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      in Energy

      Shrinky Dinks, nail polish, and smelly bacteria

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      In a lab on the fourth floor of MIT’s Building 56, a group of Massachusetts high school students gathered around a device that measures conductivity.

      Vincent Nguyen, 15, from Saugus, thought of the times the material on their sample electrode flaked off the moment they took it out of the oven. Or how the electrode would fold weirdly onto itself. The big fails were kind of funny, but discouraging. The students had worked for a month, experimenting with different materials, and 17-year-old Brianna Tong of Malden wondered if they’d finally gotten it right: Would their electrode work well enough to power a microbial fuel cell?

      The students secured their electrode with alligator clips, someone hit start, and the teens watched anxiously as the device searched for even the faintest electrical current.

      Capturing electrons from bacteria

      Last July, Tong, Nguyen, and six other students from Malden Catholic High School commuted between the lab of MIT chemical engineer Ariel L. Furst and their school’s chemistry lab. Their goal was to fashion electrodes for low-cost microbial fuel cells — miniature bioreactors that generate small amounts of electricity by capturing electrons transferred from living microbes. These devices can double as electrochemical sensors.

      Furst, the Paul M. Cook Career Development Professor of Chemical Engineering, uses a mix of electrochemistry, microbial engineering, and materials science to address challenges in human health and clean energy. “The goal of all of our projects is to increase sustainability, clean energy, and health equity globally,” she says.

      Electrochemical sensors are powerful, sensitive detection and measurement tools. Typically, their electrodes need to be built in precisely engineered environments. “Thinking about ways of making devices without needing a cleanroom is important for coming up with inexpensive devices that can be deployed in low-resource settings under non-ideal conditions,” Furst says.

      For 17-year-old Angelina Ang of Everett, the project illuminated the significance of “coming together to problem-solve for a healthier and more sustainable earth,” she says. “It made me realize that we hold the answers to fix our dying planet.”

      With the help of a children’s toy called Shrinky Dinks, carbon-based materials, nail polish, and a certain smelly bacterium, the students got — literally — a trial-by-fire introduction to the scientific method. At one point, one of their experimental electrodes burst into flames. Other results were more promising.

      The students took advantage of the electrical properties of a bacterium — Shewanella oneidensis — that’s been called nature’s microscopic power plant. As part of their metabolism, Shewanella oneidensis generate electricity by oxidizing organic matter. In essence, they spit out electrons. Put enough together, and you get a few milliamps.

      To build bacteria-friendly electrodes, one of the first things the students did was culture Shewanella. They learned how to pour a growth medium into petri dishes where the reddish, normally lake-living bacteria could multiply. The microbes, Furst notes, are a little stinky, like cabbage. “But we think they’re really cool,” she says.

      With the right engineering, Shewanella can produce electric current when they detect toxins in water or soil. They could be used for bioremediation of wastewater. Low-cost versions could be useful for areas with limited or no access to reliable electricity and clean water.

      Next-generation chemists

      The Malden Catholic-MIT program resulted from a fluke encounter between Furst and a Malden Catholic parent.

      Mary-Margaret O’Donnell-Zablocki, then a medicinal chemist at a Kendall Square biotech startup, met Furst through a mutual friend. She asked Furst if she’d consider hosting high school chemistry students in her lab for the summer.

      Furst was intrigued. She traces her own passion for science to a program she’d happened upon between her junior and senior years in high school in St. Louis. The daughter of a software engineer and a businesswoman, Furst was casting around for potential career interests when she came across a summer program that enlisted scientists in academia and private research to introduce high school students and teachers to aspects of the scientific enterprise.

      “That’s when I realized that research is not like a lab class where there’s an expected outcome,” Furst recalls. “It’s so much cooler than that.”

      Using startup funding from an MIT Energy Initiative seed grant, Furst developed a curriculum with Malden Catholic chemistry teacher Seamus McGuire, and students were invited to apply. In addition to Tong, Ang, and Nguyen, participants included Chengxiang Lou, 18, from China; Christian Ogata, 14, of Wakefield; Kenneth Ramirez, 17, of Everett; Isaac Toscano, 17, of Medford; and MaryKatherine Zablocki, 15, of Revere and Wakefield. O’Donnell-Zablocki was surprised — and pleased — when her daughter applied to the program and was accepted.

      Furst notes that women are still underrepresented in chemical engineering. She was particularly excited to mentor young women through the program.

      A conductive ink

      The students were charged with identifying materials that had high conductivity, low resistance, were a bit soluble, and — with the help of a compatible “glue” — were able to stick to a substrate.

      Furst showed the Malden Catholic crew Shrinky Dinks — a common polymer popularized in the 1970s as a craft material that, when heated in a toaster oven, shrinks to a third of its size and becomes thicker and more rigid. Electrodes based on Shrinky Dinks would cost pennies, making it an ideal, inexpensive material for microbial fuel cells that could monitor, for instance, soil health in low- and middle-income countries.

      “Right now, monitoring soil health is problematic,” Furst says. “You have to collect a sample and bring it back to the lab to analyze in expensive equipment. But if we have these little devices that cost a couple of bucks each, we can monitor soil health remotely.”

      After a crash course in conductive carbon-based inks and solvent glues, the students went off to Malden Catholic to figure out what materials they wanted to try.

      Tong rattled them off: carbon nanotubes, carbon nanofibers, graphite powder, activated carbon. Potential solvents to help glue the carbon to the Shrinky Dinks included nail polish, corn syrup, and embossing ink, to name a few. They tested and retested. When they hit a dead end, they revised their hypotheses.

      They tried using a 3D printed stencil to daub the ink-glue mixture onto the Shrinky Dinks. They hand-painted them. They tried printing stickers. They worked with little squeegees. They tried scooping and dragging the material. Some of their electro-materials either flaked off or wouldn’t stick in the heating process.

      “Embossing ink never dried after baking the Shrinky Dink,” Ogata recalls. “In fact, it’s probably still liquid! And corn syrup had a tendency to boil. Seeing activated carbon ignite or corn syrup boiling in the convection oven was quite the spectacle.”

      “After the electrode was out of the oven and cooled down, we would check the conductivity,” says Tong, who plans to pursue a career in science. “If we saw there was a high conductivity, we got excited and thought those materials worked.”

      The moment of truth came in Furst’s MIT lab, where the students had access to more sophisticated testing equipment. Would their electrodes conduct electricity?

      Many of them didn’t. Tong says, “At first, we were sad, but then Dr. Furst told us that this is what science is, testing repeatedly and sometimes not getting the results we wanted.” Lou agrees. “If we just copy the data left by other scholars and don’t collect and figure it out by ourselves, then it is difficult to be a qualified researcher,” he says.

