Katharine Maher, Ph.D. - US grants

This project will develop a preliminary design and work-breakdown-structure for a large-scale subsurface experimental facility to investigate coupled thermal-hydrological-mechanical-chemical-biological processes in fractured rock at depth. The experiment will be part of the proposed Deep Underground Science and Engineering Laboratory (DUSEL) in the Homestake Mine, South Dakota. Many natural and engineered earth systems involve coupling of multiple processes in rocks that vary across a wide range of scales. The most pervasive process in the Earth?s crust that gives rise to strongly coupled phenomena is the flow of fluids (water, CO2, hydrocarbons, magmas) through fractured heated rock under stress. Understanding changes in the reactivity, deformability, life-supporting and transport properties of rocks that fluids infiltrate is important in a broad range of geological engineering and geological science endeavors. Despite this fundamental importance, the interactions remain poorly understood.

The project will: (1) Determine properties of Homestake rocks: geological, geochemical, mechanical, thermal, isotopic, and reactivity. (2) Upscale these data to elucidate transport mechanisms (conductive versus convective), natural reaction rates in fractures, and microbial community evolution. (3) Evaluate monitoring strategies, in-situ probes and sampling methods, and necessary measurements. (4) Select a candidate site for the evaluating coupled processes. (5) Develop a work-breakdown-structure. (6) Develop a coupled numerical model to evaluate potential effects on the rock mass and optimal heater configuration, power, and monitoring borehole orientations.

The models and insight from these experiments will have broad applicability to engineered systems, e.g., enhanced geothermal systems, CO2 sequestration and subsurface contaminant transport. Educational outreach will involve facility tours and a traveling benchscale ?mock-up? demonstration experiment.

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

There are relatively few records that reflect large-scale changes in atmospheric circulation during the last glacial-interglacial cycle, and very few with sufficient temporal resolution and/or continuity to resolve the timing and sequence of changes. To understand how these changes occurred in the past, terrestrial climate records that are sensitive to changes in precipitation are necessary. Although there are a substantial number of short-term high-resolution terrestrial paleoclimate records, there are relatively few records that span the last few glacial-interglacial cycles. These sparse records have proven insufficient to resolve the mechanisms behind the large-scale shifts in effective moisture that occurred during glacial-interglacial transitions. In addition, it has been challenging to resolve the effects of temperature and changes in moisture source from changes in the amount of precipitation using existing proxy data.

Intellectual merit: This project will develop high-spatial resolution analytical approaches using secondary ion mass spectrometry (SIMS) to provide spatially and temporally continuous records of climate and atmospheric circulation over the last few glacial-interglacial transitions (10 to 200 ka) using pedogenic opal. 230Th-U SIMS dating will be complimented by the development of multi-isotope proxies in order to develop high-temporal spatial resolution records that connect to form a regional grid, and are thus uniquely capable of reflecting past changes in atmospheric circulation. Specifically, the investigator will test the hypothesis that uranium isotopic and trace element variations in dated pedogenic opal provide a robust archive of paleoprecipitation. Changes in moisture sources will be detected using δ18O, and changes in weathering intensity will be assessed using δ30Si. The existing geochronological records from soils show variations in initial (234U/238U) activity ratios and trace elements over the last 200 ka. The investigator hypothesizes that initial (234U/238U) variations are recording changes in past rainfall amounts. However, the exact mechanism for these variations must be more closely examined before quantitative data can be developed. Therefore prior to expanding her network of soil sites, she proposes to test the concordance of the initial (234U/238U) values and the validity of the U-series proxy using the modern soil system. Development and validation of the U-series proxy would enable paleoclimate information to be extracted directly from the geochronologic measurements of soils and could potentially be extended to speleothem.

Broader impacts: This research will have important implications for our understanding of the rates and mechanisms of climate change in terrestrial environments. By working with the climate modeling community, the data and network of sites will provide unique and much needed calibration data that will greatly improve the ability to predict and understand the current changes in atmospheric circulation. As the samples she plans to analyze are modern analogues for paleosols, the approaches and understanding she develops will also have important implications for these materials and may enable new records to be developed at key intervals back in Earth?s history. To make her records available, she will host a database of published U-series data at Stanford, and work with other scientists to include existing records. Secondly, she will work with the outreach program in the School of Earth Sciences at Stanford. She plans to: 1) accept high school interns to work with her in the field and in her laboratory, 2) work with the K-12 program ?Expanding Your Horizons? to develop a module describing the climate system, how it varied in the past, and how it has influenced the landscape of both the local environment and greater California.

