Faculty and students of the Georgia Tech Renewable Bioproducts Institute were active participants at the TAPPINano 2024 conference held in Atlanta, GA on June 10-14, 2024. The Renewable Bioproducts Institute was a gold sponsor of the event that focused on the topic - Building from the Bottom Up: Shaping a Sustainable World using Renewable Nanomaterials.

RBI’s Executive Director Carson Meredith was a keynote presenter at the conference. Conference attendees had an opportunity to participate in an academic tour of RBI.

During a session on water treatment and recovery, Zhaohui Tong, Associate Professor and RBI lead for Waste Valorization in Food-Energy-Water and Yongsheng Chen, Bonnie W. and Charles W. Moorman IV Professor in the School of Civil and Environmental Engineering participated and presented their work on nano-triboelectric cellulose membrane sensors for heavy metal ions removal and detection and next generation nano filtration membranes via machine learning-screened novel monomers respectively.

During the lunch presentation on June 11, Carson Meredith, Professor at the School of Chemical and Biomolecular Engineering, and executive director of RBI, presented on the topic “Cellulose nano materials at the Renewable Bioproducts Institute: Two decades of partnerships and progress.”

Xiaoqing Yu, graduate student at the Woodruff School in Georgia Tech presented her paper on de-wrinkling for papers coated with cellulose nanocrystal and modified celluloses.

Georgia Tech graduate students and RBI Fellows, Kim Anh Pham, Jonathan Rhone and Javaz Rolle participated in a session on cellulose based coatings, and presented their work on sustainable oxygen barrier coatings for paper based on anionic and cationic cellulose derived materials, cellulose nanocrystal coated glass fiber-epoxy composites: interfacial and tensile properties, and durable bio-based coatings for packaging applications.

Finally, during a session on CNF & MFC Sheets and Films, Fariha Rubaiya, RBI Fellow presented her work on out-of-plane auxecity in cellulose nanofibril films.

The Bark Rhythms exhibit continues at the Robert C. Williams Museum of Papermaking through August. It features historical examples of hand-beaten bark papers, barkcloths, and traditional beaters, paired with the work of contemporary artists from global communities who use bark fiber materials and techniques. Photos taken June 24 by Joya Chapman.

Chaouki Abdallah, Georgia Tech's executive vice president for Research (EVPR), has been named the new president of the Lebanese American University in Beirut.  

Abdallah, MSECE 1982, Ph.D. ECE 1988, has served as EVPR since 2018; in this role, he led extraordinary growth in Georgia Tech's research enterprise. Through the work of the Georgia Tech Research Institute, 10 interdisciplinary research institutes (IRIs), and a broad portfolio of faculty research, Georgia Tech now stands at No. 17 in the nation in research expenditures — and No. 1 among institutions without a medical school.  

Additionally, Abdallah has also overseen Tech's economic development activities through the Enterprise Innovation Institute and such groundbreaking entrepreneurship programs as CREATE-X, VentureLab, and the Advanced Technology Development Center. 

Under Abdallah's strategic, thoughtful leadership, Georgia Tech strengthened its research partnerships with historically Black colleges and universities, launched the New York Climate Exchange with a focus on accelerating climate change solutions, established an AI Hub to boost research and commercialization in artificial intelligence, advanced biomedical research (including three research awards from ARPA-H), and elevated the Institute's annual impact on Georgia's economy to a record $4.5 billion.  

Prior to Georgia Tech, Abdallah served as the 22nd president of the University of New Mexico (UNM), where he also had been provost, executive vice president of academic affairs, and chair of the electrical and computer engineering department. At UNM, he oversaw long-range academic planning, student success initiatives, and improvements in retention and graduation rates. 

A national search will be conducted for Abdallah's replacement. In the coming weeks, President Ángel Cabrera will name an interim EVPR. 

Students in the Pulp and Paper Certification Program at Georgia Tech had real-world experiences outside the classroom this spring. Over 30 students taking the Emerging Technologies in the Manufacture of Forest Bioproducts course (CHBE/ME 4730/8803) took field trips to Greif’s Austell location and GranBio’s Thomaston facility in Georgia. The course is taught by Chris Luettgen, professor of the practice and initiative lead for the process efficiency & intensification of pulp paper packaging & tissue manufacturing initiative at Georgia Tech's Renewable Bioproducts Institute. 