      Some of the students plan to continue the project one afternoon a week at MIT and as an independent study at Malden Catholic. The long-term goal is to create a field-based soil sensor that employs a bacterium like Shewanella.

      By chance, the students’ very first electrode — made of graphite powder ink and nail polish glue — generated the most current. One of the team’s biggest surprises was how much better black nail polish worked than clear nail polish. It turns out black nail polish contains iron-based pigment — a conductor. The unexpected win took some of the sting out of the failures.

      “They learned a very hard lesson: Your results might be awesome, and things are exciting, but then nothing else might work. And that’s totally fine,” Furst says.

      This article appears in the Winter 2023 issue of Energy Futures, the magazine of the MIT Energy Initiative. More

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      in Environment

      Nanotube sensors are capable of detecting and distinguishing gibberellin plant hormones

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      Researchers from the Disruptive and Sustainable Technologies for Agricultural Precision (DiSTAP) interdisciplinary research group of the Singapore-MIT Alliance for Research and Technology (SMART), MIT’s research enterprise in Singapore, and their collaborators from Temasek Life Sciences Laboratory have developed the first-ever nanosensor that can detect and distinguish gibberellins (GAs), a class of hormones in plants that are important for growth. The novel nanosensors are nondestructive, unlike conventional collection methods, and have been successfully tested in living plants. Applied in the field for early-stage plant stress monitoring, the sensors could prove transformative for agriculture and plant biotechnology, giving farmers interested in high-tech precision agriculture and crop management a valuable tool to optimize yield.

      The researchers designed near-infrared fluorescent carbon nanotube sensors that are capable of detecting and distinguishing two plant hormones, GA3 and GA4. Belonging to a class of plant hormones known as gibberellins, GA3 and GA4 are diterpenoid phytohormones produced by plants that play an important role in modulating diverse processes involved in plant growth and development. GAs are thought to have played a role in the driving forces behind the “green revolution” of the 1960s, which was in turn credited with averting famine and saving the lives of many worldwide. The continued study of gibberellins could lead to further breakthroughs in agricultural science and have implications for food security.

      Climate change, global warming, and rising sea levels cause farming soil to get contaminated by saltwater, raising soil salinity. In turn, high soil salinity is known to negatively regulate GA biosynthesis and promote GA metabolism, resulting in the reduction of GA content in plants. The new nanosensors developed by the SMART researchers allow for the study of GA dynamics in living plants under salinity stress at a very early stage, potentially enabling farmers to make early interventions when eventually applied in the field. This forms the basis of early-stage stress detection.

      Currently, methods to detect GA3 and GA4 typically require mass spectroscopy-based analysis, a time-consuming and destructive process. In contrast, the new sensors developed by the researchers are highly selective for the respective GAs and offer real-time, in vivo monitoring of changes in GA levels across a broad range of plant species.

      Described in a paper titled “Near-Infrared Fluorescent Carbon Nanotube Sensors for the Plant Hormone Family Gibberellins” published in the journal Nano Letters, the research represents a breakthrough for early-stage plant stress detection and holds tremendous potential to advance plant biotechnology and agriculture. This paper builds on previous research by the team at SMART DiSTAP on single-walled carbon nanotube-based nanosensors using the corona phase molecular recognition (CoPhMoRe) platform.

      Based on the CoPhMoRe concept introduced by the lab of MIT Professor Professor Michael Strano, the novel sensors are able to detect GA kinetics in the roots of a variety of model and non-model plant species, including Arabidopsis, lettuce, and basil, as well as GA accumulation during lateral root emergence, highlighting the importance of GA in root system architecture. This was made possible by the researchers’ related development of a new coupled Raman/near infrared fluorimeter that enables self-referencing of nanosensor near infrared fluorescence with its Raman G-band, a new hardware innovation that removes the need for a separate reference nanosensor and greatly simplifies the instrumentation requirements by using a single optical channel to measure hormone concentration.

      Using the reversible GA nanosensors, the researchers detected increased endogenous GA levels in mutant plants producing greater amounts of GA20ox1, a key enzyme in GA biosynthesis, as well as decreased GA levels in plants under salinity stress. When exposed to salinity stress, researchers also found that lettuce growth was severely stunted — an indication that only became apparent after 10 days. In contrast, the GA nanosensors reported decreased GA levels after just six hours, demonstrating their efficacy as a much earlier indicator of salinity stress.

      “Our CoPhMoRe technique allows us to create nanoparticles that act like natural antibodies in that they can recognize and lock onto specific molecules. But they tend to be far more stable than alternatives. We have used this method to successfully create nanosensors for plant signals such as hydrogen peroxide and heavy-metal pollutants like arsenic in plants and soil,” says Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT who is co-corresponding author and DiSTAP co-lead principal investigator. “The method works to create sensors for organic molecules like synthetic auxin — an important plant hormone — as we have shown. This latest breakthrough now extends this success to a plant hormone family called gibberellins — an exceedingly difficult one to recognize.”

      Strano adds: “The resulting technology offers a rapid, real-time, and in vivo method to monitor changes in GA levels in virtually any plant, and can replace current sensing methods which are laborious, destructive, species-specific, and much less efficient.”

      Mervin Chun-Yi Ang, associate scientific director at DiSTAP and co-first author of the paper, says, “More than simply a breakthrough in plant stress detection, we have also demonstrated a hardware innovation in the form of a new coupled Raman/NIR fluorimeter that enabled self-referencing of SWNT sensor fluorescence with its Raman G-band, representing a major advance in the translation of our nanosensing tool sets to the field. In the near future, our sensors can be combined with low-cost electronics, portable optodes, or microneedle interfaces for industrial use, transforming how the industry screens for and mitigates plant stress in food crops and potentially improving growth and yield.”

      The new sensors could yet have a variety of industrial applications and use cases. Daisuke Urano, a Temasek Life Sciences Laboratory principal investigator, National University of Singapore (NUS) adjunct assistant professor, and co-corresponding author of the paper, explains, “GAs are known to regulate a wide range of plant development processes, from shoot, root, and flower development, to seed germination and plant stress responses. With the commercialization of GAs, these plant hormones are also sold to growers and farmers as plant growth regulators to promote plant growth and seed germination. Our novel GA nanosensors could be applied in the field for early-stage plant stress monitoring, and also be used by growers and farmers to track the uptake or metabolism of GA in their crops.”

      The design and development of the nanosensors, creation and validation of the coupled Raman/near infrared fluorimeter and related image/data processing algorithms, as well as statistical analysis of readouts from plant sensors for this study were performed by SMART and MIT. The Temasek Life Sciences Laboratory was responsible for the design, execution, and analysis of plant-related studies, including validation of nanosensors in living plants.