The solid earth plays a major role in the long-term geologic carbon cycle. Atmospheric, oceanic, and mantle derived CO2 or CO2-rich fluids reacts with silicate minerals and/or dissolved cations in the lithosphere to form secondary carbonate minerals in a variety of geological environments (regional metamorphism, contact metamorphism, subduction zone metamorphism, hydrothermal and ore-forming systems in the continental and oceanic crust, sedimentary basins, and weathering). The net rate, timescales, and fluxes of CO2 into secondary carbonates via these carbonation reactions thus exerts a first order control on the global carbon cycle balance, and serves as a monitor of broader chemical transport via fluid flow and related tectonic processes within these diverse lithospheric contexts. In order to interrogate and quantify these matters of rate, timing, and flux of CO2 (and hydrothermal fluid flow in general) within the lithosphere over geologic (i.e. >1 Myrs) timescales, an accurate and precise carbonate geochronometer is required.

Carbonate geochronology has proven to be a significant challenge due to natural complexities and analytical limitations. This study is focused on improving our ability to directly measure the timing of carbonate mineralization by refining and validating both the U/Pb and Sm/Nd carbonate geochronometers. Its developmental emphasis will be on the less-frequently tested Sm/Nd system for carbonates, and on the subsequent integration and cross-checking of Sm/Nd and U/Pb data. This development will take advantage of new analytical and sample preparation techniques that have already been developed at BU and elsewhere. Preliminary data suggest that carbonate minerals datable by Sm/Nd do exist, though the exact context and identity of the datable mineral?s occurrence is not clear. The team will seek to refine carbonate geochronology by, 1) careful sample characterization to identify the exact minerals that are ultimately being dated as well as their geological occurrence, 2) refining sample preparation methods to separate and extract datable co-genetic phases for precise Sm/Nd and U/Pb geochronological analysis, 3) establish protocols for testing the accuracy of carbonate geochronology. Three field contexts of carbonate mineralization will be explored including 1) regional metamorphic carbonate, 2) hydrothermal carbonate associated with sulfide/sulfate or ore forming systems, and 3) modern carbonates forming at hot springs and on the sea floor.

This project will provide new tools that solid-earth geoscientists can use to 1) explore, quantify, and illuminate the role of the solid-earth in the global geological carbon cycle, and 2) explore the rate, timing, and flux of fluid flow and associated chemical transport and tectonic processes in the lithosphere in general. Through undergraduate coursework and high school outreach programs in place at BU and Stanford, students will be educated as to the relevance of the solid earth in broader geoscience issues including carbon management, climate, and earth evolution. The project will bring together two geochemists with complementary tools and interests and will contribute to the establishment of new lab infrastructure at Stanford for an early career PI. The BU graduate student who will drive this research will contribute to work in both the BU and Stanford labs.

The chemical weathering of minerals moderates the concentration of carbon dioxide in the atmosphere, the supply of key nutrients to terrestrial and aquatic ecosystems and the release of naturally occurring contaminants. As such, chemical weathering is a critical component of the Earth system. The movement of water through soils and hillslopes is an important control on overall chemical weathering rates, and the resulting connection between the movement of water and chemical reactions in the subsurface is thus critical for understanding not only Earth's history, but also how Earth's systems will respond to future climatic and anthropogenic changes. However, current models cannot predict the observed export of dissolved solutes from landscapes. To address this problem, this project will use a combination of field studies and reactive transport modeling approaches to determine (1) how the competition between the rates of chemical reactions and solute transport dictates concentration-discharge relationships in rivers and the resulting chemical fluxes, (2) the consequences of weathering reactions and fluid mixing on the stable and radiogenic isotopic composition of waters, and (3) the operation of a 'hydrologic thermostat' that governs global scale chemical weathering rates, and by extension atmospheric carbon dioxide levels, over geologic timescales. Evaluation of the latter is an overarching goal of this project that has the potential to provide new information about the mechanism underlying one of the most profound features of Earth's history: its long-term temperature stability. Students from diverse backgrounds and across different levels will benefit from the exposure to field measurement, data synthesis and numerical modeling during the course of the project.

