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    MIT scholars will take commercial break with entrepreneurial scholarship

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    Two MIT scholars, each with a strong entrepreneurial drive, have received 2024 Kavanaugh Fellowship awards, advancing their quest to turn pioneering research into profitable commercial enterprises.The Kavanaugh Translational Fellows Program gives scholars training to lead organizations that will bring their research to market. PhD candidates Grant Knappe and Arjav Shah are this year’s recipients. Knappe is developing a drug delivery platform for an emerging class of medicines called nucleic acid therapeutics. Shah is using hydrogel microparticles to clean up water polluted by heavy metals and other contaminants.Knappe and Shah will begin their fellowship with years of entrepreneurial expertise under their belts. They’ve developed and refined their business plans through MIT’s innovation ecosystem, including the Sandbox, the Legatum Center, the Venture Mentoring Service, the National Science Foundation’s I-Corps Program, and Blueprint by The Engine. Now, the yearlong Kavanaugh Fellowship will give the scholars time to focus exclusively on testing their business plans and exercising decision-making skills — critical to startup success — with the guidance of MIT mentors.“It’s a testament to the support and direction they’ve received from the MIT community that their entrepreneurial aspirations have evolved and matured over time,” says Michael J. Cima, program director for the Kavanaugh program and the David H. Koch Professor of Engineering in the Department of Materials Science and Engineering.Founded in 2016, the Kavanaugh program was instrumental in helping past fellows launch several robust startups, including low-carbon cement manufacturer Sublime Systems and SiTration, which is using a new type of filtration membrane to extract critical materials such as lithium.A safer way to deliver breakthrough medicinesNucleic acid therapeutics, including mRNA and CRISPR, are disrupting today’s clinical landscape thanks to their promise of targeting disease treatment according to genetic blueprints. But the first methods of delivering these molecules to the body used viruses as their transport, raising patient safety concerns.“Humans have figured out how to engineer certain viruses found in nature to deliver specific cargoes [for disease treatment],” says Knappe. “But because they look like viruses, the human immune system sees them as a danger signal and creates an immune reaction that can be harmful to patients.”Given the safety profile issues of viral delivery, researchers turned to non-viral technologies that use lipid nanoparticle technology, a mixture of different lipid-like materials, assembled into particles to protect the mRNA therapeutic from getting degraded before it reaches a cell of interest. “Because they don’t look like viruses there, the immune system generally tolerates them,” adds Knappe.Recent data show lipid nanoparticles can now target the lung, opening the potential for novel treatments of deadly cancers and other diseases.Knappe’s work in MIT’s Bathe BioNanoLab focused on building such a non-viral delivery platform based on a different technology: nucleic acid nanoparticles, which combine the attractive components of both viral and non-viral systems. Knappe will spend his Kavanaugh Fellowship year developing proof-of-concept data for his drug delivery method and building the team and funding needed to commercialize the technology.A PhD candidate in the Department of Chemical Engineering (ChemE), Knappe was initially attracted to MIT because of its intellectual openness. “You can work with any faculty member in other departments. I wasn’t restricted to the chemical engineering faculty,” says Knappe, whose supervisor, Professor Mark Bathe, is in the Department of Biological Engineering.Knappe, who is from New Jersey, welcomes the challenges that will come in his Kavanaugh year, including the need to pinpoint the right story that will convince venture capitalists and other funders to bet on his technology. Attracting talent is also top of mind. “How do you convince really talented people that have a lot of opportunities to work on what you work on? Building the first team is going to be critical,” he says. The network Knappe has been building in his years at MIT is paying dividends now.Targeting “forever chemicals” in waterThat network includes Shah. The two fellows met when they worked on the MIT Science Policy Review, a student-run journal concerned with the intersection of science, technology, and policy. Knappe and Shah did not compete directly academically but used their biweekly coffee walks as a welcome sounding board. Naturally, they were pleased when they found out they had both been chosen for the Kavanaugh Fellowship. So far, they have been too busy to celebrate over a beer.