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Presentation Slides

Abstracts

“Biological Stabilizers for Double-Base Propellants” by Dr. David E. Graham (WP20-1151)
The stabilizers used in solid propellants efficiently capture nitrogen oxides released during nitrocellulose and nitroglycerin decomposition, preventing autoignition. However, these reactions produce a mixture of chemicals that includes potentially carcinogenic N-nitrosamines. This project addresses the potential human health and environmental challenges caused by these compounds during the propellant lifecycle, including production waste disposal, surveillance, and demilitarization activities, by identifying biochemicals that react efficiently with nitrogen oxide radicals and acids, stabilizing propellant formulations without forming hazardous N-nitrosamine products. In this project, synthetic biology is used to produce lead candidate biochemicals for biomanufacturing with the goal of developing efficient and flexible production platforms for a secure supply chain. The project team used computational chemistry to screen a large number of biological antioxidants and identified biochemicals that are predicted to tightly bind nitrogen oxides released during propellant decomposition. Predictions were tested in the laboratory with small-scale nitration and nitrosation assays, and results informed preliminary assessments of environmental health and human impacts. Top-performing biochemicals will be mixed with nitrocellulose and nitroglycerin to measure compatibility and stabilizer efficacy through mass loss and heat flow calorimetry tests. A baseline lifecycle will be developed to quantify potential benefits during the in-service life of a new propellant formulation. This presentation will discuss the production of biochemical candidates and assessment of their performance in binding nitrogen oxides during propellant decomposition. Planned future work will also be discussed.

“Purification of Ammonium-Nitrate Solution (ANSOL) by Electrochemical Removal of Nitramine Explosives and Chromium” by Dr. Philip Larese-Casanova (WP21-1126)
Ammonium nitrate solution (ANSOL), the wastewater produced from the manufacturing of nitramine munitions, represents a recoverable and potentially economically viable resource if its hazardous components could be removed, particularly the nitramine compounds 1,3,5-trinitro-1,3,5-triazine (RDX) and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX), trace metals such as chromium, and residual alkylamine compounds. To meet the need for improved, cost-effective purification strategies for ANSOL, this project focuses on developing flow-through electrochemical reactors that generate reductants in situ for nitramine transformation and iron-based reactors that provide reactive iron complexes or surfaces for chromium removal. This presentation will discuss results of a demonstration of electrochemical reduction of RDX within ANSOL using a flow-through reactor featuring a cathode composed of inexpensive stainless steel wire mesh disks operated at low power with no chemical addition. A flow-through electrocoagulation column reactor can effectively remove dissolved chromium from ANSOL using a corroding iron metal anode, although an iron hydroxide sludge is produced which requires further treatment. Zero-valent iron packed with sand within a flow-through column is also an effective adsorbent for chromium. The alkylamine compounds methylamine and dimethylamine can be removed from ANSOL using a batch adsorption process utilizing common water treatment polymeric resins such as Optipore L493. The developed technology is expected to produce an ammonium nitrate solution free of toxic substances.

Speaker Biographies

Dr. David Graham is a Senior Research Scientist in Biosciences at Oak Ridge National Laboratory in Oak Ridge, Tennessee. He has led SERDP projects focused on identifying new enzymes that catalyze nitration reactions for energetic materials and stabilizing nitrate ester compositions using bioproducts. Dr. Graham’s work in microbial biochemistry spans fields from basic to applied research, building fundamental understanding at the interfaces of disciplines, collaborating to construct predictive models based on laboratory and field data, and applying biotechnology to national and global problems. Recent research topics include arctic biogeochemistry to predict greenhouse gas feedback on warming, bioproduction of organic and inorganic materials from renewable feedstocks, and detection of chemical and biological threats using novel sensors. He has published more than 110 papers and reports on microbial biology and analytical biochemistry. Dr. Graham received an associate degree in biological sciences and economics from Cornell University, and master’s and doctoral degrees in microbiology from the University of Illinois at Urbana-Champaign.

Dr. Philip Larese-Casanova is an Associate Professor in the Department of Civil and Environmental Engineering at Northeastern University in Boston, Massachusetts. His primary area of research lies in the broad areas of physical, chemical, and electrochemical transformation processes of metallic, inorganic, and organic water pollutants, with applications to groundwater environments and engineered unit operations. He has served as principal and co-principal investigator of projects funded by SERDP and NSF investigating transformation reactions of selenium and chromium oxyanions, iron oxides, quantum dot nanoparticles, and energetic compounds. His projects since 2018 focus on addressing industrial wastewater problems using electrochemical solutions that involve low energy inputs and low to no chemical additives. He is the recipient of the NSF CAREER Award, Association of Environmental Engineering and Science Professors Distinguished Service Award, and Environmental Science and Technology Excellence in Review Award. Dr. Larese-Casanova received a doctoral degree in environmental engineering from the University of Iowa.