The reactive transport approach is powerful tool for understanding the chemical evolution of Earth's environments. Nevertheless, there are very few opportunities for professional training in this area at or beyond the graduate school level, although reactive transport approaches are widely used in both industry and research. A major educational goal of this project is to build a solid conceptual understanding of reactive transport approaches and models by offering a yearly short-course on reactive transport at Stanford University for graduate students, postdoctoral fellows and faculty from a broad spectrum of U.S. institutions. The course will serve as an introduction to key reactive transport concepts and their application to biogeochemical systems, and will thus provide an entry point into the field and access to a growing community of people that use and develop these models. Each year the course will include several instructors and provide an opportunity for participants to discuss their research and receive feedback and recommendations. The research proposed here will also be featured as examples, and the graduate students from my research group will play key roles in continuing to develop and improve the course, gaining experience as instructors that will carry over into their future careers.

The likelihood of an earthquake to occur at a specific place and time depends on a number of parameters that are difficult to constrain. For example, short-term estimates of strain rates that exceed longer-term fault slip rates are one parameter that we consider to increase the risk for near-future release of accumulating strain. At many active plate boundaries, there is a general agreement between modern and the long-term geological constraints on crustal deformation rates. However, in the Eastern California Shear Zone (ECSZ), southern California, the geological estimations are half of those suggested by the geodetic data. Notwithstanding, the long-term geological record of fault-slip rates is based on a collection of palaeoseismological data from the past 50,000 years, which compared to the approximately 20 Ma of fault activity in the ECSZ can only offer a very partial understanding of long-term faulting processes. This study will combine microstructural analysis, isotopic and geochemical constraints, and advanced in situ absolute (SHRIMP-RG) dating techniques to study the timing and formation mechanisms of syn-tectonic opal precipitates from the ECSZ, with the aim of developing a new approach for directly dating fault activity, and to ultimately establish a long-term record of fault activity. Specifically, this project will seek to determine (1) the fluid source and formation mechanisms of fault-related opals; (2) the timing of opal precipitation and the temporal association with brittle deformation events (e.g., syn-tectonic/post-tectonic). Outcomes of this project include the development of a new approach for (1) direct dating of paleo-earthquakes using in situ SHRIMP-RG Th/U and U-Pb dating techniques applied to fault-related material; (2) dating fault activity from initiation (millions of years) to present time. Important anticipated outcomes from this case study on the Mojave Desert segment of the ECSZ include long-term constraints on the timing of initiation and history of fault activity that will help to resolve discrepancies between estimated long- and short-term strain accumulation rates.

Given the recent and devastating earthquakes, there is a growing public concern that high-magnitude earthquakes are more frequent today than in the past, along with a demand for more accurate prediction. Thus, a major goal of this project is to provide up-to-date palaeoseismological data to both the scientific community and the general public. This project will develop a new high-spatial resolution dating techniques for fault related materials that will then be available to the scientific community through two shared analytical facilities. Data from this project will be contributed to the U.S. Geological Survey paleoseismic database.

This request is to support a workshop that aims to assess the current status of Reactive Transport Modeling (RTM) usage within the Geochemical and Biogeochemical communities, to identify barriers, and to ultimately enhance communication between the modeling and experimental and field researcher communities. Proponents will invite 20 ? 25 researchers, include leading reactive transport code developers/users and leading geochemists and biogeochemists who are interested in including RTM in their research toolbox, to participate in a 2-day workshop in Washington, DC. The complexity and capacity of (bio)geochemical and hydrologic data collection have increased substantially over the past decade, while the accessibility of interpretive tools has not. As a consequence, there is a host of key questions regarding the fundamental coupling of biological, geochemical and hydrological process that can be uniquely addressed through the application of RTM approaches. The overall goal of this workshop is therefore to identify pathways that would facilitate the expansion of RTM approaches and concurrently build a strong community of users and developers. By addressing the systemic challenges in education and identifying key technical gaps, the broader impact of the workshop is a clear roadmap to ensure the widespread expansion of powerful modeling approaches that can capitalize on the era of expansive data to address new hypotheses in (bio)geochemical sciences.