“We are good collaborators with research, as well,” says Shah. “Now we’re going on this entrepreneurial journey together. It’s been exciting.”Shah is a PhD candidate in ChemE’s Chemical Engineering Practice program. He got interested in the global imperative for cleaner water at a young age. His hometown of Surat is the heart of India’s textile industry. “Growing up, it wasn’t hard to see the dye-colored water flowing into your rivers and streams,” Shah says. “Playing a role in fostering positive change in water treatment fills me with a profound sense of purpose.”Shah’s work, broadly, is to clean toxic chemicals called micropollutants from water in an efficient and sustainable manner. “It’s humanly impossible to turn a blind eye to our water problems,” he says, which can be categorized as accessibility, availability, and quality. Water problems are global and complex, not just because of the technological challenges but also sociopolitical ones, he adds.Manufactured chemicals called per- and polyfluoroalkyl substances (PFAS), or “forever chemicals,” are in the news these days. PFAS, which go into making nonstick cookware and waterproof clothing, are just one of more than 10,000 such emerging contaminants that have leached into water streams. “These are extremely difficult to remove using existing systems because of their chemical diversity and low concentrations,” Shah says. “The concentrations are akin to dropping an aspirin tablet in an Olympic-sized swimming pool.” But no less toxic for that.In the lab at MIT, Shah is working with Devashish Gokhale, a fellow PhD student, and Patrick S. Doyle, the Robert T. Haslam (1911) Professor of Chemical Engineering, to commercialize an innovative microparticle technology, hydroGel, to remove these micropollutants in an effective, facile, and sustainable manner. Hydrogels are a broad class of polymer materials that can hold large quantities of water.“Our materials are like Boba beads. We are trying to save the world with our Boba beads,” says Shah with a laugh. “And we have functionalized these particles with tunable chemistries to target different micropollutants in a single unit operation.”Due to its outsized environmental impact, industrial water is the first application Shah is targeting. Today, wastewater treatment emits more than 3 percent of global carbon dioxide emissions, which is more than the shipping industry’s emissions, for example. The current state of the art for removing micropollutants in the industry is to use activated carbon filters. “[This technology] comes from coal, so it’s unsustainable,” Shah says. And the activated carbon filters are hard to reuse. “Our particles are reusable, theoretically infinitely.”“I’m very excited to be able to take advantage of the mentorship we have from the Kavanaugh team to take this technology to its next inflection point, so that we are ready to go out in the market and start making a huge impact,” he says.A dream communityShah and Knappe have become adept at navigating the array of support and mentorship opportunities MIT has to offer. Shah worked with a small team of seasoned professionals in the water space from the MIT Venture Mentoring Service. “They’ve helped us every step of the way as we think about commercializing the technology,” he says.Shah worked with MIT Sandbox, which provides a seed grant to help find the right product-market fit. He is also a fellow with the Legatum Center for Development and Entrepreneurship, which focuses on entrepreneurship in emerging countries in growth markets.“We’re exploring the potential for this technology and its application in a lot of different markets, including India. Because that’s close to my heart,” Shah says. “The Legatum community has been unique, where you can have those extremely hard conversations, confront yourself with those fears, and then talk it out with the group of fellows.”The Abdul Latif Jameel Water and Food Systems Lab, or J-WAFS, has been an integral part of Shah’s journey with research and commercialization support through its Solutions Grant and a travel award to the Stockholm World Water Week in August 2023.Knappe has also taken advantage of many innovation programs, including MIT’s Blueprint by the Engine, which helps researchers explore commercial opportunities of their work, plus programs outside of MIT but with strong on-campus ties such as Nucleate Activator and Frequency Bio.It was during one of these programs that he was inspired by two postdocs working in Bathe’s lab and spinning out biotech startups from their research, Floris Engelhardt and James Banal. Engelhardt helped spearhead Kano Therapeutics, and Banal launched Cache DNA.“I was passively absorbing and watching everything that they were going through and what they were excited about and challenged with. I still talk to them pretty regularly to this day,” Knappe says. “It’s been really great to have them as continual mentors, throughout my PhD and as I transition out of the lab.”Shah says he is grateful not only for being selected for the Kavanaugh Fellowship but to MIT as a community. “MIT has been more than a dream come true,” he says. He will have the opportunity to explore a different side of the institution as he enters the MBA program at MIT Sloan School of Management this fall. Shah expects this program, along with his Kavanaugh training, will supply the skills he needs to scale the business so it can make a difference in the world.“I always keep coming back to the question ‘How does what I do matter to the person on the street?’ This guides me to look at the bigger picture, to contextualize my research to solving important problems,” Shah says. “So many great technologies are being worked on each day, but only a minuscule fraction make it to the market.”Knappe is equally dedicated to serving a larger purpose. “With the right infrastructure, between basic fundamental science, conducted in academia, funded by government, and then translated by companies, we can make products that could improve everyone’s life across the world,” he says.Past Kavanaugh Fellows are credited with spearheading commercial outfits that have indeed made a difference. This year’s fellows are poised to follow their lead. But first they will have that beer together to celebrate. More

