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      New process could enable more efficient plastics recycling

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      The accumulation of plastic waste in the oceans, soil, and even in our bodies is one of the major pollution issues of modern times, with over 5 billion tons disposed of so far. Despite major efforts to recycle plastic products, actually making use of that motley mix of materials has remained a challenging issue.

      A key problem is that plastics come in so many different varieties, and chemical processes for breaking them down into a form that can be reused in some way tend to be very specific to each type of plastic. Sorting the hodgepodge of waste material, from soda bottles to detergent jugs to plastic toys, is impractical at large scale. Today, much of the plastic material gathered through recycling programs ends up in landfills anyway. Surely there’s a better way.

      According to new research from MIT and elsewhere, it appears there may indeed be a much better way. A chemical process using a catalyst based on cobalt has been found to be very effective at breaking down a variety of plastics, such as polyethylene (PET) and polypropylene (PP), the two most widely produced forms of plastic, into a single product, propane. Propane can then be used as a fuel for stoves, heaters, and vehicles, or as a feedstock for the production of a wide variety of products — including new plastics, thus potentially providing at least a partial closed-loop recycling system.

      The finding is described today in the open access journal  JACS Au, in a paper by MIT professor of chemical engineering Yuriy Román-Leshkov, postdoc Guido Zichitella, and seven others at MIT, the SLAC National Accelerator Laboratory, and the National Renewable Energy Laboratory.

      Recycling plastics has been a thorny problem, Román-Leshkov explains, because the long-chain molecules in plastics are held together by carbon bonds, which are “very stable and difficult to break apart.” Existing techniques for breaking these bonds tend to produce a random mix of different molecules, which would then require complex refining methods to separate out into usable specific compounds. “The problem is,” he says, “there’s no way to control where in the carbon chain you break the molecule.”

      But to the surprise of the researchers, a catalyst made of a microporous material called a zeolite that contains cobalt nanoparticles can selectively break down various plastic polymer molecules and turn more than 80 percent of them into propane.

      Although zeolites are riddled with tiny pores less than a nanometer wide (corresponding to the width of the polymer chains), a logical assumption had been that there would be little interaction at all between the zeolite and the polymers. Surprisingly, however, the opposite turned out to be the case: Not only do the polymer chains enter the pores, but the synergistic work between cobalt and the acid sites in the zeolite can break the chain at the same point. That cleavage site turned out to correspond to chopping off exactly one propane molecule without generating unwanted methane, leaving the rest of the longer hydrocarbons ready to undergo the process, again and again.

      “Once you have this one compound, propane, you lessen the burden on downstream separations,” Román-Leshkov says. “That’s the essence of why we think this is quite important. We’re not only breaking the bonds, but we’re generating mainly a single product” that can be used for many different products and processes.

      The materials needed for the process, zeolites and cobalt, “are both quite cheap” and widely available, he says, although today most cobalt comes from troubled areas in the Democratic Republic of Congo. Some new production is being developed in Canada, Cuba, and other places. The other material needed for the process is hydrogen, which today is mostly produced from fossil fuels but can easily be made other ways, including electrolysis of water using carbon-free electricity such as solar or wind power.

      The researchers tested their system on a real example of mixed recycled plastic, producing promising results. But more testing will be needed on a greater variety of mixed waste streams to determine how much fouling takes place from various contaminants in the material — such as inks, glues, and labels attached to the plastic containers, or other nonplastic materials that get mixed in with the waste — and how that affects the long-term stability of the process.

      Together with collaborators at NREL, the MIT team is also continuing to study the economics of the system, and analyzing how it can fit into today’s systems for handling plastic and mixed waste streams. “We don’t have all the answers yet,” Román-Leshkov says, but preliminary analysis looks promising.

      The research team included Amani Ebrahim and Simone Bare at the SLAC National Accelerator Laboratory; Jie Zhu, Anna Brenner, Griffin Drake and Julie Rorrer at MIT; and Greg Beckham at the National Renewable Energy Laboratory. The work was supported by the U.S. Department of Energy (DoE), the Swiss National Science Foundation, and the DoE’s Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Office (AMO), and Bioenergy Technologies Office (BETO), as part of the the Bio-Optimized Technologies to keep Thermoplastics out of Landfills and the Environment (BOTTLE) Consortium. More

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      Processing waste biomass to reduce airborne emissions

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      To prepare fields for planting, farmers the world over often burn corn stalks, rice husks, hay, straw, and other waste left behind from the previous harvest. In many places, the practice creates huge seasonal clouds of smog, contributing to air pollution that kills 7 million people globally a year, according to the World Health Organization.

      Annually, $120 billion worth of crop and forest residues are burned in the open worldwide — a major waste of resources in an energy-starved world, says Kevin Kung SM ’13, PhD ’17. Kung is working to transform this waste biomass into marketable products — and capitalize on a billion-dollar global market — through his MIT spinoff company, Takachar.

      Founded in 2015, Takachar develops small-scale, low-cost, portable equipment to convert waste biomass into solid fuel using a variety of thermochemical treatments, including one known as oxygen-lean torrefaction. The technology emerged from Kung’s PhD project in the lab of Ahmed Ghoniem, the Ronald C. Crane (1972) Professor of Mechanical Engineering at MIT.

