Progress 01/01/24 to 12/31/24
Outputs
Target Audience:The target audience includes the readership of the scientific journals listed below,professional conferences attendees, and workshop attendees. The journals include Carbon, with a readership of scientists and engineers among many disciplines who use carbon-based materials; ACS Sustainable Chemistry and Engineering, with an audience interested in sustainable chemistry; ChemistryOpen, with a broad audience interested in chemistry; and ACS Omega, with a broad audience interested in chemistry, and Journal of Physcial Chemistry, with a broad readership across computational and analytical chemistry disciplines. The conferences and workshops include the American Chemical Society (ACS) and the American Institute of Chemical Engineers, which include chemists, material scientists, and many other scientists from cross-disciplinary fields. Additionally, I spoke to participants at the Sustainable Pulp and Paper Conference, Frontiers in Biorefining, Society of Plastic Engineers ANTEC,EXCET Workshop - U.S.-Japan Exchange Program for Green Growth Collaboration through Clean Energy Technologies, and TVA's Connected Communities Conference. Further, industrial producers of lignin and fractionation technology (Domtar, Valmet, Sweetwater, Genera), producers of carbon materials (General Graphene), and industrial emitters of carbon dioxide (Eastman Chemical, Volkswagen, TVA, Ford, Nissan), and other end users are the target audiences. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?2 graduate students and 6undergraduates have worked on the project throughout the year. 1. 3 undergraduates learned computational modeling methods. 2. Undergraduates received numerous honors working on this research. They were able to travel and present at TMS, ACS, and SPE ANTEC. The undergraduates were involved in publishing papers and submitting invention disclosures (Michael Broud). How have the results been disseminated to communities of interest?We have disseminated results to: 1. The scientific community through presentations at ACS, AIChE, TMS, and Frontiers in Biorefining. 2. We have spoken to industry leaders at TVA, EPRI, VW, and others about adopting the technology. What do you plan to do during the next reporting period to accomplish the goals?For the next reporting period, we are focused on 4 main areas. Produce a more accurate physicochemical model of the carbon quantum dot structure to enhance our computational models. Analytically quantify the adsorption capacity on electrospun carbonfibers and CQD decorated surfaces. Incorporate project results into interdisciplinary senior capstone projects across several engineering disciplines, materials science, biosystems, and mechanical engineering. Increase the selectivity of CO2 sorption onto lignin based carbon surfaces.
Impacts
What was accomplished under these goals?
1. We have made activated lignin carbon fibers and carbon quantum dots. We can control the sizeand the amount of nitrogen doping. This has an impact on visible light emissions and selectivity. 2. Progress has been made to assess the structure of the carbon quantum dots from lignin. We observe differences in the crystal structure when comparing nitrogen doped versus undoped. This is ongoing work. Preliminary results suggest that the lignin surface greatly enhances CO2 selectivity. 3. Computational methods verify enhanced CO2 selectivity in mixed gas streams. The architecture of carbon dots enhances the sorption capacity of the gases. 4. We have scaled the ability to selectively produce lignin suitable for electrospinning. We are able to repeatably produce carbon fiber mats from the materials. Models of lignin based carbon surfaces derived from x-ray diffraction are the basis for our current state of the art modeling methods that demonstrate higher than proposed selectivities.
Publications
- Type:
Peer Reviewed Journal Articles
Status:
Published
Year Published:
2024
Citation:
M. Samandari, M.T. Broud, D.P. Harper, D.J. Keffer, Carbon Dioxide Capture on Oxygen- and Nitrogen-Containing Carbon Quantum Dots., J. Phys. Chem. B. 128 (2024) 85308545. https://doi.org/10.1021/acs.jpcb.4c04247.