At the Sweetwater Mill, one of Greif’s three paper mills in Austell, students saw the pressure cylinder machine, a pre-coater that smoothens the board for printability, and a curtain coater that makes value-added products such as one-sided chipboard packaging for retail displays. The mill runs 100% recycled fiber into stock cores, gypsum board liners, and chipboard packaging. The tour included converting the machine roll (called a parent roll) into smaller rolls that will be further converted at downstream customers’ locations. 

At the GranBio’s facility in Thomaston, Tech students were able to see a biorefinery at work where a wide variety of lignocellulosic feedstocks, including wood chips, were getting converted into multiple bioproducts. They had a firsthand look at the SEW (sulfur dioxide, ethanol, and water) process, which was quite different from the traditional kraft pulping process. It creates a highly acidic mush, with a high pH, instead of fiber, which could then be used to make biofuels and other value-added products. In addition, they were able to discuss the recent DOE award to scale their process to a 100 ton/day biomass to Sustainable Aviation Fuel (SAF).  The company explained that they were still in site selection and would be hiring engineers in the near future.

About the Pulp and Paper Certification

The College of Engineering at Georgia Tech offers a certificate program in pulp and paper. The certificate consists of 12 credit hours focused on forest bioproduct topics, including lecture- and laboratory-based courses. Since its inception in 1990, more than 100 students have completed their certification.

The foundational course in the program introduces students to the history of pulp and paper manufacturing from its origins and covers the forest bioeconomy, wood structure, chemistry, and fiber morphology, and goes through the unit operations utilized to transform lignocellulosic feedstocks into value-added products, including chemical and mechanical pulping, recycled fiber operations, chemical recovery, bleaching, stock preparation, and papermaking.

The emerging technologies course focuses on the future of bioproducts industries. Case studies on the use of biomass in the production of value-added products are covered. Included are fluff pulp and dissolving pulps, alternative fibers, specialty papers, packaging, and printed electronics, biorefining technologies, nanocellulose and bio composites, and renewable polymers.

The pulp and paper laboratory course introduces students to pulping operations, bleaching, hand sheet formation, pulp and paper physical properties, and recycled fiber. The final course allows students to pursue research on special problems under supervision from an RBI-affiliated faculty.

Blair Brettmann, associate professor, Solvay Faculty Fellow, and Raymond and Stephanie Myers Faculty Fellow in the School of Chemical and Biomolecular Engineering, co-leads the interface of polymer science and wood-based materials initiative with Will Gutekunst at Georgia Tech’s Renewable Bioproducts Institute. 

Brettmann’s current research focuses on developing technologies that enable multicomponent, rapidly customizable product design, with a specific focus on polymer systems. 

Brettmann received her Ph.D. in chemical engineering at MIT in 2012 working with the Novartis-MIT Center for Continuous Manufacturing under Bernhardt Trout. Later, she worked on polymer-based wet coatings and dispersions for various applications at Saint-Gobain Ceramics and Plastics. She went on to serve as a postdoctoral researcher in the Institute for Molecular Engineering at the University of Chicago with Matthew Tirrell. Below is a brief Q&A with Brettmann in which she discusses her research focus areas and how they influence the interface of polymer science and wood-based materials research at Georgia Tech.

• What is your field of expertise and at what point in your life did you first become interested in this area?

My expertise is in polymer science and materials design for manufacturability. I got excited about this area after my Ph.D. when I worked for Saint-Gobain and saw firsthand the challenges of bringing new products to market, especially those made of complex mixtures of materials. 

• What questions or challenges sparked your current renewable bioproducts research? What are the big issues facing your research area right now?

Sustainability of materials and process is a top priority right now across many industries, and renewable bioproducts research is helping to improve this. But it is still tough to design and scale up products made with these materials because of the heterogeneity of the raw bio-based materials and recycled materials that now serve as the raw materials. Engineers are essential to design systems that can be robust despite the heterogeneities and still produce consistent, high-quality products.