      Biomass fuels, including wood, peat, and animal dung, are a major source of carbon emissions — but billions of people rely on such fuels for cooking, heating, and other household needs. “Currently, burning biomass generates 10 percent of the primary energy used worldwide, and the process is used largely in rural, energy-poor communities. We’re not going to change that overnight. There are places with no other sources of energy,” Ghoniem says.

      What Takachar’s technology provides is a way to use biomass more cleanly and efficiently by concentrating the fuel and eliminating contaminants such as moisture and dirt, thus creating a “clean-burning” fuel — one that generates less smoke. “In rural communities where biomass is used extensively as a primary energy source, torrefaction will address air pollution head-on,” Ghoniem says.

      Thermochemical treatment densifies biomass at elevated temperatures, converting plant materials that are typically loose, wet, and bulky into compact charcoal. Centralized processing plants exist, but collection and transportation present major barriers to utilization, Kung says. Takachar’s solution moves processing into the field: To date, Takachar has worked with about 5,500 farmers to process 9,000 metric tons of crops.

      Takachar estimates its technology has the potential to reduce carbon dioxide equivalent emissions by gigatons per year at scale. (“Carbon dioxide equivalent” is a measure used to gauge global warming potential.) In recognition, in 2021 Takachar won the first-ever Earthshot Prize in the clean air category, a £1 million prize funded by Prince William and Princess Kate’s Royal Foundation.

      Roots in Kenya

      As Kung tells the story, Takachar emerged from a class project that took him to Kenya — which explains the company’s name, a combination of takataka, which mean “trash” in Swahili, and char, for the charcoal end product.

      It was 2011, and Kung was at MIT as a biological engineering grad student focused on cancer research. But “MIT gives students big latitude for exploration, and I took courses outside my department,” he says. In spring 2011, he signed up for a class known as 15.966 (Global Health Delivery Lab) in the MIT Sloan School of Management. The class brought Kung to Kenya to work with a nongovernmental organization in Nairobi’s Kibera, the largest urban slum in Africa.

      “We interviewed slum households for their views on health, and that’s when I noticed the charcoal problem,” Kung says. The problem, as Kung describes it, was that charcoal was everywhere in Kibera — piled up outside, traded by the road, and used as the primary fuel, even indoors. Its creation contributed to deforestation, and its smoke presented a serious health hazard.

      Eager to address this challenge, Kung secured fellowship support from the MIT International Development Initiative and the Priscilla King Gray Public Service Center to conduct more research in Kenya. In 2012, he formed Takachar as a team and received seed money from the MIT IDEAS Global Challenge, MIT Legatum Center for Development and Entrepreneurship, and D-Lab to produce charcoal from household organic waste. (This work also led to a fertilizer company, Safi Organics, that Kung founded in 2016 with the help of MIT IDEAS. But that is another story.)

      Meanwhile, Kung had another top priority: finding a topic for his PhD dissertation. Back at MIT, he met Alexander Slocum, the Walter M. May and A. Hazel May Professor of Mechanical Engineering, who on a long walk-and-talk along the Charles River suggested he turn his Kenya work into a thesis. Slocum connected him with Robert Stoner, deputy director for science and technology at the MIT Energy Initiative (MITEI) and founding director of MITEI’s Tata Center for Technology and Design. Stoner in turn introduced Kung to Ghoniem, who became his PhD advisor, while Slocum and Stoner joined his doctoral committee.

      Roots in MIT lab

      Ghoniem’s telling of the Takachar story begins, not surprisingly, in the lab. Back in 2010, he had a master’s student interested in renewable energy, and he suggested the student investigate biomass. That student, Richard Bates ’10, SM ’12, PhD ’16, began exploring the science of converting biomass to more clean-burning charcoal through torrefaction.

      Most torrefaction (also known as low-temperature pyrolysis) systems use external heating sources, but the lab’s goal, Ghoniem explains, was to develop an efficient, self-sustained reactor that would generate fewer emissions. “We needed to understand the chemistry and physics of the process, and develop fundamental scaling models, before going to the lab to build the device,” he says.

      By the time Kung joined the lab in 2013, Ghoniem was working with the Tata Center to identify technology suitable for developing countries and largely based on renewable energy. Kung was able to secure a Tata Fellowship and — building on Bates’ research — develop the small-scale, practical device for biomass thermochemical conversion in the field that launched Takachar.

      This device, which was patented by MIT with inventors Kung, Ghoniem, Stoner, MIT research scientist Santosh Shanbhogue, and Slocum, is self-contained and scalable. It burns a little of the biomass to generate heat; this heat bakes the rest of the biomass, releasing gases; the system then introduces air to enable these gases to combust, which burns off the volatiles and generates more heat, keeping the thermochemical reaction going.

      “The trick is how to introduce the right amount of air at the right location to sustain the process,” Ghoniem explains. “If you put in more air, that will burn the biomass. If you put in less, there won’t be enough heat to produce the charcoal. That will stop the reaction.”

      About 10 percent of the biomass is used as fuel to support the reaction, Kung says, adding that “90 percent is densified into a form that’s easier to handle and utilize.” He notes that the research received financial support from the Abdul Latif Jameel Water and Food Systems Lab and the Deshpande Center for Technological Innovation, both at MIT. Sonal Thengane, another postdoc in Ghoniem’s lab, participated in the effort to scale up the technology at the MIT Bates Lab (no relation to Richard Bates).