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Progress 01/01/23 to 12/31/23
Outputs
Target Audience:The target audience includes the readership of the journals listed below and the professional conferences and workshop attendees. The journals include Carbon, with a readership of scientists and engineers among many disciplines who use carbon-based materials; ACS Sustainable Chemistry and Engineering, with an audience interested in sustainable chemistry; ChemistryOpen, with a broad audience interested in chemistry; and ACS Omega, with a broad audience interested in chemistry.The conferences and workshops include the American Chemical Society (ACS) and the American Institute of ChemicalEngineers, which include chemists, material scientists, and many other scientists from cross-disciplinary fields. Further, industrial producers of lignin and fractionation technology (Domtar, Valmet, Sweetwater, Genera), producers of carbon materials(General Graphene), and industrial emitters of carbon dioxide (Eastman Chemical, Volkswagen, TVA, Ford, Nissan), and other end users are the target audiences. Changes/Problems:The kinetic studies are delayed because of equipment delivery delays. A key aspect of this project is sorption/desorption studies of materials made in the lab, which relies on a thermogravimetric analyzer. This piece of equipment has been replaced four times because of manufacturing defects. The latest version is scheduled for delivery in June 2024. Also, a lab-scale digester used for lignin fractionation delayed delivery by over six months. Further, our laboratory fluidized bed sand bath reactor is broken and needs repairs, which delays our CQD production. The result is an almost 12 month delay in experimental results. What opportunities for training and professional development has the project provided?Students working on the project were provided opportunities for continued training enabled by the project. Two undergraduates received prestigious SULI internships at Oak Ridge National Laboratory, working in battery recycling and computational analysis of neutron scattering data, respectively. One student gave a formal presentationof his work at the AIChE National Convention. Another student presented his work at TMS and ACS national meetings. He won first place in the undergraduate research category at TMS and the TMS Materialia Acta Scholarship. He was also selected as the outstanding Materials Science Junior at UT and recipient of the prestigious Barry Goldwater Scholarship, the highest honor for a science and engineering undergraduate in the U.S. His work also led to an invitation to visit Tennessee's congressional delegation in Washington D.C. His research experience led to acceptance into the graduate program at NC State University. How have the results been disseminated to communities of interest?Results have been published and presented at national meetings (reported earlier). Invention disclosures and provisional patents have been filed (one published). Drs. Harper and Keffer had numerous conversations with external companies regarding the technology. Dr. Harper presented this work to the Japanese Business Roundtable with manufacturers present, including Denso, Nissan, Toyota, JTEKT, and Bridgestone. I presented the research to other TN manufacturers, such as General Graphene, VW, and TVA. The work was presented at the TN Advanced Manufacturing Showcase and will be incorporated into new carbon capture technology by VW. What do you plan to do during the next reporting period to accomplish the goals?For the next reporting period,we are focused on 4 main areas. Produce a more accurate physicochemical model of the carbon quantum dot structure to enhance our computational models. Analytically quantify the adsorption capacity of the activated fibers and CQD decorated surfaces. Improve our ability to scale and activate the carbon mats produced from lignin. Incorporate project results into interdisciplinary senior capstone projects across several engineering disciplines, materials science, biosystems, and mechanical engineering.
Impacts
What was accomplished under these goals?
We have achieved significant progress toward addressing USDA's and this project's goals to increase the value of underused nonfood products and lignin, reduce carbon emissions, and improve rural economies. We made progress toward accomplishing our four targeted goals. We made reproduciblelignin-carbon fiber nonwoven mats and carbon quantum dots (CQDs), achieving the same functionality and chemical composition. We are working to reliably quantify the morphology of these materials. We have performed a kinetic evaluation of the gas sorption/desorption of CO2 for activated carbon mats. We investigated several methods to disperse CQDs on substrates. The results confirm microscopyand spectroscopic results that show improved distribution from simple drop coating to dispersion with ultrasonic air atomized spray application. Adsorption/desorption kinetic studies, along with morphology and cyclability, will continue. We computed the binding energies of the gas molecules in the atmosphere and combustion gases in pure and mixed streams. The surfaces with CQDs show improved CO2 selectivity over N2, O2, CO, and H2O. The result is more profound in mixed gas streams. Analytical cycling demonstrates physical sorption and full reversibility for enhanced life spans for the materials. Multiple CQD structures, with and without nitrogen doping, and terminal groups were investigated experimentally and computationally. Large differences in selectivity were not observed, but the results were positive. Kinetic studies are ongoing and incomplete at this time. Scanning Transmission Electron Microscopy (STEM) and electron energy loss spectroscopy will continue to determine CQD atomic structure to inform computational models. Total X-ray scatteringanalysis will be performed in the coming months, building on a method funded under a previous USDA grant to determine the unambiguous carbon structure of the CQDs.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