• What interests you the most in leading the research initiative on the interface of polymer science and wood-based materials? Why is your initiative important to the development of Georgia Tech’s Renewable Bioproducts research strategy?

One of the most promising directions to decrease the impact of plastics on the environment is to replace some of the synthetic plastic materials with natural products, such as cellulose from wood. My initiative aims to build better connections between polymer scientists working to design improved plastics and experts in bio-based materials to seed research that can work toward this goal. Polymers also serve as important tools to improve the properties of cellulose and wood-based products and can enable new materials with increased functionality that still have sustainable materials at their core.

• What are the broader global and social benefits of the research you and your team conduct on the interface of polymer science and wood-based materials?

We work to improve the sustainability of material products while addressing specific challenges related to manufacturing and scale-up, which can speed up the adoption of these more sustainable products in industry. We take a wide view of the problem and have even worked on a project to understand consumer choices in recycling: If people don’t recycle the material, our efforts to make recyclable products will not have an impact!

• What are your plans for engaging a wider Georgia Tech faculty pool with the broader renewable bioproducts community?

Using symposia, social events, and student-centered networking, I will bring the broad Georgia Tech Polymer Network community together with the RBI community.

• What are your hobbies?

Water polo and swimming. I train with the Atlanta Rainbow Trout, who practice at the Georgia Tech pool.

• Who has influenced you the most?

 I’m constantly learning from people around me!

When looking for an environmentally friendly and cost-effective way to clean up contaminated water and soil, Georgia Tech researchers Patricia Stathatou and Christos Athanasiou turned to yeast. A cheap byproduct from fermentation processes — e.g., something your local brewery discards in mass quantities after making a batch of beer — yeast is widely known as an effective biosorbent. Biosorption is a mass transfer process by which an ion or molecule binds to inactive biological materials through physicochemical interactions.

When they initially studied this process, Stathatou and Athanasiou found that yeast can effectively and rapidly remove trace lead — at challenging initial concentrations below one part per million — from drinking water. Conventional water treatment methods either fail to eliminate lead at these low levels or result in high financial and environmental costs to do so. In a paper published today in RSC Sustainability, the researchers show how this process can be scaled.

“If you put yeast directly into water to clean it, you will need an additional treatment step to remove the yeast from the water afterward,” said Stathatou, a research scientist at the Renewable Bioproducts Institute and an incoming assistant professor at the School of Chemical and Biomolecular Engineering. “To implement this process at scale without requiring additional separation steps, the yeast cells need a housing.”

“Additionally, because yeast is abundant— in some cases, brewers even pay companies to haul it away as a waste byproduct — this process gives the yeast a second life,” said Athanasiou, an assistant professor in the Daniel Guggenheim School of Aerospace Engineering. “It’s a plentiful low, or even negative, value resource, making this purification process inexpensive and scalable.”

To develop a housing for the yeast, Stathatou and Athanasiou partnered with MIT chemical engineers Devashish Gokhale and Patrick S. Doyle. Gokhale and Stathatou are the lead authors of this new study that demonstrates the yeast water purification process’s scalability.

“We decided to make these hollow capsules— analogous to a multivitamin pill — but instead of filling them up with vitamins, we fill them up with yeast cells,” Gokhale said. “These capsules are porous, so the water can go into the capsules and the yeast are able to bind all of that lead, but the yeast themselves can’t escape into the water.”

The yeast-laden capsules are sufficiently large, about half a millimeter in diameter, for easy separation from water by gravity. This means they can be used to make packed-bed bioreactors or biofilters, with contaminated water flowing through these hydrogel-encased yeast cells and coming out clean.

Stathatou and Athanasiou envision using these hydrogel yeast capsules in small biofilters consumers can put on their kitchen faucets, or biofilters large enough to fit municipal or industrial wastewater treatment systems. But to enable such scalability, the yeast-laden capsules’ ability to withstand the force generated by water flowing inside such systems needed to be studied as well.