      The charcoal produced is more valuable per ton and easier to transport and sell than biomass, reducing transportation costs by two-thirds and giving farmers an additional income opportunity — and an incentive not to burn agricultural waste, Kung says. “There’s more income for farmers, and you get better air quality.”

      Roots in India

      When Kung became a Tata Fellow, he joined a program founded to take on the biggest challenges of the developing world, with a focus on India. According to Stoner, Tata Fellows, including Kung, typically visit India twice a year and spend six to eight weeks meeting stakeholders in industry, the government, and in communities to gain perspective on their areas of study.

      “A unique part of Tata is that you’re considering the ecosystem as a whole,” says Kung, who interviewed hundreds of smallholder farmers, met with truck drivers, and visited existing biomass processing plants during his Tata trips to India. (Along the way, he also connected with Indian engineer Vidyut Mohan, who became Takachar’s co-founder.)

      “It was very important for Kevin to be there walking about, experimenting, and interviewing farmers,” Stoner says. “He learned about the lives of farmers.”

      These experiences helped instill in Kung an appreciation for small farmers that still drives him today as Takachar rolls out its first pilot programs, tinkers with the technology, grows its team (now up to 10), and endeavors to build a revenue stream. So, while Takachar has gotten a lot of attention and accolades — from the IDEAS award to the Earthshot Prize — Kung says what motivates him is the prospect of improving people’s lives.

      The dream, he says, is to empower communities to help both the planet and themselves. “We’re excited about the environmental justice perspective,” he says. “Our work brings production and carbon removal or avoidance to rural communities — providing them with a way to convert waste, make money, and reduce air pollution.”

      This article appears in the Spring 2022 issue of Energy Futures, the magazine of the MIT Energy Initiative. More

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      Computing for the health of the planet

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      The health of the planet is one of the most important challenges facing humankind today. From climate change to unsafe levels of air and water pollution to coastal and agricultural land erosion, a number of serious challenges threaten human and ecosystem health.

      Ensuring the health and safety of our planet necessitates approaches that connect scientific, engineering, social, economic, and political aspects. New computational methods can play a critical role by providing data-driven models and solutions for cleaner air, usable water, resilient food, efficient transportation systems, better-preserved biodiversity, and sustainable sources of energy.

      The MIT Schwarzman College of Computing is committed to hiring multiple new faculty in computing for climate and the environment, as part of MIT’s plan to recruit 20 climate-focused faculty under its climate action plan. This year the college undertook searches with several departments in the schools of Engineering and Science for shared faculty in computing for health of the planet, one of the six strategic areas of inquiry identified in an MIT-wide planning process to help focus shared hiring efforts. The college also undertook searches for core computing faculty in the Department of Electrical Engineering and Computer Science (EECS).

      The searches are part of an ongoing effort by the MIT Schwarzman College of Computing to hire 50 new faculty — 25 shared with other academic departments and 25 in computer science and artificial intelligence and decision-making. The goal is to build capacity at MIT to help more deeply infuse computing and other disciplines in departments.

      Four interdisciplinary scholars were hired in these searches. They will join the MIT faculty in the coming year to engage in research and teaching that will advance physical understanding of low-carbon energy solutions, Earth-climate modeling, biodiversity monitoring and conservation, and agricultural management through high-performance computing, transformational numerical methods, and machine-learning techniques.

      “By coordinating hiring efforts with multiple departments and schools, we were able to attract a cohort of exceptional scholars in this area to MIT. Each of them is developing and using advanced computational methods and tools to help find solutions for a range of climate and environmental issues,” says Daniel Huttenlocher, dean of the MIT Schwarzman College of Computing and the Henry Warren Ellis Professor of Electrical Engineering and Computer Science. “They will also help strengthen cross-departmental ties in computing across an important, critical area for MIT and the world.”

      “These strategic hires in the area of computing for climate and the environment are an incredible opportunity for the college to deepen its academic offerings and create new opportunity for collaboration across MIT,” says Anantha P. Chandrakasan, dean of the MIT School of Engineering and the Vannevar Bush Professor of Electrical Engineering and Computer Science. “The college plays a pivotal role in MIT’s overarching effort to hire climate-focused faculty — introducing the critical role of computing to address the health of the planet through innovative research and curriculum.”

      The four new faculty members are:

      Sara Beery will join MIT as an assistant professor in the Faculty of Artificial Intelligence and Decision-Making in EECS in September 2023. Beery received her PhD in computing and mathematical sciences at Caltech in 2022, where she was advised by Pietro Perona. Her research focuses on building computer vision methods that enable global-scale environmental and biodiversity monitoring across data modalities, tackling real-world challenges including strong spatiotemporal correlations, imperfect data quality, fine-grained categories, and long-tailed distributions. She partners with nongovernmental organizations and government agencies to deploy her methods in the wild worldwide and works toward increasing the diversity and accessibility of academic research in artificial intelligence through interdisciplinary capacity building and education.