      This research was carried out by SMART and supported by the National Research Foundation of Singapore under its Campus for Research Excellence And Technological Enterprise (CREATE) program. The DiSTAP program, led by Strano and Singapore co-lead principal investigator Professor Chua Nam Hai, addresses deep problems in food production in Singapore and the world by developing a suite of impactful and novel analytical, genetic, and biomaterial technologies. The goal is to fundamentally change how plant biosynthetic pathways are discovered, monitored, engineered, and ultimately translated to meet the global demand for food and nutrients. Scientists from MIT, Temasek Life Sciences Laboratory, Nanyang Technological University (NTU) and NUS are collaboratively developing new tools for the continuous measurement of important plant metabolites and hormones for novel discovery, deeper understanding and control of plant biosynthetic pathways in ways not yet possible, especially in the context of green leafy vegetables; leveraging these new techniques to engineer plants with highly desirable properties for global food security, including high yield density production, and drought and pathogen resistance, and applying these technologies to improve urban farming.

      SMART was established by MIT and the National Research Foundation of Singapore in 2007. SMART serves as an intellectual and innovation hub for research interactions between MIT and Singapore, undertaking cutting-edge research projects in areas of interest to both Singapore and MIT. SMART currently comprises an Innovation Center and five interdisciplinary research groups: Antimicrobial Resistance, Critical Analytics for Manufacturing Personalized-Medicine, DiSTAP, Future Urban Mobility, and Low Energy Electronic Systems. More

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      in Energy

      How to pull carbon dioxide out of seawater

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      As carbon dioxide continues to build up in the Earth’s atmosphere, research teams around the world have spent years seeking ways to remove the gas efficiently from the air. Meanwhile, the world’s number one “sink” for carbon dioxide from the atmosphere is the ocean, which soaks up some 30 to 40 percent of all of the gas produced by human activities.

      Recently, the possibility of removing carbon dioxide directly from ocean water has emerged as another promising possibility for mitigating CO2 emissions, one that could potentially someday even lead to overall net negative emissions. But, like air capture systems, the idea has not yet led to any widespread use, though there are a few companies attempting to enter this area.

      Now, a team of researchers at MIT says they may have found the key to a truly efficient and inexpensive removal mechanism. The findings were reported this week in the journal Energy and Environmental Science, in a paper by MIT professors T. Alan Hatton and Kripa Varanasi, postdoc Seoni Kim, and graduate students Michael Nitzsche, Simon Rufer, and Jack Lake.

      The existing methods for removing carbon dioxide from seawater apply a voltage across a stack of membranes to acidify a feed stream by water splitting. This converts bicarbonates in the water to molecules of CO2, which can then be removed under vacuum. Hatton, who is the Ralph Landau Professor of Chemical Engineering, notes that the membranes are expensive, and chemicals are required to drive the overall electrode reactions at either end of the stack, adding further to the expense and complexity of the processes. “We wanted to avoid the need for introducing chemicals to the anode and cathode half cells and to avoid the use of membranes if at all possible” he says.

      The team came up with a reversible process consisting of membrane-free electrochemical cells. Reactive electrodes are used to release protons to the seawater fed to the cells, driving the release of the dissolved carbon dioxide from the water. The process is cyclic: It first acidifies the water to convert dissolved inorganic bicarbonates to molecular carbon dioxide, which is collected as a gas under vacuum. Then, the water is fed to a second set of cells with a reversed voltage, to recover the protons and turn the acidic water back to alkaline before releasing it back to the sea. Periodically, the roles of the two cells are reversed once one set of electrodes is depleted of protons (during acidification) and the other has been regenerated during alkalization.

      This removal of carbon dioxide and reinjection of alkaline water could slowly start to reverse, at least locally, the acidification of the oceans that has been caused by carbon dioxide buildup, which in turn has threatened coral reefs and shellfish, says Varanasi, a professor of mechanical engineering. The reinjection of alkaline water could be done through dispersed outlets or far offshore to avoid a local spike of alkalinity that could disrupt ecosystems, they say.

      “We’re not going to be able to treat the entire planet’s emissions,” Varanasi says. But the reinjection might be done in some cases in places such as fish farms, which tend to acidify the water, so this could be a way of helping to counter that effect.

      Once the carbon dioxide is removed from the water, it still needs to be disposed of, as with other carbon removal processes. For example, it can be buried in deep geologic formations under the sea floor, or it can be chemically converted into a compound like ethanol, which can be used as a transportation fuel, or into other specialty chemicals. “You can certainly consider using the captured CO2 as a feedstock for chemicals or materials production, but you’re not going to be able to use all of it as a feedstock,” says Hatton. “You’ll run out of markets for all the products you produce, so no matter what, a significant amount of the captured CO2 will need to be buried underground.”

      Initially at least, the idea would be to couple such systems with existing or planned infrastructure that already processes seawater, such as desalination plants. “This system is scalable so that we could integrate it potentially into existing processes that are already processing ocean water or in contact with ocean water,” Varanasi says. There, the carbon dioxide removal could be a simple add-on to existing processes, which already return vast amounts of water to the sea, and it would not require consumables like chemical additives or membranes.

      “With desalination plants, you’re already pumping all the water, so why not co-locate there?” Varanasi says. “A bunch of capital costs associated with the way you move the water, and the permitting, all that could already be taken care of.”

      The system could also be implemented by ships that would process water as they travel, in order to help mitigate the significant contribution of ship traffic to overall emissions. There are already international mandates to lower shipping’s emissions, and “this could help shipping companies offset some of their emissions, and turn ships into ocean scrubbers,” Varanasi says.

      The system could also be implemented at locations such as offshore drilling platforms, or at aquaculture farms. Eventually, it could lead to a deployment of free-standing carbon removal plants distributed globally.

      The process could be more efficient than air-capture systems, Hatton says, because the concentration of carbon dioxide in seawater is more than 100 times greater than it is in air. In direct air-capture systems it is first necessary to capture and concentrate the gas before recovering it. “The oceans are large carbon sinks, however, so the capture step has already kind of been done for you,” he says. “There’s no capture step, only release.” That means the volumes of material that need to be handled are much smaller, potentially simplifying the whole process and reducing the footprint requirements.

      The research is continuing, with one goal being to find an alternative to the present step that requires a vacuum to remove the separated carbon dioxide from the water. Another need is to identify operating strategies to prevent precipitation of minerals that can foul the electrodes in the alkalinization cell, an inherent issue that reduces the overall efficiency in all reported approaches. Hatton notes that significant progress has been made on these issues, but that it is still too early to report on them. The team expects that the system could be ready for a practical demonstration project within about two years.

      “The carbon dioxide problem is the defining problem of our life, of our existence,” Varanasi says. “So clearly, we need all the help we can get.”