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      A new way to swiftly eliminate micropollutants from water

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      “Zwitterionic” might not be a word you come across every day, but for Professor Patrick Doyle of the MIT Department of Chemical Engineering, it’s a word that’s central to the technology his group is developing to remove micropollutants from water. Derived from the German word “zwitter,” meaning “hybrid,” “zwitterionic” molecules are those with an equal number of positive and negative charges.

      Devashish Gokhale, a PhD student in Doyle’s lab, uses the example of a magnet to describe zwitterionic materials. “On a magnet, you have a north pole and a south pole that stick to each other, and on a zwitterionic molecule, you have a positive charge and a negative charge which stick to each other in a similar way.” Because many inorganic micropollutants and some organic micropollutants are themselves charged, Doyle and his team have been investigating how to deploy zwitterionic molecules to capture micropollutants in water. 

      In a new paper in Nature Water, Doyle, Gokhale, and undergraduate student Andre Hamelberg explain how they use zwitterionic hydrogels to sustainably capture both organic and inorganic micropollutants from water with minimal operational complexity. In the past, zwitterionic molecules have been used as coatings on membranes for water treatment because of their non-fouling properties. But in the Doyle group’s system, zwitterionic molecules are used to form the scaffold material, or backbone within the hydrogel — a porous three-dimensional network of polymer chains that contains a significant amount of water. “Zwitterionic molecules have very strong attraction to water compared to other materials which are used to make hydrogels or polymers,” says Gokhale. What’s more, the positive and negative charges on zwitterionic molecules cause the hydrogels to have lower compressibility than what has been commonly observed in hydrogels. This makes for significantly more swollen, robust, and porous hydrogels, which is important for the scale up of the hydrogel-based system for water treatment.

      The early stages of this research were supported by a seed grant from MIT’s Abdul Latif Jameel Water and Food Systems Lab (J-WAFS). Doyle’s group is now pursuing commercialization of the platform for both at-home use and industrial scale applications, with support from a J-WAFS Solutions grant.

      Seeking a sustainable solution

      Micropollutants are chemically diverse materials that can be harmful to human health and the environment, even though they are typically found at low concentrations (micrograms to milligrams per liter) relative to conventional contaminants. Micropollutants can be organic or inorganic and can be naturally-occurring or synthetic. Organic micropollutants are mostly carbon-based molecules and include pesticides and per- and polyfluoroalkyl substances (PFAS), known as “forever chemicals.” Inorganic micropollutants, such as heavy metals like lead and arsenic, tend to be smaller than organic micropollutants. Unfortunately, both organic and inorganic micropollutants are pervasive in the environment.

      Many micropollutants come from industrial processes, but the effects of human-induced climate change are also contributing to the environmental spread of micropollutants. Gokhale explains that, in California, for example, fires burn plastic electrical cables and leech micropollutants into natural ecosystems. Doyle adds that “outside of climate change, things like pandemics can spike the number of organic micropollutants in the environment due to high concentrations of pharmaceuticals in wastewater.”

      It’s no surprise then, that over the past few years micropollutants have become more and more of a concern. These chemicals have garnered attention in the media and led to “significant change in the environmental engineering and regulatory landscape” says Gokhale. In March 2023, the U.S. Environmental Protection Agency (EPA) proposed a strict, federal standard that would regulate six different PFAS chemicals in drinking water. Just last October, the EPA proposed banning the micropollutant trichloroethylene, a cancer-causing chemical that can be found in brake cleaners and other consumer products. And as recently as November, the EPA proposed that water utilities nationwide be required to replace all of their lead pipes to protect the public from lead exposure. Internationally, Gokhale notes the Oslo Paris Convention, whose mission is to protect the marine environment of the northeast Atlantic Ocean, including phasing out the discharge of offshore chemicals from the oil and gas industries. 

