, and radium, Ranno says. The device could be used with simple cartridges that can be swapped out to detect different elements, each using slightly different crown ethers that can bind to a specific ion.“There’s this problem that people don’t measure their water enough, especially in the developing countries,” Ranno says. “And that’s because they need to collect the water, prepare the sample, and bring it to these huge instruments that are extremely expensive.” Instead, “having this handheld device, something compact that even untrained personnel can just bring to the source for on-site monitoring, at low costs,” could make regular, ongoing widespread testing feasible.Hu, who is the John F. Elliott Professor of Materials Science and Engineering, says, “I’m hoping this will be quickly implemented, so we can benefit human society. This is a good example of a technology coming from a lab innovation where it may actually make a very tangible impact on society, which is of course very fulfilling.”“If this study can be extended to simultaneous detection of multiple metal elements, especially the presently concerning radioactive elements, its potential would be immense,” says Hou Wang, an associate professor of environmental science and engineering at Hunan University in China, who was not associated with this work.Wang adds, “This research has engineered a sensor capable of instantaneously detecting lead concentration in water. This can be utilized in real-time to monitor the lead pollution concentration in wastewater discharged from industries such as battery manufacturing and lead smelting, facilitating the establishment of industrial wastewater monitoring systems. I think the innovative aspects and developmental potential of this research are quite commendable.”Wang Qian, a principal research scientist at the Institute of Materials Research in Singapore, who also was not affiliated with this work, says, “The ability for the pervasive, portable, and quantitative detection of lead has proved to be challenging primarily due to cost concerns. This work demonstrates the potential to do so in a highly integrated form factor and is compatible with large-scale, low-cost manufacturing.”The team included researchers at MIT, at Nanyang Technological University and Temasek Laboratories in Singapore, at the University of Southampton in the U.K., and at companies Fingate Technologies, in Singapore, and Vulcan Photonics, headquartered in Malaysia. The work used facilities at MIT.nano, the Harvard University Center for Nanoscale Systems, NTU’s Center for Micro- and Nano-Electronics, and the Nanyang Nanofabrication Center. More

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      in Environment

      Two MIT PhD students awarded J-WAFS fellowships for their research on water

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      Since 2014, the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) has advanced interdisciplinary research aimed at solving the world’s most pressing water and food security challenges to meet human needs. In 2017, J-WAFS established the Rasikbhai L. Meswani Water Solutions Fellowship and the J-WAFS Graduate Student Fellowship. These fellowships provide support to outstanding MIT graduate students who are pursuing research that has the potential to improve water and food systems around the world. Recently, J-WAFS awarded the 2024-25 fellowships to Jonathan Bessette and Akash Ball, two MIT PhD students dedicated to addressing water scarcity by enhancing desalination and purification processes. This work is of important relevance since the world’s freshwater supply has been steadily depleting due to the effects of climate change. In fact, one-third of the global population lacks access to safe drinking water. Bessette and Ball are focused on designing innovative solutions to enhance the resilience and sustainability of global water systems. To support their endeavors, J-WAFS will provide each recipient with funding for one academic semester for continued research and related activities.“This year, we received many strong fellowship applications,” says J-WAFS executive director Renee J. Robins. “Bessette and Ball both stood out, even in a very competitive pool of candidates. The award of the J-WAFS fellowships to these two students underscores our confidence in their potential to bring transformative solutions to global water challenges.”2024-25 Rasikbhai L. Meswani Fellowship for Water SolutionsThe Rasikbhai L. Meswani Fellowship for Water Solutions is a doctoral fellowship for students pursuing research related to water and water supply at MIT. The fellowship is made possible by Elina and Nikhil Meswani and family. Jonathan Bessette is a doctoral student in the Global Engineering and Research (GEAR) Center within the Department of Mechanical Engineering at MIT, advised by Professor Amos Winter. His research is focused on water treatment systems for the developing world, mainly desalination, or the process in which salts are removed from water. Currently, Bessette is working on designing and constructing a low-cost, deployable, community-scale desalination system for humanitarian crises.In arid and semi-arid regions, groundwater often serves as the sole water source, despite its common salinity issues. Many remote and developing areas lack reliable centralized power and water systems, making brackish groundwater desalination a vital, sustainable solution for global water scarcity. “An overlooked need for desalination is inland groundwater aquifers, rather than in coastal areas,” says Bessette. “This is because much of the population lives far enough from a coast that seawater desalination could never reach them. My work involves designing low-cost, sustainable, renewable-powered desalination technologies for highly constrained situations, such as drinking water for remote communities,” he adds.To achieve this goal, Bessette developed a batteryless, renewable electrodialysis desalination system. The technology is energy-efficient, conserves water, and is particularly suited for challenging environments, as it is decentralized and sustainable. The system offers significant advantages over the conventional reverse osmosis method, especially in terms of reduced energy consumption for treating brackish water. Highlighting Bessette’s capacity for engineering insight, his advisor noted the “simple and elegant solution” that Bessette and a staff engineer, Shane Pratt, devised that negated the need for the system to have large batteries. Bessette is now focusing on simplifying the system’s architecture to make it more reliable and cost-effective for deployment in remote areas.Growing up in upstate New York, Bessette completed a bachelor’s degree at the State University of New York at Buffalo. As an undergrad, he taught middle and high school students in low-income areas of Buffalo about engineering and sustainability. However, he cited his junior-year travel to India and his experience there measuring water contaminants in rural sites as cementing his dedication to a career addressing food, water, and sanitation challenges. In addition to his doctoral research, his commitment to these goals is further evidenced by another project he is pursuing, funded by a J-WAFS India grant, that uses low-cost, remote sensors to better understand water fetching practices. Bessette is conducting this work with fellow MIT student Gokul Sampath in order to help families in rural India gain access to safe drinking water.2024-25 J-WAFS Graduate Student Fellowship for Water and Food SolutionsThe J-WAFS Graduate Student Fellowship is supported by the J-WAFS Research Affiliate Program, which offers companies the opportunity to engage with MIT on water and food research. Current fellowship support was provided by two J-WAFS Research Affiliates: Xylem, a leading U.S.-based provider of water treatment and infrastructure solutions, and GoAigua, a Spanish company at the forefront of digital transformation in the water industry through innovative solutions. Akash Ball is a doctoral candidate in the Department of Chemical Engineering, advised by Professor Heather Kulik. His research focuses on the computational discovery of novel functional materials for energy-efficient ion separation membranes with high selectivity. Advanced membranes like these are increasingly needed for applications such as water desalination, battery recycling, and removal of heavy metals from industrial wastewater. “Climate change, water pollution, and scarce freshwater reserves cause severe water distress for about 4 billion people annually, with 2 billion in India and China’s semiarid regions,” Ball notes. “One potential solution to this global water predicament is the desalination of seawater, since seawater accounts for 97 percent of all water on Earth.”Although several commercial reverse osmosis membranes are currently available, these membranes suffer several problems, like slow water permeation, permeability-selectivity trade-off, and high fabrication costs. Metal-organic frameworks (MOFs) are porous crystalline materials that are promising candidates for highly selective ion separation with fast water transport due to high surface area, the presence of different pore windows, and the tunability of chemical functionality.In the Kulik lab, Ball is developing a systematic understanding of how MOF chemistry and pore geometry affect water transport and ion rejection rates. By the end of his PhD, Ball plans to identify existing, best-performing MOFs with unparalleled water uptake using machine learning models, propose novel hypothetical MOFs tailored to specific ion separations from water, and discover experimental design rules that enable the synthesis of next-generation membranes.  Ball’s advisor praised the creativity he brings to his research, and his leadership skills that benefit her whole lab. Before coming to MIT, Ball obtained a master’s degree in chemical engineering from the Indian Institute of Technology (IIT) Bombay and a bachelor’s degree in chemical engineering from Jadavpur University in India. During a research internship at IIT Bombay in 2018, he worked on developing a technology for in situ arsenic detection in water. Like Bessette, he noted the impact of this prior research experience on his interest in global water challenges, along with his personal experience growing up in an area in India where access to safe drinking water was not guaranteed. More