      The work was supported by ARPA-E. More

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      in Environment

      Rescuing small plastics from the waste stream

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      As plastic pollution continues to mount, with growing risks to ecosystems and wildlife, manufacturers are beginning to make ambitious commitments to keep new plastics out of the environment. A growing number have signed onto the U.S. Plastics Pact, which pledges to make 100 percent of plastic packaging reusable, recyclable, or compostable, and to see 50 percent of it effectively recycled or composted, by 2025.

      But for companies that make large numbers of small, disposable plastics, these pocket-sized objects are a major barrier to realizing their recycling goals.

      “Think about items like your toothbrush, your travel-size toothpaste tubes, your travel-size shampoo bottles,” says Alexis Hocken, a second-year PhD student in the MIT Department of Chemical Engineering. “They end up actually slipping through the cracks of current recycling infrastructure. So you might put them in your recycling bin at home, they might make it all the way to the sorting facility, but when it comes down to actually sorting them, they never make it into a recycled plastic bale at the very end of the line.”

      Now, a group of five consumer products companies is working with MIT to develop a sorting process that can keep their smallest plastic products inside the recycling chain. The companies — Colgate-Palmolive, Procter & Gamble, the Estée Lauder Companies, L’Oreal, and Haleon — all manufacture a large volume of “small format” plastics, or products less than two inches long in at least two dimensions. In a collaboration with Brad Olsen, the Alexander and I. Michael Kasser (1960) Professor of Chemical Engineering; Desiree Plata, an associate professor of civil and environmental engineering; the MIT Environmental Solutions Initiative; and the nonprofit The Sustainability Consortium, these companies are seeking a prototype sorting technology to bring to recycling facilities for large-scale testing and commercial development.

      Working in Olsen’s lab, Hocken is coming to grips with the complexity of the recycling systems involved. Material recovery facilities, or MRFs, are expected to handle products in any number of shapes, sizes, and materials, and sort them into a pure stream of glass, metal, paper, or plastic. Hocken’s first step in taking on the recycling project was to tour one of these MRFs in Portland, Maine, with Olsen and Plata.

      “We could literally see plastics just falling from the conveyor belts,” she says. “Leaving that tour, I thought, my gosh! There’s so much improvement that can be made. There’s so much impact that we can have on this industry.”

      From designing plastics to managing them

      Hocken always knew she wanted to work in engineering. Growing up in Scottsdale, Arizona, she was able to spend time in the workplace with her father, an electrical engineer who designs biomedical devices. “Seeing him working as an engineer, and how he’s solving these really important problems, definitely sparked my interest,” she says. “When it came time to begin my undergraduate degree, it was a really easy decision to choose engineering after seeing the day-to-day that my dad was doing in his career.”

      At Arizona State University, she settled on chemical engineering as a major and began working with polymers, coming up with combinations of additives for 3D plastics printing that could help fine-tune how the final products behaved. But even working with plastics every day, she rarely thought about the implications of her work for the environment.

      “And then in the spring of my final year at ASU, I took a class about polymers through the lens of sustainability, and that really opened my eyes,” Hocken remembers. The class was taught by Professor Timothy Long, director of the Biodesign Center for Sustainable Macromolecular Materials and Manufacturing and a well-known expert in the field of sustainable plastics. “That first session, where he laid out all of the really scary facts surrounding the plastics crisis, got me very motivated to look more into that field.”

      At MIT the next year, Hocken sought out Olsen as her advisor and made plastics sustainability her focus from the start.

      “Coming to MIT was my first time venturing outside of the state of Arizona for more than a three-month period,” she says. “It’s been really fun. I love living in Cambridge and the Boston area. I love my labmates. Everyone is so supportive, whether it’s to give me advice about some science that I’m trying to figure out, or just give me a pep talk if I’m feeling a little discouraged.”

      A challenge to recycle

      A lot of plastics research today is devoted to creating new materials — including biodegradable ones that are easier for natural ecosystems to absorb, and highly recyclable ones that hold their properties better after being melted down and recast.

      But Hocken also sees a huge need for better ways to handle the plastics we’re already making. “While biodegradable and sustainable polymers represent a very important route, and I think they should certainly be further pursued, we’re still a ways away from that being a reality universally across all plastic packaging,” she says. As long as large volumes of conventional plastic are coming out of factories, we’ll need innovative ways to stop it from piling onto the mountain of plastic pollution. In one of her projects, Hocken is trying to come up with new uses for recycled plastic that take advantage of its lost strength to produce a useful, flexible material similar to rubber.

      The small-format recycling project also falls in this category. The companies supporting the project have challenged the MIT team to work with their products exactly as currently manufactured — especially because their competitors use similar packaging materials that will also need to be covered by any solution the MIT team devises.

      The challenge is a large one. To kick the project off, the participating companies sent the MIT team a wide range of small-format products that need to make it through the sorting process. These include containers for lip balm, deodorant, pills, and shampoo, and disposable tools like toothbrushes and flossing picks. “A constraint, or problem I foresee, is just how variable the shapes are,” says Hocken. “A flossing pick versus a toothbrush are very different shapes.”

      Nor are they all made of the same kind of plastic. Many are made of polyethylene terephthalate (PET, type 1 in the recycling label system) or high-density polyethylene (HDPE, type 2), but nearly all of the seven recycling categories are represented among the sample products. The team’s solution will have to handle them all.

      Another obstacle is that the sorting process at a large MRF is already very complex and requires a heavy investment in equipment. The waste stream typically goes through a “glass breaker screen” that shatters glass and collects the shards; a series of rotating rubber stars to pull out two-dimensional objects, collecting paper and cardboard; a system of magnets and eddy currents to attract or repel different metals; and finally, a series of optical sorters that use infrared spectroscopy to identify the various types of plastics, then blow them down different chutes with jets of air. MRFs won’t be interested in adopting additional sorters unless they’re inexpensive and easy to fit into this elaborate stream.

      “We’re interested in creating something that could be retrofitted into current technology and current infrastructure,” Hocken says.

      Shared solutions

      “Recycling is a really good example of where pre-competitive collaboration is needed,” says Jennifer Park, collective action manager at The Sustainability Consortium (TSC), who has been working with corporate stakeholders on small format recyclability and helped convene the sponsors of this project and organize their contributions. “Companies manufacturing these products recognize that they cannot shift entire systems on their own. Consistency around what is and is not recyclable is the only way to avoid confusion and drive impact at scale.

      “Additionally, it is interesting that consumer packaged goods companies are sponsoring this research at MIT which is focused on MRF-level innovations. They’re investing in innovations that they hope will be adopted by the recycling industry to make progress on their own sustainability goals.”

      Hocken believes that, despite the challenges, it’s well worth pursuing a technology that can keep small-format plastics from slipping through MRFs’ fingers.