      Priya Donti will join MIT as an assistant professor in the faculties of Electrical Engineering and Artificial Intelligence and Decision-Making in EECS in academic year 2023-24. Donti recently finished her PhD in the Computer Science Department and the Department of Engineering and Public Policy at Carnegie Mellon University, co-advised by Zico Kolter and Inês Azevedo. Her work focuses on machine learning for forecasting, optimization, and control in high-renewables power grids. Specifically, her research explores methods to incorporate the physics and hard constraints associated with electric power systems into deep learning models. Donti is also co-founder and chair of Climate Change AI, a nonprofit initiative to catalyze impactful work at the intersection of climate change and machine learning that is currently running through the Cornell Tech Runway Startup Postdoc Program.

      Ericmoore Jossou will join MIT as an assistant professor in a shared position between the Department of Nuclear Science and Engineering and the faculty of electrical engineering in EECS in July 2023. He is currently an assistant scientist at the Brookhaven National Laboratory, a U.S. Department of Energy-affiliated lab that conducts research in nuclear and high energy physics, energy science and technology, environmental and bioscience, nanoscience, and national security. His research at MIT will focus on understanding the processing-structure-properties correlation of materials for nuclear energy applications through advanced experiments, multiscale simulations, and data science. Jossou obtained his PhD in mechanical engineering in 2019 from the University of Saskatchewan.

      Sherrie Wang will join MIT as an assistant professor in a shared position between the Department of Mechanical Engineering and the Institute for Data, Systems, and Society in academic year 2023-24. Wang is currently a Ciriacy-Wantrup Postdoctoral Fellow at the University of California at Berkeley, hosted by Solomon Hsiang and the Global Policy Lab. She develops machine learning for Earth observation data. Her primary application areas are improving agricultural management and forecasting climate phenomena. She obtained her PhD in computational and mathematical engineering from Stanford University in 2021, where she was advised by David Lobell. More

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      3Q: How MIT is working to reduce carbon emissions on our campus

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      Fast Forward: MIT’s Climate Action Plan for the Decade, launched in May 2021, charges MIT to eliminate its direct carbon emissions by 2050. Setting an interim goal of net zero emissions by 2026 is an important step to getting there. Joe Higgins, vice president for campus services and stewardship, speaks here about the coordinated, multi-team effort underway to address the Institute’s carbon-reduction goals, the challenges and opportunities in getting there, and creating a blueprint for a carbon-free campus in 2050.

      Q: The Fast Forward plan laid out specific goals for MIT to address its own carbon footprint. What has been the strategy to tackle these priorities?

      A: The launch of the Fast Forward Climate Action Plan empowered teams at MIT to expand the scope of our carbon reduction tasks beyond the work we’ve been doing to date. The on-campus activities called for in the plan range from substantially expanding our electric vehicle infrastructure on campus, to increasing our rooftop solar installations, to setting impact goals for food, water, and waste systems. Another strategy utilizes artificial intelligence to further reduce energy consumption and emissions from our buildings. When fully implemented, these systems will adjust a building’s temperature setpoints throughout the day while maintaining occupant comfort, and will use occupancy data, weather forecasts, and carbon intensity projections from the grid to make more efficient use of energy. 

      We have tremendous momentum right now thanks to the progress made over the past decade by our teams — which include planners, designers, engineers, construction managers, and sustainability and operations experts. Since 2014, our efforts to advance energy efficiency and incorporate renewable energy have reduced net emissions on campus by 20% (from a 2014 baseline) despite significant campus growth. One of our current goals is to further reduce energy use in high-intensity research buildings — 20 of our campus buildings consume more than 50% of our energy. To reduce energy usage in these buildings we have major energy retrofit projects in design or in planning for buildings 32, 46, 68, 76, E14, and E25, and we expect this work will reduce overall MIT emissions by an additional 10 to 15%.

      Q: The Fast Forward plan acknowledges the challenges we face in our efforts to reach our campus emission reduction goals, in part due to the current state of New England’s electrical grid. How does MIT’s district energy system factor into our approach? 

      A: MIT’s district energy system is a network of underground pipes and power lines that moves energy from the Central Utilities Plant (CUP) around to the vast majority of Institute buildings to provide electricity, heating, and air conditioning. Using a closed-loop, central-source system like this enables MIT to operate more efficiently by using less energy to heat and cool its buildings and labs, and by maintaining better load control to accommodate seasonal variations in peak demand.

      When the new MIT campus was built in Cambridge in 1916, it included a centralized state-of-the-art steam and electrical power plant that would service the campus buildings. This central district energy approach allowed MIT to avoid having individual furnaces in each building and to easily incorporate progressively cleaner fuel sources campus-wide over the years. After starting with coal as a primary energy source, MIT transitioned to fuel oil, then to natural gas, and then to cogeneration in 1995 — and each step has made the campus more energy efficient. Our continuous investment in a centralized infrastructure has facilitated our ability to improve energy efficiency while adding capacity; as new technologies become available, we can implement them across the entire campus. Our district energy system is very adaptable to seasonal variations in demand for cooling, heating and electricity, and builds upon decades of centralized investments in energy-efficient infrastructure.