To determine this, Athanasiou tested the capsules’ mechanical robustness, which is how strong and sturdy they are in the presence of waterflow forces. He found they can withstand forces like those generated by water running from a faucet, or even flows like those in water treatment plants that serve a few hundred homes. “In previous attempts to scale up biosorption with similar approaches, lack of mechanical robustness has been a common cause of failure,” Athanasiou said. “We wanted to make sure our work addressed this issue from the very beginning to ensure scalability.”

“After assessing the mechanical robustness of the yeast-laden capsules, we made a prototype biofilter using a 10-ml syringe,” Stathatou explained. “The initial lead concentration of water entering the biofilter was 100 parts per billion; we demonstrated that the biofilter could treat the contaminated water, meeting EPA drinking water guidelines, while operating continuously for 12 days.”

The researchers hope to identify ways to isolate and collect specific contaminants left behind in the filtering yeast, so those too can be used for other purposes.

“Apart from lead, which is widely used in systems for energy generation and storage, this process could be used to remove and recover other metals and rare earth elements as well,” Athanasiou said. “This process could even be useful in space mining or other space applications.”

They also would like to find a way to keep reusing the yeast. “But even if we can’t reuse yeast indefinitely, it is biodegradable,” Stathatou noted. “It doesn’t need to be put into an industrial composter or sent to a landfill. It can be left on the ground, and the yeast will naturally decompose over time, contributing to nutrient cycling.”

This circular approach aims to reduce waste and environmental impact, while also creating economic opportunities in local communities. Despite numerous lead contamination incidents across the U.S., the team’s successful biosorption method notably could benefit low-income areas historically burdened by pollution and limited access to clean water, offering a cost-effective remediation solution. “We think there’s an interesting environmental justice aspect to this, especially when you start with something as low-cost and sustainable as yeast, which is essentially available anywhere,” Gokhale says.

Moving forward, Stathatou and Athanasiou are exploring other uses for their hydrogel-yeast purification method. The researchers are optimistic that, with modifications, this process can be used to remove additional inorganic and organic contaminants of emerging concern, such as PFAS — or “forever” chemicals — from the water or the ground.

Citation: Devashish Gokhale, Patritsia M. Stathatou, Christos E. Athanasiou, and Patrick S. Doyle, “Yeast-laden Hydrogel Capsules for Scalable Trace Lead Removal from Water,” RSC Sustainability. 

DOI: https://doi.org/10.1039/D4SU00052H

Funding: Patricia Stathatou was supported by funding from the Renewable Bioproducts Institute at Georgia Tech. Devashish Gokhale was supported by the Rasikbhai L. Meswani Fellowship for Water Solutions and the MIT Abdul Latif Jameel Water and Food Systems Lab (J-WAFS).

To avoid catastrophic climate impacts, excessive carbon emissions must be addressed. At this point, cutting emissions isn’t enough. Direct air capture, a technology that pulls carbon dioxide out of ambient air, has great potential to help solve the problem.

But there’s a big challenge. For direct air capture technology, every type of environment and location requires a uniquely specific design. A direct air capture configuration in Texas, for example, would necessarily be different from one in Iceland. These systems must be designed with exact parameters for humidity, temperature, and air flows for each place.

Now, Georgia Tech and Meta have collaborated to produce a massive database, potentially making it easier and faster to design and implement direct air capture technologies. The open-source database enabled the team to train an AI model that is orders of magnitude faster than existing chemistry simulations. The project, named OpenDAC, could accelerate climate solutions the planet desperately needs.

The team’s research was published in ACS Central Science, a journal of the American Chemical Society.

“For direct air capture, there are many ideas about how best to take advantage of the air flows and temperature swings of a given environment,” said Andrew J. Medford, associate professor in the School of Chemical and Biomolecular Engineering (ChBE) and a lead author of the paper. “But a major problem is finding a material that can capture carbon efficiently under each environment’s specific conditions.”

Their idea was to “create a database and a set of tools to help engineers broadly, who need to find the right material that can work,” Medford said. “We wanted to use computing to take them from not knowing where to start to giving them a robust list of materials to synthesize and try.”

Containing reaction data for 8,400 different materials and powered by nearly 40 million quantum mechanics calculations, the team believes it’s the largest and most robust dataset of its kind.