      “These are products that would be more recyclable if they were easier to sort,” she says. “The only thing that’s different is the size. So you can recycle both your large shampoo bottle and the small travel-size one at home, but the small one isn’t guaranteed to make it into a plastic bale at the end. If we can come up with a solution that specifically targets those while they’re still on the sorting line, they’re more likely to end up in those plastic bales at the end of the line, which can be sold to plastic reclaimers who can then use that material in new products.”

      “TSC is really excited about this project and our collaboration with MIT,” adds Park. “Our project stakeholders are very dedicated to finding a solution.”

      To learn more about this project, contact Christopher Noble, director of corporate engagement at the MIT Environmental Solutions Initiative. More

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      in Security

      Microparticles could help prevent vitamin A deficiency

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      Vitamin A deficiency is the world’s leading cause of childhood blindness, and in severe cases, it can be fatal. About one-third of the global population of preschool-aged children suffer from this vitamin deficiency, which is most prevalent in sub-Saharan Africa and South Asia.

      MIT researchers have now developed a new way to fortify foods with vitamin A, which they hope could help to improve the health of millions of people around the world. In a new study, they showed that encapsulating vitamin A in a protective polymer prevents the nutrient from being broken down during cooking or storage.

      “Vitamin A is a very important micronutrient, but it’s an unstable molecule,” says Ana Jaklenec, a research scientist at MIT’s Koch Institute for Integrative Cancer Research. “We wanted to see if our encapsulated vitamin A could fortify a food vehicle like bouillon cubes or flour, throughout storage and cooking, and whether the vitamin A could remain biologically active and be absorbed.”

      In a small clinical trial, the researchers showed that when people ate bread fortified with encapsulated vitamin A, the bioavailability of the nutrient was similar to when they consumed vitamin A on its own. The technology has been licensed to two companies that hope to develop it for use in food products.

      “This is a study that our team is really excited about because it shows that everything we did in test tubes and animals works safely and effectively in humans,” says Robert Langer, the David H. Koch Institute Professor at MIT and a member of the Koch Institute. “We hope this opens the door for someday helping millions, if not billions, of people in the developing world.”

      Jaklenec and Langer are the senior authors of the new study, which appears this week in the Proceedings of the National Academy of Sciences. The paper’s lead author is former MIT postdoc Wen Tang, who is now an associate professor at South China University of Technology.

      Nutrient stability

      Vitamin A is critical not only for vision but also the functioning of the immune system and organs such as the heart and lungs. Efforts to add vitamin A to bread or other foods such as bouillon cubes, which are commonly consumed in West African countries, have been largely unsuccessful because the vitamin breaks down during storage or cooking.

      In a 2019 study, the MIT team showed that they could use a polymer called BMC to encapsulate nutrients, including iron, vitamin A, and several others. They showed that this protective coating improved the shelf life of the nutrients, and that people who consumed bread fortified with encapsulated iron were able to absorb the iron.

      BMC is classified by the FDA as “generally regarded as safe,” and is already used in coatings for drugs and dietary supplements. In the new study, the researchers focused on using this polymer to encapsulate vitamin A, a nutrient that is very sensitive to temperature and ultraviolet light.

      Using an industrial process known as a spinning disc process, the researchers mixed vitamin A with the polymer to form particles 100 to 200 microns in diameter. They also coated the particles with starch, which prevents them from sticking to each other.

      The researchers found that vitamin A encapsulated in the polymer particles were more resistant to degradation by intense light, high temperatures, or boiling water. Under those conditions, much more vitamin A remained active than when the vitamin A was free or when it was delivered in a form called VitA 250, which is currently the most stable form of vitamin A used for food fortification.

      The researchers also showed that the encapsulated particles could be easily incorporated into flour or bouillon cubes. To test how well they would survive long-term storage, the researchers exposed the cubes to harsh conditions, as recommended by the World Health Organization: 40 degrees Celsius (104 degrees Fahrenheit) and 75 percent humidity. Under those conditions, the encapsulated vitamin A was much more stable than other forms of vitamin A. 

      “The enhanced stability of vitamin A with our technology can ensure that the vitamin A-fortified food does provide the recommended daily uptake of vitamin A, even after long-term storage in a hot humidified environment, and cooking processes such as boiling or baking,” Tang says. “People who are suffering from vitamin A deficiency and want to get vitamin A through fortified food will benefit, without changing their daily routines, and without wondering how much vitamin A is still in the food.”

      Vitamin absorption

      When the researchers cooked their encapsulated particles and then fed them to animals, they found that 30 percent of the vitamin A was absorbed, the same as free uncooked vitamin A, compared to about 3 percent of free vitamin A that had been cooked.

      Working with Biofortis, a company that does dietary clinical testing, the researchers then evaluated how well vitamin A was absorbed in people who ate foods fortified with the particles. For this study, the researchers incorporated the particles into bread, then measured vitamin A levels in the blood over a 24-hour period after the bread was consumed. They found that when vitamin A was encapsulated in the BMC polymer, it was absorbed from the food at levels comparable to free vitamin A, indicating that it is readily released in bioactive form.

      Two companies have licensed the technology and are focusing on developing products fortified with vitamin A and other nutrients. A benefit corporation called Particles for Humanity, funded by the Bill and Melinda Gates Foundation, is working with partners in Africa to incorporate this technology into existing fortification efforts. Another company called VitaKey, founded by Jaklenec, Langer, and others, is working on using this approach to add nutrients to a variety of foods and beverages.

      The research was funded by the Bill and Melinda Gates Foundation. Other authors of the paper include Jia Zhuang, Aaron Anselmo, Xian Xu, Aranda Duan, Ruojie Zhang, James Sugarman, Yingying Zeng, Evan Rosenberg, Tyler Graf, Kevin McHugh, Stephany Tzeng, Adam Behrens, Lisa Freed, Lihong Jing, Surangi Jayawardena, Shelley Weinstock, Xiao Le, Christopher Sears, James Oxley, John Daristotle, and Joe Collins. More

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      in Energy

      Reversing the charge

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      Owners of electric vehicles (EVs) are accustomed to plugging into charging stations at home and at work and filling up their batteries with electricity from the power grid. But someday soon, when these drivers plug in, their cars will also have the capacity to reverse the flow and send electrons back to the grid. As the number of EVs climbs, the fleet’s batteries could serve as a cost-effective, large-scale energy source, with potentially dramatic impacts on the energy transition, according to a new paper published by an MIT team in the journal Energy Advances.