      This past year, MIT completed a major upgrade of the district energy system whereby the majority of buildings on campus now benefit from the most advanced cogeneration technology for combined heating, cooling, and power delivery. This system generates electrical power that produces 15 to 25% less carbon than the current New England grid. We also have the ability to export power during times when the grid is most stressed, which contributes to the resiliency of local energy systems. On the flip side, any time the grid is a cleaner option, MIT is able to import a higher amount of electricity from the utility by distributing this energy through our centralized system. In fact, it’s important to note that we have the ability to import 100% of our electrical energy from the grid as it becomes cleaner. We anticipate that this will happen as the next major wave of technology innovation unfolds and the abundance of offshore wind and other renewable resources increases as anticipated by the end of this decade. As the grid gets greener, our adaptable district energy system will bring us closer to meeting our decarbonization goals.

      MIT’s ability to adapt its system and use new technologies is crucial right now as we work in collaboration with faculty, students, industry experts, peer institutions, and the cities of Cambridge and Boston to evaluate various strategies, opportunities, and constraints. In terms of evolving into a next-generation district energy system, we are reviewing options such as electric steam boilers and industrial-scale heat pumps, thermal batteries, geothermal exchange, micro-reactors, bio-based fuels, and green hydrogen produced from renewable energy. We are preparing to incorporate the most beneficial technologies into a blueprint that will get us to our 2050 goal.

      Q: What is MIT doing in the near term to reach the carbon-reduction goals of the climate action plan?

      A: In the near term, we are exploring several options, including enabling large-scale renewable energy projects and investing in verified carbon offset projects that reduce, avoid, or sequester carbon. In 2016, MIT joined a power purchase agreement (PPA) partnership that enabled the construction of a 650-acre solar farm in North Carolina and resulted in the early retirement of a nearby coal plant. We’ve documented a huge emissions savings from this, and we’re exploring how to do something similar on a much larger scale with a broader group of partners. As we seek out collaborative opportunities that enable the development of new renewable energy sources, we hope to provide a model for other institutions and organizations, as the original PPA did. Because PPAs accelerate the de-carbonization of regional electricity grids, they can have an enormous and far-reaching impact. We see these partnerships as an important component of achieving net zero emissions on campus as well as accelerating the de-carbonization of regional power grids — a transformation that must take place to reach zero emissions by 2050.

      Other near-term initiatives include enabling community solar power projects in Massachusetts to support the state’s renewable energy goals and provide opportunities for more property owners (municipalities, businesses, homeowners, etc.) to purchase affordable renewable energy. MIT is engaged with three of these projects; one of them is in operation today in Middleton, and the two others are scheduled to be built soon on Cape Cod.

      We’re joining the commonwealth and its cities, its organizations and utility providers on an unprecedented journey — the global transition to a clean energy system. Along the way, everything is going to change as technologies and the grid continue to evolve. Our focus is on both the near term and the future, as we plan a path into the next energy era. More

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      in Security

      J-WAFS awards $150K Solutions grant to Patrick Doyle and team for rapid removal of micropollutants from water

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      The Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) has awarded a 2022 J-WAFS Solutions grant to Patrick S. Doyle, the Robert T. Haslam Professor of Chemical Engineering at MIT, for his innovative system to tackle water pollution. Doyle will be working with co-Principal Investigator Rafael Gomez-Bombarelli, assistant professor in materials processing in the Department of Materials Science, as well as PhD students Devashish Gokhale and Tynan Perez. Building off of findings from a 2019 J-WAFS seed grant, Doyle and the research team will create cost-effective industry-scale processes to remove micropollutants from water. Project work will commence this month.

      The J-WAFS Solutions program provides one-year, renewable, commercialization grants to help move MIT technology from the laboratory to market. Grants of up to $150,000 are awarded to researchers with breakthrough technologies and inventions in water or food. Since its launch in 2015, J-WAFS Solutions grants have led to seven spinout companies and helped commercialize two products as open-source technologies. The grant program is supported by Community Jameel.

      A widespread problem 

      Micropollutants are contaminants that occur in low concentrations in the environment, yet continuous exposure and bioaccumulation of micropollutants make them a cause for concern. According to the U.S. Environmental Protection Agency, the plastics derivative Bisphenol A (BPA), the “forever chemicals” per-and polyfluoroalkyl substances (PFAS), and heavy metals like lead are common micropollutants known to be found in more than 85 percent of rivers, ponds, and lakes in the United States. Many of these bodies of water are sources of drinking water. Over long periods of time, exposure to micropollutants through drinking water can cause physiological damage in humans, increasing the risk of cancer, developmental disorders, and reproductive failure.

      Since micropollutants occur in low concentrations, it is difficult to detect and monitor their presence, and the chemical diversity of micropollutants makes it difficult to inexpensively remove them from water. Currently, activated carbon is the industry standard for micropollutant elimination, but this method cannot efficiently remove contaminants at parts-per-billion and parts-per-trillion concentrations. There are also strong sustainability concerns associated with activated carbon production, which is energy-intensive and releases large volumes of carbon dioxide.

      A solution with societal and economic benefits

      Doyle and his team are developing a technology that uses sustainable hydrogel microparticles to remove micropollutants from water. The polymeric hydrogel microparticles use chemically anchored structures including micelles and other chelating agents that act like a sponge by absorbing organic micropollutants and heavy metal ions. The microparticles are large enough to separate from water using simple gravitational settling. The system is sustainable because the microparticles can be recycled for continuous use. In testing, the long-lasting, reusable microparticles show quicker removal of contaminants than commercial activated carbon. The researchers plan to utilize machine learning to find optimal microparticle compositions that maximize performance on complex combinations of micropollutants in simulated and real wastewater samples.