Building a Partnership (and a Database)

Researchers with Meta’s Fundamental AI Research (FAIR) team were looking for ways to harness their machine learning prowess to address climate change. They landed on direct air capture as a promising technology and needed to find a partner with expertise in materials chemistry as it relates to carbon capture. They went straight to Georgia Tech.

David Sholl, ChBE professor, Cecile L. and David I.J. Wang Faculty Fellow, and director of Oak Ridge National Laboratory’s Transformational Decarbonization Initiative, is one of the world’s top experts in metal-organic frameworks (MOFs). These are a class of materials promising for direct air capture because of their cagelike structure and proven ability to attract and trap carbon dioxide. Sholl brought Medford, who specializes in applying machine learning models to atomistic and quantum mechanical simulations as they relate to chemistry, into the project.

Sholl, Medford, and their students provided all the inputs for the database. Because the database predicts the MOF interactions and the energy output of those interactions, considerable information was required.

They needed to know the structure of nearly every known MOF — both the MOF structure by itself and the structure of the MOF interacting with carbon dioxide and water molecules.

“To predict what a material might do, you need to know where every single atom is and what its chemical element is,” Medford said. “Figuring out the inputs for the database was half of the problem, and that’s where our Georgia Tech team brought the core expertise.”

The team took advantage of large collections of MOF structures that Sholl and his collaborators had previously developed. They also created a large collection of structures that included imperfections found in practical materials.

The Power of Machine Learning

Anuroop Sriram, research engineering lead at FAIR and first author on the paper, generated the database by running quantum chemistry computations on the inputs provided by the Georgia Tech team. These calculations used about 400 million CPU hours, which is hundreds of times more computing than the average academic computing lab can do in a year.

FAIR also trained machine learning models on the database. Once trained on the 40 million calculations, the machine learning models were able to accurately predict how the thousands of MOFs would interact with carbon dioxide.

The team demonstrated that their AI models are powerful new tools for material discovery, offering comparable accuracy to traditional quantum chemistry calculations while being much faster. These features will allow other researchers to extend the work to explore many other MOFs in the future.

“Our goal was to look at the set of all known MOFs and find those that most strongly attract carbon dioxide while not attracting other air components like water vapor, and using these highly accurate quantum computations to do so,” Sriram said. “To our knowledge, this is something no other carbon capture database has been able to do.”

Putting their own database to use, the Georgia Tech and Meta teams identified about 241 MOFs of exceptionally high potential for direct air capture.

Moving Forward With Impact

“According to the UN and most industrialized countries, we need to get to net-zero carbon dioxide emissions by 2050,” said Matt Uyttendaele, director of Meta’s FAIR chemistry team and a co-author on the paper. “Most of that must happen by outright stopping carbon emissions, but we must also address historical carbon emissions and sectors of the economy that are very hard to decarbonize — such as aviation and heavy industry. That’s why CO2 removal technologies like direct air capture must come online in the next 25 years.” 

While direct air capture is still a nascent field, the researchers say it’s crucial that groundbreaking tools — like the OpenDAC database made available in the team’s paper — are in development now. 

“There is not going to be one solution that will get us to net-zero emissions,” Sriram said. “Direct air capture has great potential but needs to be scaled up significantly before we can make a real impact. I think the only way we can get there is by finding better materials.”

The researchers from both teams hope the scientific community will join the search for suitable materials. The entire OpenDAC dataset project is open source, from the data to the models to the algorithms.

“I hope this accelerates the development of negative-emission technologies like direct air capture that may not have been possible otherwise,” Medford said. “As a species, we must solve this problem at some point. I hope this work can contribute to getting us there, and I think it has a real shot at doing that.”

Note: Georgia Tech ChBE graduate students Sihoon Choi, Logan Brabson, and Xiaohan Yu made major contributions and are co-authors of the paper.

Citation: A. Sriram et al, The Open DAC 2023 Dataset and Challenges for Sorbent Discovery in Direct Air Capture, ACS Central Science (2024).

DOI: https://doi.org/10.1021/acscentsci.3c01629