      “At scale, vehicle-to-grid (V2G) can boost renewable energy growth, displacing the need for stationary energy storage and decreasing reliance on firm [always-on] generators, such as natural gas, that are traditionally used to balance wind and solar intermittency,” says Jim Owens, lead author and a doctoral student in the MIT Department of Chemical Engineering. Additional authors include Emre Gençer, a principal research scientist at the MIT Energy Initiative (MITEI), and Ian Miller, a research specialist for MITEI at the time of the study.

      The group’s work is the first comprehensive, systems-based analysis of future power systems, drawing on a novel mix of computational models integrating such factors as carbon emission goals, variable renewable energy (VRE) generation, and costs of building energy storage, production, and transmission infrastructure.

      “We explored not just how EVs could provide service back to the grid — thinking of these vehicles almost like energy storage on wheels — but also the value of V2G applications to the entire energy system and if EVs could reduce the cost of decarbonizing the power system,” says Gençer. “The results were surprising; I personally didn’t believe we’d have so much potential here.”

      Displacing new infrastructure

      As the United States and other nations pursue stringent goals to limit carbon emissions, electrification of transportation has taken off, with the rate of EV adoption rapidly accelerating. (Some projections show EVs supplanting internal combustion vehicles over the next 30 years.) With the rise of emission-free driving, though, there will be increased demand for energy. “The challenge is ensuring both that there’s enough electricity to charge the vehicles and that this electricity is coming from renewable sources,” says Gençer.

      But solar and wind energy is intermittent. Without adequate backup for these sources, such as stationary energy storage facilities using lithium-ion batteries, for instance, or large-scale, natural gas- or hydrogen-fueled power plants, achieving clean energy goals will prove elusive. More vexing, costs for building the necessary new energy infrastructure runs to the hundreds of billions.

      This is precisely where V2G can play a critical, and welcome, role, the researchers reported. In their case study of a theoretical New England power system meeting strict carbon constraints, for instance, the team found that participation from just 13.9 percent of the region’s 8 million light-duty (passenger) EVs displaced 14.7 gigawatts of stationary energy storage. This added up to $700 million in savings — the anticipated costs of building new storage capacity.

      Their paper also described the role EV batteries could play at times of peak demand, such as hot summer days. “V2G technology has the ability to inject electricity back into the system to cover these episodes, so we don’t need to install or invest in additional natural gas turbines,” says Owens. “The way that EVs and V2G can influence the future of our power systems is one of the most exciting and novel aspects of our study.”

      Modeling power

      To investigate the impacts of V2G on their hypothetical New England power system, the researchers integrated their EV travel and V2G service models with two of MITEI’s existing modeling tools: the Sustainable Energy System Analysis Modeling Environment (SESAME) to project vehicle fleet and electricity demand growth, and GenX, which models the investment and operation costs of electricity generation, storage, and transmission systems. They incorporated such inputs as different EV participation rates, costs of generation for conventional and renewable power suppliers, charging infrastructure upgrades, travel demand for vehicles, changes in electricity demand, and EV battery costs.

      Their analysis found benefits from V2G applications in power systems (in terms of displacing energy storage and firm generation) at all levels of carbon emission restrictions, including one with no emissions caps at all. However, their models suggest that V2G delivers the greatest value to the power system when carbon constraints are most aggressive — at 10 grams of carbon dioxide per kilowatt hour load. Total system savings from V2G ranged from $183 million to $1,326 million, reflecting EV participation rates between 5 percent and 80 percent.

      “Our study has begun to uncover the inherent value V2G has for a future power system, demonstrating that there is a lot of money we can save that would otherwise be spent on storage and firm generation,” says Owens.

      Harnessing V2G

      For scientists seeking ways to decarbonize the economy, the vision of millions of EVs parked in garages or in office spaces and plugged into the grid for 90 percent of their operating lives proves an irresistible provocation. “There is all this storage sitting right there, a huge available capacity that will only grow, and it is wasted unless we take full advantage of it,” says Gençer.

      This is not a distant prospect. Startup companies are currently testing software that would allow two-way communication between EVs and grid operators or other entities. With the right algorithms, EVs would charge from and dispatch energy to the grid according to profiles tailored to each car owner’s needs, never depleting the battery and endangering a commute.

      “We don’t assume all vehicles will be available to send energy back to the grid at the same time, at 6 p.m. for instance, when most commuters return home in the early evening,” says Gençer. He believes that the vastly varied schedules of EV drivers will make enough battery power available to cover spikes in electricity use over an average 24-hour period. And there are other potential sources of battery power down the road, such as electric school buses that are employed only for short stints during the day and then sit idle.

      The MIT team acknowledges the challenges of V2G consumer buy-in. While EV owners relish a clean, green drive, they may not be as enthusiastic handing over access to their car’s battery to a utility or an aggregator working with power system operators. Policies and incentives would help.

      “Since you’re providing a service to the grid, much as solar panel users do, you could be paid for your participation, and paid at a premium when electricity prices are very high,” says Gençer.

      “People may not be willing to participate ’round the clock, but if we have blackout scenarios like in Texas last year, or hot-day congestion on transmission lines, maybe we can turn on these vehicles for 24 to 48 hours, sending energy back to the system,” adds Owens. “If there’s a power outage and people wave a bunch of money at you, you might be willing to talk.”

      “Basically, I think this comes back to all of us being in this together, right?” says Gençer. “As you contribute to society by giving this service to the grid, you will get the full benefit of reducing system costs, and also help to decarbonize the system faster and to a greater extent.”

      Actionable insights

      Owens, who is building his dissertation on V2G research, is now investigating the potential impact of heavy-duty electric vehicles in decarbonizing the power system. “The last-mile delivery trucks of companies like Amazon and FedEx are likely to be the earliest adopters of EVs,” Owen says. “They are appealing because they have regularly scheduled routes during the day and go back to the depot at night, which makes them very useful for providing electricity and balancing services in the power system.”

      Owens is committed to “providing insights that are actionable by system planners, operators, and to a certain extent, investors,” he says. His work might come into play in determining what kind of charging infrastructure should be built, and where.

      “Our analysis is really timely because the EV market has not yet been developed,” says Gençer. “This means we can share our insights with vehicle manufacturers and system operators — potentially influencing them to invest in V2G technologies, avoiding the costs of building utility-scale storage, and enabling the transition to a cleaner future. It’s a huge win, within our grasp.”

      The research for this study was funded by MITEI’s Future Energy Systems Center. More

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      in Energy

      On batteries, teaching, and world peace

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      Over his long career as an electrochemist and professor, Donald Sadoway has earned an impressive variety of honors, from being named one of Time magazine’s 100 most influential people in 2012 to appearing on “The Colbert Report,” where he talked about “renewable energy and world peace,” according to Comedy Central.

      What does he personally consider to be his top achievements?