      Economically, the technology is a new offering that has applications in numerous large markets where micropollutant elimination is vital, including municipal and industrial water treatment equipment, as well as household water purification systems. The J-WAFS Solutions grant will allow the team to build and test prototypes of the water treatment system, identify the best use cases and customers, and perform technoeconomic analyses and market research to formulate a preliminary business plan. With J-WAFS commercialization support, the project could eventually lead to a startup company.

      “Emerging micropollutants are a growing threat to drinking water supplies worldwide,” says J-WAFS Director John H. Lienhard, the Abdul Latif Jameel Professor of Water at MIT. “Cost-effective and scalable technologies for micropollutant removal are urgently needed. This project will develop and commercialize a promising new tool for water treatment, with the goal of improving water quality for millions of people.” More

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      in Environment

      Silk offers an alternative to some microplastics

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      Microplastics, tiny particles of plastic that are now found worldwide in the air, water, and soil, are increasingly recognized as a serious pollution threat, and have been found in the bloodstream of animals and people around the world.

      Some of these microplastics are intentionally added to a variety of products, including agricultural chemicals, paints, cosmetics, and detergents — amounting to an estimated 50,000 tons a year in the European Union alone, according to the European Chemicals Agency. The EU has already declared that these added, nonbiodegradable microplastics must be eliminated by 2025, so the search is on for suitable replacements, which do not currently exist.

      Now, a team of scientists at MIT and elsewhere has developed a system based on silk that could provide an inexpensive and easily manufactured substitute. The new process is described in a paper in the journal Small, written by MIT postdoc Muchun Liu, MIT professor of civil and environmental engineering Benedetto Marelli, and five others at the chemical company BASF in Germany and the U.S.

      The microplastics widely used in industrial products generally protect some specific active ingredient (or ingredients) from being degraded by exposure to air or moisture, until the time they are needed. They provide a slow release of the active ingredient for a targeted period of time and minimize adverse effects to its surroundings. For example, vitamins are often delivered in the form of microcapsules packed into a pill or capsule, and pesticides and herbicides are similarly enveloped. But the materials used today for such microencapsulation are plastics that persist in the environment for a long time. Until now, there has been no practical, economical substitute available that would biodegrade naturally.

      Much of the burden of environmental microplastics comes from other sources, such as the degradation over time of larger plastic objects such as bottles and packaging, and from the wear of car tires. Each of these sources may require its own kind of solutions for reducing its spread, Marelli says. The European Chemical Agency has estimated that the intentionally added microplastics represent approximately 10-15 percent of the total amount in the environment, but this source may be relatively easy to address using this nature-based biodegradable replacement, he says.

      “We cannot solve the whole microplastics problem with one solution that fits them all,” he says. “Ten percent of a big number is still a big number. … We’ll solve climate change and pollution of the world one percent at a time.”

      Unlike the high-quality silk threads used for fine fabrics, the silk protein used in the new alternative material is widely available and less expensive, Liu says. While silkworm cocoons must be painstakingly unwound to produce the fine threads needed for fabric, for this use, non-textile-quality cocoons can be used, and the silk fibers can simply be dissolved using a scalable water-based process. The processing is so simple and tunable that the resulting material can be adapted to work on existing manufacturing equipment, potentially providing a simple “drop in” solution using existing factories.

      Silk is recognized as safe for food or medical use, as it is nontoxic and degrades naturally in the body. In lab tests, the researchers demonstrated that the silk-based coating material could be used in existing, standard spray-based manufacturing equipment to make a standard water-soluble microencapsulated herbicide product, which was then tested in a greenhouse on a corn crop. The test showed it worked even better than an existing commercial product, inflicting less damage to the plants, Liu says.

      While other groups have proposed degradable encapsulation materials that may work at a small laboratory scale, Marelli says, “there is a strong need to achieve encapsulation of high-content actives to open the door to commercial use. The only way to have an impact is where we can not only replace a synthetic polymer with a biodegradable counterpart, but also achieve performance that is the same, if not better.”

      The secret to making the material compatible with existing equipment, Liu explains, is in the tunability of the silk material. By precisely adjusting the polymer chain arrangements of silk materials and addition of a surfactant, it is possible to fine-tune the properties of the resulting coatings once they dry out and harden. The material can be hydrophobic (water-repelling) even though it is made and processed in a water solution, or it can be hydrophilic (water-attracting), or anywhere in between, and for a given application it can be made to match the characteristics of the material it is being used to replace.

      In order to arrive at a practical solution, Liu had to develop a way of freezing the forming droplets of encapsulated materials as they were forming, to study the formation process in detail. She did this using a special spray-freezing system, and was able to observe exactly how the encapsulation works in order to control it better. Some of the encapsulated “payload” materials, whether they be pesticides or nutrients or enzymes, are water-soluble and some are not, and they interact in different ways with the coating material.

      “To encapsulate different materials, we have to study how the polymer chains interact and whether they are compatible with different active materials in suspension,” she says. The payload material and the coating material are mixed together in a solution and then sprayed. As droplets form, the payload tends to be embedded in a shell of the coating material, whether that’s the original synthetic plastic or the new silk material.