      With each new, necessary regulation to protect the safety of our water resources, the need for effective water treatment processes grows. Compounding this challenge is the need to make water treatment processes that are sustainable and energy-efficient. 

      The benchmark method to treat micropollutants in water is activated carbon. However, making filters with activated carbon is energy-intensive, requiring very high temperatures in large, centralized facilities. Gokhale says approximately “four kilograms of coal are needed to make one kilogram of activated carbon, so you lose a significant amount of carbon dioxide to the environment.” According to the World Economic Forum, global water and wastewater treatment accounts for 5 percent of annual emissions. In the U.S. alone, the EPA reports that drinking water and wastewater systems account for over 45 million tons of greenhouse gas emissions annually.

      “We need to develop methods which have smaller climate footprints than methods which are being used industrially today,” says Gokhale.

      Supporting a “high-risk” project

      In September 2019, Doyle and his lab embarked on an initial project to develop a microparticle-based platform to remove a broad range of micropollutants from water. Doyle’s group had been using hydrogels in pharmaceutical processing to formulate drug molecules into pill format. When he learned about the J-WAFS seed grant opportunity for early-stage research in water and food systems, Doyle realized his pharmaceutical work with hydrogels could be applied to environmental issues like water treatment. “I would never have gotten funding for this project if I went to the NSF [National Science Foundation], because they would just say, ‘you’re not a water person.’ But the J-WAFS seed grant offered a way for a high-risk, high-reward kind of project,” Doyle says.

      In March 2022, Doyle, Gokhale, and MIT undergraduate Ian Chen published findings from the seed grant work, describing their use of micelles within hydrogels for water treatment. Micelles are spherical structures that form when molecules called surfactants (found in things like soap), come in contact with water or other liquids. The team was able to synthesize micelle-laden hydrogel particles that soak up micropollutants from water like a sponge. Unlike activated carbon, the hydrogel particle system is made from environmentally friendly materials. Furthermore, the system’s materials are made at room temperature, making them exceedingly more sustainable than activated carbon.

      Building off the success of the seed grant, Doyle and his team were awarded a J-WAFS Solutions grant in September 2022 to help move their technology from the lab to the market. With this support, the researchers have been able to build, test, and refine pilot-scale prototypes of their hydrogel platform. System iterations during the solutions grant period have included the use of the zwitterionic molecules, a novel advancement from the seed grant work.  

      Rapid elimination of micropollutants is of special importance in commercial water treatment processes, where there is a limited amount of time water can spend inside the operational filtration unit. This is referred to as contact time, explains Gokhale. In municipal-scale or industrial-scale water treatment systems, contact times are usually less than 20 minutes and can be as short as five minutes. 

      “But as people have been trying to target these emerging micropollutants of concern, they realized they can’t get to sufficiently low concentrations on the same time scales as conventional contaminants,” Gokhale says. “Most technologies focus only on specific molecules or specific classes of molecules. So, you have whole technologies which are focusing only on PFAS, and then you have other technologies for lead and metals. When you start thinking about removing all of these contaminants from water, you end up with designs which have a very large number of unit operations. And that’s an issue because you have plants which are in the middle of large cities, and they don’t necessarily have space to expand to increase their contact times to efficiently remove multiple micropollutants,” he adds.

      Since zwitterionic molecules possess unique properties that confer high porosity, the researchers have been able to engineer a system for quicker uptake of micropollutants from water. Tests show that the hydrogels can eliminate six chemically diverse micropollutants at least 10 times faster than commercial activated carbon. The system is also compatible with a diverse set of materials, making it multifunctional. Micropollutants can bind to many different sites within the hydrogel platform: organic micropollutants bind to the micelles or surfactants while inorganic micropollutants bind to the zwitterionic molecules. Micelles, surfactants, zwitterionic molecules, and other chelating agents can be swapped in and out to essentially tune the system with different functionalities based on the profile of the water being treated. This kind of “plug-and-play” addition of various functional agents does not require a change in the design or synthesis of the hydrogel platform, and adding more functionalities does not take away from existing functionality. In this way, the zwitterionic-based system can rapidly remove multiple contaminants at lower concentrations in a single step, without the need for large, industrial units or capital expenditure. 