Michael T. Broud, Mohsen Samandari, Lu Yu, David P. Harper, and David. J Keffer. Selective carbon dioxide binding on carbon quantum dots. The Journal of Physical Chemistry C, 127(28):1363913650, 2023. https://doi.org/10.1021/acs.jpcc.3c02885
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2023
Citation:
Selective CO2 Sequestration in Lignin-based Carbon Composite Membranes Via Nanoscale Engineered Quadrupole Moments of Adsorption Sites, USDA Headquarters, Kansas City, MO (National, 2023)
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Progress 01/01/22 to 12/31/22
Outputs
Target Audience:The target audience includes the readership of the journals listed below and theprofessional conferences and workshop attendees. The journals includeCarbon, with a readership of scientists and engineers among many disciplines who use carbon-based materials, ACS Sustainable Chemistry and Engineering, with an audience interested in sustainable chemistry, ChemistryOpen, with a broad audience interested in chemistry; andACS Omega, with a broad audience interested in chemistry. The conferences and workshops include the American Chemical Society (ACS) andtheAmerican Institute of Chemical Engineers,whichinclude chemists, material scientists, and many other scientists from cross-disciplinary fields. Further, industrial producers of ligninand fractionation technology(Domtar, Valmet, Sweetwater), producers of carbon materials (General Graphene), and industrialemitters of carbon dioxide(Eastman Chemical, Volkswagen, TVA),andotherend users are the target audiences. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Opportunities for training: Funds have helped 4 graduate students and 4 undergraduate students gain research experience. Provided training opportunities: 1. An undergraduate student to learn molecular modeling, attend a summer research experience for undergraduates, and give an oral presentation at the American Institute for Chemical Engineers. 2. A graduate student, Lu Yu, was able to finish her degree and conductresearch on carbon quantum dots at the Center for Nanophase Materials Science. How have the results been disseminated to communities of interest?Results have been disseminated to communities through presentations at workshops, such as theUT Manufacturing and Design Workshop, and the Biomaterials workshop that Dr. Harper organized. Additionally, ongoing talks with companies and organizations, such as General Graphene and TVA, are occurring to develop more renewable systems for CO2 capture by functionalizing low-cost carbon substrates. What do you plan to do during the next reporting period to accomplish the goals?1. We plan to test the absorption capacity of carbon surfaces with varying CQD concentrations. We will also optimize the surface area chemical composition based on adsorption from the thermogravimetric analysis. 2. We plan to develop methods to investigate the chemical structure of the CQDsto inform the computational models. 3. Multi-carbon quantum dots and graphitic dots will be investigated computationally. We will determine the spacing necessary to maximize the selectivity of the quantum dots. 4. A model system of carbon will be studied based on previous computational results. We will predict amount of gas adsorbed, the adsorbance rate, and the sorption capacity for a multi-gas and multi-dot system.
Impacts
What was accomplished under these goals?
Mitigating climate change's most extreme potential effects from fossil fuel burning requires unprecedented global carbon sequestration. The materials used for carbon capture must be renewable, economically feasible, abundant, and recyclable, able to recover the adsorbed gas. Carbon quantum dots (CQD) are evaluated as materials to decorate the interior pore space of model carbon surfaces to achieve selective carbon dioxide adsorption from gas mixtures. Objective 1, make lignin-based activated carbon fibers and carbon quantum dots: We accomplished making lignin-based fibers. Electrospinning of fibers has been inconsistent because of environmental conditions in the lab. Carbon quantum dot production has increased. We can produce CQD's with and without nitrogen doping from a top-down approach. Preliminary results demonstrated that a chemically activated lignin surface has higher sorption capacity than commercial carbon materials. ` Objective 2, determine the physicochemical composition of lignin carbon fibers: We have activated melt-blown hardwood lignin carbon fibers. We used an activation procedure that was optimized for softwood-based lignin. The result was only marginally successful. Objective 3, compute and evaluate selective binding: We used classical molecular dynamics (MD) simulation to evaluate the effect of CQD size and composition on the selectivity of CO2 relative to N2 and O2. The CQDs are modified through nitrogen doping the interior aromatic structure or functionalization of the edges with amine groups. CQDs show selective adsorption for CO2 relative to N2 and O2 in all cases. The magnitude of the selectivity is a function of CQD size and the amount of doping and functionalization. In this exploratory study, a maximum CO2:N2 selectivity of 4.3 and CO2:O2 selectivity of 3.1 were obtained on isolated CQDs at 300 K without structural optimization. This preliminary computational study sets the framework for optimizing the CQD atomic architecture on a CQD/AC adsorbent. Objective 4, assess membrane performance from the model: Currently, this work is waiting on further model development.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Broud, M.T., Yu, L., Keffer, D.J., Harper, D.P., Investigation of Preferential CO2 Binding on Lignin-derived Carbon Quantum Dots Through Molecular Dynamics Simulations , AIChE Annual Meeting, Nov. 2022, Phoenix, AZ.
- Type:
Journal Articles
Status:
Submitted
Year Published:
2022
Citation:
Broud, M.T., Yu, L., Harper, D.P., Keffer, D.J., Selective Carbon Dioxide Binding On Carbon Quantum Dots , under revision, 2023.
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