      “That’s easy,” he says immediately. “For teaching, it’s 3.091,” the MIT course on solid-state chemistry he led for some 18 years. An MIT core requirement, 3.091 is also one of the largest classes at the Institute. In 2003 it was the largest, with 630 students. Sadoway, who retires this year after 45 years in the Department of Materials Science and Engineering, estimates that over the years he’s taught the course to some 10,000 undergraduates.

      A passion for teaching

      Along the way he turned the class into an MIT favorite, complete with music, art, and literature. “I brought in all that enrichment because I knew that 95 percent of the students in that room weren’t going to major in anything chemical and this might be the last class they’d take in the subject. But it’s a requirement. So they’re 18 years old, they’re very smart, and many of them are very bored. You have to find a hook [to reach them]. And I did.”

      In 1995, Sadoway was named a Margaret MacVicar Faculty Fellow, an honor that recognizes outstanding classroom teaching at the Institute. Among the communications in support of his nomination:

      “His contributions are enormous and the class is in rapt attention from beginning to end. His lectures are highly articulate yet animated and he has uncommon grace and style. I was awed by his ability to introduce playful and creative elements into a core lecture…”

      Bill Gates would agree. In the early 2000s Sadoway’s lectures were shared with the world through OpenCourseWare, the web-based publication of MIT course materials. Gates was so inspired by the lectures that he asked to meet with Sadoway to learn more about his research. (Sadoway initially ignored Gates’ email because he thought his account had been hacked by MIT pranksters.)

      Research breakthroughs

      Teaching is not Sadoway’s only passion. He’s also proud of his accomplishments in electrochemistry. The discipline that involves electron transfer reactions is key to everything from batteries to the primary extraction of metals like aluminum and magnesium. “It’s quite wide-ranging,” says the John F. Elliott Professor Emeritus of Materials Chemistry.

      Sadoway’s contributions include two battery breakthroughs. First came the liquid metal battery, which could enable the large-scale storage of renewable energy. “That represents a huge step forward in the transition to green energy,” said António Campinos, president of the European Patent Office, earlier this year when Sadoway won the 2022 European Inventor Award for the invention in the category for Non-European Patent Office Countries.

      On “The Colbert Report,” Sadoway alluded to that work when he told Stephen Colbert that electrochemistry is the key to world peace. Why? Because it could lead to a battery capable of storing energy from the sun when the sun doesn’t shine and otherwise make renewables an important part of the clean energy mix. And that in turn could “plummet the price of petroleum and depose dictators all over the world without one shot being fired,” he recently recalled.

      The liquid metal battery is the focus of Ambri, one of six companies based on Sadoway’s inventions. Bill Gates was the first funder of the company, which formed in 2010 and aims to install its first battery soon. That battery will store energy from a reported 500 megawatts of on-site renewable generation, the same output as a natural gas power plant.

      Then, in August of this year, Sadoway and colleagues published a paper in Nature about “one of the first new battery chemistries in 30 years,” Sadoway says. “I wanted to invent something that was better, much better,” than the expensive lithium-ion batteries used in, for example, today’s electric cars.

      That battery is the focus of Avanti, one of three Sadoway companies formed just last year. The other two are Pure Lithium, to commercialize his inventions related to that element, and Sadoway Labs. The latter, a nonprofit, is essentially “a space to try radical innovations. We’re gonna start working on wild ideas.”

      Another focus of Sadoway’s research: green steel. Steelmaking produces huge amounts of greenhouse gases. Enter Boston Metal, another Sadoway company. This one is developing a new approach to producing steel based on research begun some 25 years ago. Unlike the current technology for producing steel, the Boston Metal approach — molten oxide electrolysis — does not use the element at the root of steel’s problems: carbon. The principal byproduct of the new system? Oxygen.

      In 2012, Sadoway gave a TED talk to 2,000 people on the liquid metal battery. He believes that that talk, which has now been seen by almost 2.5 million people, led to the wider publicity of his work — and science overall — on “The Colbert Report” and elsewhere. “The moral here is that if you step out of your comfort zone, you might be surprised at what can happen,” he concludes.

      Colleagues’ reflections

      “I met Don in 2006 when I was working for the iron and steel industry in Europe on ways to reduce greenhouse gas emissions from the production of those materials,” says Antoine Allanore, professor of metallurgy, Department of Materials Science and Engineering. “He was the same Don Sadoway that you see in recordings of his lectures: very elegant, very charismatic, and passionate about the technical solutions and underlying science of the process we were all investigating; electrolysis. A few years later, when I decided to pursue an academic career, I contacted Don and became a postdoctoral associate in his lab. That ultimately led to my becoming an MIT professor. People don’t believe me, but before I came to MIT the only thing I knew about the Institute was that Noam Chomsky was there … and Don Sadoway. And I felt, that’s a great place to be. And I stayed because I saw the exceptional things that can be accomplished at MIT and Don is the perfect example of that.”

      “I had the joy of meeting Don when I first arrived on the MIT campus in 1994,” recalls Felice Frankel, research scientist in the MIT departments of Chemical Engineering and Mechanical Engineering. “I didn’t have to talk him into the idea that researchers needed to take their images and graphics more seriously.  He got it — that it wasn’t just about pretty pictures. He was an important part of our five-year National Science Foundation project — Picturing to Learn — to bring that concept into the classroom. How lucky that was for me!”

      “Don has been a friend and mentor since we met in 1995 when I was an MIT senior,” says Luis Ortiz, co-founder and chief executive officer, Avanti Battery Co. “One story that is emblematic of Don’s insistence on excellence is from when he and I met with Bill Gates about the challenges in addressing climate change and how batteries could be the linchpin in solving them. I suggested that we create our presentation in PowerPoint [Microsoft software]. Don balked. He insisted that we present using Keynote on his MacBook Air, because ‘it looks so much better.’ I was incredulous that he wanted to walk into that venue exclusively using Apple products. Of course, he won the argument, but not without my admonition that there had better not be even a blip of an issue. In the meeting room, Microsoft’s former chief technology officer asked Don if he needed anything to hook up to the screen, ‘we have all those dongles.’ Don declined, but gave me that knowing look and whispered, ‘You see, they know, too.’ I ate my crow and we had a great long conversation without any issues.”

      “I remember when I first started working with Don on the liquid metal battery project at MIT, after I had chosen it as the topic for my master’s of engineering thesis,” adds David Bradwell, co-founder and chief technology officer, Ambri. “I was a wide-eyed graduate student, sitting in his office, amongst his art deco decorations, unique furniture, and historical and stylistic infographics, and from our first meeting, I could see Don’s passion for coming up with new and creative, yet practical scientific ideas, and for working on hard problems, in service of society. Don’s approaches always appear to be unconventional — wanting to stand out in a crowd, take the path less trodden, both based on his ideas, and his sense of style. It’s been an amazing journey working with him over the past decade-and-a-half, and I remain excited to see what other new, unconventional ideas, he can bring to this world.” More

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      in Environment

      MIT PhD students shed light on important water and food research

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      One glance at the news lately will reveal countless headlines on the dire state of global water and food security. Pollution, supply chain disruptions, and the war in Ukraine are all threatening water and food systems, compounding climate change impacts from heat waves, drought, floods, and wildfires.