      The new method can make use of low-grade silk that is unusable for fabrics, and large quantities of which are currently discarded because they have no significant uses, Liu says. It can also use used, discarded silk fabric, diverting that material from being disposed of in landfills.

      Currently, 90 percent of the world’s silk production takes place in China, Marelli says, but that’s largely because China has perfected the production of the high-quality silk threads needed for fabrics. But because this process uses bulk silk and has no need for that level of quality, production could easily be ramped up in other parts of the world to meet local demand if this process becomes widely used, he says.

      “This elegant and clever study describes a sustainable and biodegradable silk-based replacement for microplastic encapsulants, which are a pressing environmental challenge,” says Alon Gorodetsky, an associate professor of chemical and biomolecular engineering at the University of California at Irvine, who was not associated with this research. “The modularity of the described materials and the scalability of the manufacturing processes are key advantages that portend well for translation to real-world applications.”

      This process “represents a potentially highly significant advance in active ingredient delivery for a range of industries, particularly agriculture,” says Jason White, director of the Connecticut Agricultural Experiment Station, who also was not associated with this work. “Given the current and future challenges related to food insecurity, agricultural production, and a changing climate, novel strategies such as this are greatly needed.”

      The research team also included Pierre-Eric Millard, Ophelie Zeyons, Henning Urch, Douglas Findley and Rupert Konradi from the BASF corporation, in Germany and in the U.S. The work was supported by BASF through the Northeast Research Alliance (NORA). More

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      in Environment

      Four researchers with MIT ties earn Schmidt Science Fellowships

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      Four researchers with MIT ties — Juncal Arbelaiz, Xiangkun (Elvis) Cao, Sandya Subramanian, and Heather Zlotnick ’17 — have been honored with competitive Schmidt Science Fellowships.

      Created in 2017, the fellows program aims to bring together the world’s brightest minds “to solve society’s toughest challenges.”

      The four MIT-affiliated researchers are among 29 Schmidt Science Fellows from around the world who will receive postdoctoral support for either one or two years with an annual stipend of $100,000, along with individualized mentoring and participation in the program’s Global Meeting Series. The fellows will also have opportunities to engage with thought-leaders from science, business, policy, and society. According to the award announcement, the fellows are expected to pursue research that shifts from the focus of their PhDs, to help expand and enhance their futures as scientific leaders.

      Juncal Arbelaiz is a PhD candidate in applied mathematics at MIT, who is completing her doctorate this summer. Her doctoral research at MIT is advised by Ali Jadbabaie, the JR East Professor of Engineering and head of the Department of Civil and Environmental Engineering; Anette Hosoi, the Neil and Jane Pappalardo Professor of Mechanical Engineering and associate dean of the School of Engineering; and Bassam Bamieh, professor of mechanical engineering and associate director of the Center for Control, Dynamical Systems, and Computation at the University of California at Santa Barbara. Arbelaiz’s research revolves around the design of optimal decentralized intelligence for spatially-distributed dynamical systems.

      “I cannot think of a better way to start my independent scientific career. I feel very excited and grateful for this opportunity,” says Arbelaiz. With her fellowship, she will enlist systems biology to explore how the nervous system encodes and processes sensory information to address future safety-critical artificial intelligence applications. “The Schmidt Science Fellowship will provide me with a unique opportunity to work at the intersection of biological and machine intelligence for two years and will be a steppingstone towards my longer-term objective of becoming a researcher in bio-inspired machine intelligence,” she says.

      Xiangkun (Elvis) Cao is currently a postdoc in the lab of T. Alan Hatton, the Ralph Landau Professor in Chemical Engineering, and an Impact Fellow at the MIT Climate and Sustainability Consortium. Cao received his PhD in mechanical engineering from Cornell University in 2021, during which he focused on microscopic precision in the simultaneous delivery of light and fluids by optofluidics, with advances relevant to health and sustainability applications. As a Schmidt Science Fellow, he plans to be co-advised by Hatton on carbon capture, and Ted Sargent, professor of chemistry at Northwestern University, on carbon utilization. Cao is passionate about integrated carbon capture and utilization (CCU) from molecular to process levels, machine learning to inspire smart CCU, and the nexus of technology, business, and policy for CCU.

      “The Schmidt Science Fellowship provides the perfect opportunity for me to work across disciplines to study integrated carbon capture and utilization from molecular to process levels,” Cao explains. “My vision is that by integrating carbon capture and utilization, we can concurrently make scientific discoveries and unlock economic opportunities while mitigating global climate change. This way, we can turn our carbon liability into an asset.”

      Sandya Subramanian, a 2021 PhD graduate of the Harvard-MIT Program in Health Sciences and Technology (HST) in the area of medical engineering and medical physics, is currently a postdoc at Stanford Data Science. She is focused on the topics of biomedical engineering, statistics, machine learning, neuroscience, and health care. Her research is on developing new technologies and methods to study the interactions between the brain, the autonomic nervous system, and the gut. “I’m extremely honored to receive the Schmidt Science Fellowship and to join the Schmidt community of leaders and scholars,” says Subramanian. “I’ve heard so much about the fellowship and the fact that it can open doors and give people confidence to pursue challenging or unique paths.”