      Perhaps most importantly, the particles in the Doyle group’s system can be regenerated and used over and over again. By simply soaking the particles in an ethanol bath, they can be washed of micropollutants for indefinite use without loss of efficacy. When activated carbon is used for water treatment, the activated carbon itself becomes contaminated with micropollutants and must be treated as toxic chemical waste and disposed of in special landfills. Over time, micropollutants in landfills will reenter the ecosystem, perpetuating the problem.

      Arjav Shah, a PhD-MBA candidate in MIT’s Department of Chemical Engineering and the MIT Sloan School of Management, respectively, recently joined the team to lead commercialization efforts. The team has found that the zwitterionic hydrogels could be used in several real-world contexts, ranging from large-scale industrial packed beds to small-scale, portable, off-grid applications — for example, in tablets that could clean water in a canteen — and they have begun piloting the technology through a number of commercialization programs at MIT and in the greater Boston area.

      The combined strengths of each member of the team continue to drive the project forward in impactful ways, including undergraduate students like Andre Hamelberg, the third author on the Nature Water paper. Hamelberg is a participant in MIT’s Undergraduate Research Opportunities Program (UROP). Gokhale, who is also a J-WAFS Fellow, provides training and mentorship to Hamelberg and other UROP students in the lab.

      “We see this as an educational opportunity,” says Gokhale, noting that the UROP students learn science and chemical engineering through the research they conduct in the lab. The J-WAFS project has also been “a way of getting undergrads interested in water treatment and the more sustainable aspects of chemical engineering,” Gokhale says. He adds that it’s “one of the few projects which goes all the way from designing specific chemistries to building small filters and units and scaling them up and commercializing them. It’s a really good learning opportunity for the undergrads and we’re always excited to have them work with us.”

      In four years, the technology has been able to grow from an initial idea to a technology with scalable, real-world applications, making it an exemplar J-WAFS project. The fruitful collaboration between J-WAFS and the Doyle lab serves as inspiration for any MIT faculty who may want to apply their research to water or food systems projects.

      “The J-WAFS project serves as a way to demystify what a chemical engineer does,” says Doyle. “I think that there’s an old idea of chemical engineering as working in just oil and gas. But modern chemical engineering is focused on things which make life and the environment better.” More

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      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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      Using soap to remove micropollutants from water

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      Imagine millions of soapy sponges the size of human cells that can clean water by soaking up contaminants. This simplistic model is used to describe technology that MIT chemical engineers have recently developed to remove micropollutants from water — a concerning, worldwide problem.

      Patrick S. Doyle, the Robert T. Haslam Professor of Chemical Engineering, PhD student Devashish Pratap Gokhale, and undergraduate Ian Chen recently published their research on micropollutant removal in the journal ACS Applied Polymer Materials. The work is funded by MIT’s Abdul Latif Jameel Water and Food Systems Lab (J-WAFS).

      In spite of their low concentrations (about 0.01–100 micrograms per liter), micropollutants can be hazardous to the ecosystem and to human health. They come from a variety of sources and have been detected in almost all bodies of water, says Gokhale. Pharmaceuticals passing through people and animals, for example, can end up as micropollutants in the water supply. Others, like endocrine disruptor bisphenol A (BPA), can leach from plastics during industrial manufacturing. Pesticides, dyes, petrochemicals, and per-and polyfluoroalkyl substances, more commonly known as PFAS, are also examples of micropollutants, as are some heavy metals like lead and arsenic. These are just some of the kinds of micropollutants, all of which can be toxic to humans and animals over time, potentially causing cancer, organ damage, developmental defects, or other adverse effects.