      Every year, MIT’s Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) offers fellowships to outstanding MIT graduate students who are working on innovative ways to secure water and food supplies in light of these urgent worldwide threats. J-WAFS announced this year’s fellowship recipients last April. Aditya Ghodgaonkar and Devashish Gokhale were awarded Rasikbhai L. Meswani Fellowships for Water Solutions, which are made possible by a generous gift from Elina and Nikhil Meswani and family. James Zhang, Katharina Fransen, and Linzixuan (Rhoda) Zhang were awarded J-WAFS Fellowships for Water and Food Solutions. The J-WAFS Fellowship for Water and Food Solutions is funded in part by J-WAFS Research Affiliate companies: Xylem, Inc., a water technology company, and GoAigua, a company leading the digital transformation of the water industry.

      The five fellows were each awarded a stipend and full tuition for one semester. They also benefit from mentorship, networking connections, and opportunities to showcase their research.

      “This year’s cohort of J-WAFS fellows show an indefatigable drive to explore, create, and push back boundaries,” says John H. Lienhard, director of J-WAFS. “Their passion and determination to create positive change for humanity are evident in these unique video portraits, which describe their solutions-oriented research in water and food,” Lienhard adds.

      J-WAFS funder Community Jameel recently commissioned video portraitures of each student that highlight their work and their inspiration to solve challenges in water and food. More about each J-WAFS fellow and their research follows.

      Play video

      Katharina Fransen

      In Professor Bradley Olsen’s lab in the Department of Chemical Engineering, Katharina Fransen works to develop biologically-based, biodegradable plastics which can be used for food packing that won’t pollute the environment. Fransen, a third-year PhD student, is motivated by the challenge of protecting the most vulnerable global communities from waste generated by the materials that are essential to connecting them to the global food supply. “We can’t ensure that all of our plastic waste gets recycled or reused, and so we want to make sure that if it does escape into the environment it can degrade, and that’s kind of where a lot of my research really comes in,” says Fransen. Most of her work involves creating polymers, or “really long chains of chemicals,” kind of like the paper rings a lot of us looped into chains as kids, Fransen explains. The polymers are optimized for food packaging applications to keep food fresher for longer, preventing food waste. Fransen says she finds the work “really interesting from the scientific perspective as well as from the idea that [she’s] going to make the world a little better with these new materials.” She adds, “I think it is both really fulfilling and really exciting and engaging.”

      Play video

      Aditya Ghodgaonkar

      “When I went to Kenya this past spring break, I had an opportunity to meet a lot of farmers and talk to them about what kind of maintenance issues they face,” says Aditya Ghodgaonkar, PhD candidate in the Department of Mechanical Engineering. Ghodgaonkar works with Associate Professor Amos Winter in the Global Engineering and Research (GEAR) Lab, where he designs hydraulic components for drip irrigation systems to make them water-efficient, off-grid, inexpensive, and low-maintenance. On his trip to Kenya, Ghodgaonkar gained firsthand knowledge from farmers about a common problem they encounter: clogging of drip irrigation emitters. He learned that clogging can be an expensive technical challenge to diagnose, mitigate, and resolve. He decided to focus his attention on designing emitters that are resistant to clogging, testing with sand and passive hydrodynamic filtration back in the lab at MIT. “I got into this from an academic standpoint,” says Ghodgaonkar. “It is only once I started working on the emitters, spoke with industrial partners that make these emitters, spoke with farmers, that I really truly appreciated the impact of what we’re doing.”

      Play video

      Devashish Gokhale

      Devashish Gokhale is a PhD student advised by Professor Patrick Doyle in the Department of Chemical Engineering. Gokhale’s commitment to global water security stems from his childhood in Pune, India, where both flooding and drought can occur depending on the time of year. “I’ve had these experiences where there’s been too much water and also too little water” he recalls. At MIT, Gokhale is developing cost-effective, sustainable, and reusable materials for water treatment with a focus on the elimination of emerging contaminants and low-concentration pollutants like heavy metals. Specifically, he works on making and optimizing polymeric hydrogel microparticles that can absorb micropollutants. “I know how important it is to do something which is not just scientifically interesting, but something which is impactful in a real way,” says Gokhale. Before starting a research project he asks himself, “are people going to be able to afford this? Is it really going to reach the people who need it the most?” Adding these constraints in the beginning of the research process sometimes makes the problem more difficult to solve, but Gokhale notes that in the end, the solution is much more promising.

      Play video

      James Zhang

      “We don’t really think much about it, it’s transparent, odorless, we just turn on our sink in many parts of the world and it just flows through,” says James Zhang when talking about water. Yet he notes that “many other parts of the world face water scarcity and this will only get worse due to global climate change.” A PhD student in the Department of Mechanical Engineering, Zhang works in the Nano Engineering Laboratory with Professor Gang Chen. Zhang is working on a technology that uses light-induced evaporation to clean water. He is currently investigating the fundamental properties of how light at different wavelengths interacts with liquids at the surface, particularly with brackish water surfaces. With strong theoretical and experimental components, his research could lead to innovations in desalinating water at high energy efficiencies. Zhang hopes that the technology can one day “produce lots of clean water for communities around the world that currently don’t have access to fresh water,” and create a new appreciation for this common liquid that many of us might not think about on a day-to-day basis.

      Play video

      Linzixuan (Rhoda) Zhang

      “Around the world there are about 2 billion people currently suffering from micronutrient deficiency because they do not have access to very healthy, very fresh food,” says chemical engineering PhD candidate Linzixuan (Rhoda) Zhang. This fact led Zhang to develop a micronutrient delivery platform that fortifies foods with essential vitamins and nutrients. With her advisors, Professor Robert Langer and Research Scientist Ana Jaklenec, Zhang brings biomedical engineering approaches to global health issues. Zhang says that “one of the most serious problems is vitamin A deficiency, because vitamin A is not very stable.” She goes on to explain that although vitamin A is present in different vegetables, when the vegetables are cooked, vitamin A can easily degrade. Zhang helped develop a group of biodegradable polymers that can stabilize micronutrients under cooking and storage conditions. With this technology, vitamin A, for example, could be encapsulated and effectively stabilized under boiling water. The platform has also shown efficient release in a simulation of the stomach environment. Zhang says it is the “little, tiny steps every day that are pushing us forward to the final impactful product.” More