      According to Subramanian, the autonomic nervous system and its interactions with other body systems are poorly understood but thought to be involved in several disorders, such as functional gastrointestinal disorders, Parkinson’s disease, diabetes, migraines, and eating disorders. The goal of her research is to improve our ability to monitor and quantify these physiologic processes. “I’m really interested in understanding how we can use physiological monitoring technologies to inform clinical decision-making, especially around the autonomic nervous system, and I look forward to continuing the work that I’ve recently started at Stanford as Schmidt Science Fellow,” she says. “A huge thank you to all of the mentors, colleagues, friends, and leaders I had the pleasure of meeting and working with at HST and MIT; I couldn’t have done this without everything I learned there.”

      Hannah Zlotnick ’17 attended MIT for her undergraduate studies, majoring in biological engineering with a minor in mechanical engineering. At MIT, Zlotnick was a student-athlete on the women’s varsity soccer team, a UROP student in Alan Grodzinsky’s laboratory, and a member of Pi Beta Phi. For her PhD, Zlotnick attended the University of Pennsylvania, and worked in Robert Mauck’s laboratory within the departments of Bioengineering and Orthopaedic Surgery.

      Zlotnick’s PhD research focused on harnessing remote forces, such as magnetism or gravity, to enhance engineered cartilage and osteochondral repair both in vitro and in large animal models. Zlotnick now plans to pivot to the field of biofabrication to create tissue models of the knee joint to assess potential therapeutics for osteoarthritis. “I am humbled to be a part of the Schmidt Science Fellows community, and excited to venture into the field of biofabrication,” Zlotnick says. “Hopefully this work uncovers new therapies for patients with inflammatory joint diseases.” More

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      in Energy

      Getting the carbon out of India’s heavy industries

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      The world’s third largest carbon emitter after China and the United States, India ranks seventh in a major climate risk index. Unless India, along with the nearly 200 other signatory nations of the Paris Agreement, takes aggressive action to keep global warming well below 2 degrees Celsius relative to preindustrial levels, physical and financial losses from floods, droughts, and cyclones could become more severe than they are today. So, too, could health impacts associated with the hazardous air pollution levels now affecting more than 90 percent of its population.  

      To address both climate and air pollution risks and meet its population’s escalating demand for energy, India will need to dramatically decarbonize its energy system in the coming decades. To that end, its initial Paris Agreement climate policy pledge calls for a reduction in carbon dioxide intensity of GDP by 33-35 percent by 2030 from 2005 levels, and an increase in non-fossil-fuel-based power to about 40 percent of cumulative installed capacity in 2030. At the COP26 international climate change conference, India announced more aggressive targets, including the goal of achieving net-zero emissions by 2070.

      Meeting its climate targets will require emissions reductions in every economic sector, including those where emissions are particularly difficult to abate. In such sectors, which involve energy-intensive industrial processes (production of iron and steel; nonferrous metals such as copper, aluminum, and zinc; cement; and chemicals), decarbonization options are limited and more expensive than in other sectors. Whereas replacing coal and natural gas with solar and wind could lower carbon dioxide emissions in electric power generation and transportation, no easy substitutes can be deployed in many heavy industrial processes that release CO2 into the air as a byproduct.

      However, other methods could be used to lower the emissions associated with these processes, which draw upon roughly 50 percent of India’s natural gas, 25 percent of its coal, and 20 percent of its oil. Evaluating the potential effectiveness of such methods in the next 30 years, a new study in the journal Energy Economics led by researchers at the MIT Joint Program on the Science and Policy of Global Change is the first to explicitly explore emissions-reduction pathways for India’s hard-to-abate sectors.

      Using an enhanced version of the MIT Economic Projection and Policy Analysis (EPPA) model, the study assesses existing emissions levels in these sectors and projects how much they can be reduced by 2030 and 2050 under different policy scenarios. Aimed at decarbonizing industrial processes, the scenarios include the use of subsidies to increase electricity use, incentives to replace coal with natural gas, measures to improve industrial resource efficiency, policies to put a price on carbon, carbon capture and storage (CCS) technology, and hydrogen in steel production.

      The researchers find that India’s 2030 Paris Agreement pledge may still drive up fossil fuel use and associated greenhouse gas emissions, with projected carbon dioxide emissions from hard-to-abate sectors rising by about 2.6 times from 2020 to 2050. But scenarios that also promote electrification, natural gas support, and resource efficiency in hard-to-abate sectors can lower their CO2 emissions by 15-20 percent.

      While appearing to move the needle in the right direction, those reductions are ultimately canceled out by increased demand for the products that emerge from these sectors. So what’s the best path forward?

      The researchers conclude that only the incentive of carbon pricing or the advance of disruptive technology can move hard-to-abate sector emissions below their current levels. To achieve significant emissions reductions, they maintain, the price of carbon must be high enough to make CCS economically viable. In that case, reductions of 80 percent below current levels could be achieved by 2050.

      “Absent major support from the government, India will be unable to reduce carbon emissions in its hard-to-abate sectors in alignment with its climate targets,” says MIT Joint Program deputy director Sergey Paltsev, the study’s lead author. “A comprehensive government policy could provide robust incentives for the private sector in India and generate favorable conditions for foreign investments and technology advances. We encourage decision-makers to use our findings to design efficient pathways to reduce emissions in those sectors, and thereby help lower India’s climate and air pollution-related health risks.” More