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      in Energy

      William Green named director of MIT Energy Initiative

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      MIT professor William H. Green has been named director of the MIT Energy Initiative (MITEI).In appointing Green, then-MIT Vice President for Research Maria Zuber highlighted his expertise in chemical kinetics — the understanding of the rates of chemical reactions — and the work of his research team in reaction kinetics, quantum chemistry, numerical methods, and fuel chemistry, as well as his work performing techno-economic assessments of proposed fuel and vehicle changes and biofuel production options.“Bill has been an active participant in MITEI; his broad view of energy science and technology will be a major asset and will position him well to contribute to the success of MIT’s exciting new Climate Project,” Zuber wrote in a letter announcing the appointment, which went into effect April 1. Green is the Hoyt C. Hottel Professor of Chemical Engineering and previously served as the executive officer of the MIT Department of Chemical Engineering from 2012 to 2015. He sees MITEI’s role today as bringing together the voices of engineering, science, industry, and policy to quickly drive the global energy transition.“MITEI has a very important role in fostering the energy and climate innovations happening at MIT and in building broader consensus, first in the engineering community and then ultimately to start the conversations that will lead to public acceptance and societal consensus,” says Green.Achieving consensus much more quickly is essential, says Green, who noted that it was during the 1992 Rio Summit that globally we recognized the problem of greenhouse gas emissions, yet almost a quarter-century passed before the Paris Agreement came into force. Eight years after the Paris Agreement, there is still disagreement over how to address this challenge in most sectors of the economy, and much work to be done to translate the Paris pledges into reality.“Many people feel we’re collectively too slow in dealing with the climate problem,” he says. “It’s very important to keep helping the research community be more effective and faster to provide the solutions that society needs, but we also need to work on being faster at reaching consensus around the good solutions we do have, and supporting them so they’ll actually be economically attractive so that investors can feel safe to invest in them, and to change regulations to make them feasible, when needed.”With experience in industry, policy, and academia, Green is well positioned to facilitate this acceleration. “I can see the situation from the point of view of a scientist, from the point of view of an engineer, from the point of view of the big companies, from the point of view of a startup company, and from the point of view of a parent concerned about the effects of climate change on the world my children are inheriting,” he says.Green also intends to extend MITEI’s engagement with a broader range of countries, industries, and economic sectors as MITEI focuses on decarbonization and accelerating the much-needed energy transition worldwide.Green received a PhD in physical chemistry from the University of California at Berkeley and a BA in chemistry from Swarthmore College. He joined MIT in 1997. He is the recipient of the AIChE’s R.H. Wilhelm Award in Chemical Reaction Engineering and is an inaugural Fellow of the Combustion Institute.He succeeds Robert Stoner, who served as interim director of MITEI beginning in July 2023, when longtime director Robert C. Armstrong retired after serving in the role for a decade. More