      Micropollutants are numerous but since their collective mass is small, they are difficult to remove from water. Currently, the most common practice for removing micropollutants from water is activated carbon adsorption. In this process, water passes through a carbon filter, removing only 30 percent of micropollutants. Activated carbon requires high temperatures to produce and regenerate, requiring specialized equipment and consuming large amounts of energy. Reverse osmosis can also be used to remove micropollutants from water; however, “it doesn’t lead to good elimination of this class of molecules, because of both their concentration and their molecular structure,” explains Doyle.

      Inspired by soap

      When devising their solution for how to remove micropollutants from water, the MIT researchers were inspired by a common household cleaning supply — soap. Soap cleans everything from our hands and bodies to dirty dishes to clothes, so perhaps the chemistry of soap could also be applied to sanitizing water. Soap has molecules called surfactants which have both hydrophobic (water-hating) and hydrophilic (water-loving) components. When water comes in contact with soap, the hydrophobic parts of the surfactant stick together, assembling into spherical structures called micelles with the hydrophobic portions of the molecules in the interior. The hydrophobic micelle cores trap and help carry away oily substances like dirt. 

      Doyle’s lab synthesized micelle-laden hydrogel particles to essentially cleanse water. Gokhale explains that they used microfluidics which “involve processing fluids on very small, micron-like scales” to generate uniform polymeric hydrogel particles continuously and reproducibly. These hydrogels, which are porous and absorbent, incorporate a surfactant, a photoinitiator (a molecule that creates reactive species), and a cross-linking agent known as PEGDA. The surfactant assembles into micelles that are chemically bonded to the hydrogel using ultraviolet light. When water flows through this micro-particle system, micropollutants latch onto the micelles and separate from the water. The physical interaction used in the system is strong enough to pull micropollutants from water, but weak enough that the hydrogel particles can be separated from the micropollutants, restabilized, and reused. Lab testing shows that both the speed and extent of pollutant removal increase when the amount of surfactant incorporated into the hydrogels is increased.

      “We’ve shown that in terms of rate of pullout, which is what really matters when you scale this up for industrial use, that with our initial format, we can already outperform the activated carbon,” says Doyle. “We can actually regenerate these particles very easily at room temperature. Nearly 10 regeneration cycles with minimal change in performance,” he adds.

      Regeneration of the particles occurs by soaking the micelles in 90 percent ethanol, whereby “all the pollutants just come out of the particles and back into the ethanol” says Gokhale. Ethanol is biosafe at low concentrations, inexpensive, and combustible, allowing for safe and economically feasible disposal. The recycling of the hydrogel particles makes this technology sustainable, which is a large advantage over activated carbon. The hydrogels can also be tuned to any hydrophobic micropollutant, making this system a novel, flexible approach to water purification.

      Scaling up

      The team experimented in the lab using 2-naphthol, a micropollutant that is an organic pollutant of concern and known to be difficult to remove by using conventional water filtration methods. They hope to continue testing with real water samples. 

      “Right now, we spike one micropollutant into pure lab water. We’d like to get water samples from the natural environment, that we can study and look at experimentally,” says Doyle. 

      By using microfluidics to increase particle production, Doyle and his lab hope to make household-scale filters to be tested with real wastewater. They then anticipate scaling up to municipal water treatment or even industrial wastewater treatment. 

      The lab recently filed an international patent application for their hydrogel technology that uses immobilized micelles. They plan to continue this work by experimenting with different kinds of hydrogels for the removal of heavy metal contaminants like lead from water. 

      Societal impacts

      Funded by a 2019 J-WAFS seed grant that is currently ongoing, this research has the potential to improve the speed, precision, efficiency, and environmental sustainability of water purification systems across the world. 

      “I always wanted to do work which had a social impact, and I was also always interested in water, because I think it’s really cool,” says Gokhale. He notes, “it’s really interesting how water sort of fits into different kinds of fields … we have to consider the cultures of peoples, how we’re going to use this, and then just the equity of these water processes.” Originally from India, Gokhale says he’s seen places that have barely any water at all and others that have floods year after year. “There’s a lot of interesting work to be done, and I think it’s work in this area that’s really going to impact a lot of people’s lives in years to come,” Gokhale says.

      Doyle adds, “water is the most important thing, perhaps for the next decades to come, so it’s very fulfilling to work on something that is so important to the whole world.” More