The Stanford Site of the National Nanotechnology Coordinated Infrastructure (NNCI) at Stanford University will provide open, cost-effective access to state-of-the-art nanofabrication and nanocharacterization facilities for scientists and engineers from academia, small and large companies, and government laboratories. Stanford will open the Stanford Nano Shared Facilities (SNSF), the Stanford Nanofabrication Facility (SNF), the Mineral Analysis Facility (MAF), and the Environmental Measurement Facility (EMF) more fully to external users. Open access to these facilities will not only promote the progress of science but also accelerate the commercialization of nanotechnologies that can solve a broad array of societal problems related to energy, communication, water resources, agriculture, computing, clinical medicine, and environmental remediation. Stanford will create and assemble a comprehensive online library of just-in-time educational materials that will enable users of shared nanofacilities at Stanford and elsewhere to acquire foundational knowledge independently and expeditiously before they receive personalized training from an expert staff member. Stanford staff members will also collaborate with two minority-serving institutions (California State University Los Angeles and California State University East Bay) to provide coursework, hands-on training, and nanofacility access to their students.

The Stanford Site's shared nanofacilities will offer a comprehensive array of advanced nanofabrication and nanocharacterization tools, including resources that are not routinely available, such as an MOCVD laboratory that can deposit films of GaAs or GaN, a JEOL e-beam lithography tool that can inscribe 8-nm features on 200-mm wafers, a NanoSIMS, and a unique scanning SQUID microscope that detects magnetic fields with greater sensitivity than any other instrument. The facilities occupy ~30,000 ft2 of space, including 16,000 ft2 of cleanrooms, 6,000 ft2 of which meet stringent specifications on the control of vibration, acoustics, light, cleanliness, and electromagnetic interference. The staff members who will support external users have acquired specialized expertise in fabricating photonic crystals, lasers, photodetectors, optical MEMS, inertial sensors, optical biosensors, electronic biosensors, cantilever probles, nano-FETs, new memories, batteries, and photovoltaics. Stanford will endeavor to increase the number of users from non-traditional fields of nanoscience (e.g., life science, medicine, and earth and environmental science) by creating a targeted formal curriculum, fabricating experimental nanostructures as a service, providing seed grants, and leading seminars and webinars.

This project will host the 2017 AGU-SEG Hydrogeophysics conference that will be coorganized
by the Society for Exploration Geophysicists (SEG) and the American Geophysical Union (AGU). The meeting will be held at Stanford University July 24-27, 2017 and will focus on geophysics as a tool in critical zone science. The Critical Zone is the region of Earth from that reaches from the top of the vegetation down through the soil, weathered rock, and fractured bedrock to the base of the water table. Near surface geophysical methods have been used to image shallow root zones, quantify the architecture and depth of the Critical Zone, determine subsurface water content and the depth to the water table, measure groundwater/surface water interactions, and measure gas exchange between soils and the atmosphere.

Despite the utility of using geophysical methods to address Critical Zone, there are minimal studies in which geophysical measurements are fully integrated within scientific studies of the Critical Zone.
The conference goals are to: (1) Bring together and foster multidisciplinary collaborations between a diverse set of Critical Zone scientists and near surface geophysicists. (2) Identify areas in Critical Zone science where near surface geophysics is under-utilized. (3) Identify future research focus/funding areas for Critical Zone geophysics. (4)Produce a white paper highlighting future research opportunities. The organizing committee for the workshop consists of members from the communities of researchers engaged in near surface geophysics, hydrogeophysics and Critical Zone science and includes a broad range of career stages.

Satellite or airborne mapping, or remote sensing, of soil nutrient and contaminant levels would have wide benefits for forest and rangeland management, carbon budget allocation, water quality, and agricultural systems. The central challenge in the use of remote sensing to infer soil quality is that most soils are covered by vegetation, which shields the soil from direct observation. The goal of this project is to develop new methods that use the chemical and physical characteristics of vegetation that can be mapped using remote sensing techniques to determine the quality of underlying soil. The benefit of using remote sensing techniques to quantify soil properties is two-fold: (1) remote sensing techniques uniquely provide information at the scale of management, for example a watershed or national forest, and (2) allow for repeat and ultimately real-time detection of changing environmental conditions, including drought, nutrient limitation, changing plant species distribution, contamination, climatic change, and disease.

This project seeks to decode the chemical signals in soils using the reflectance of the overlying vegetation, as measured by the National Ecological Observatory Network's (NEON) Airborne Observation Platform (AOP). The AOP collects 1 m reflectance data using a visible to shortwave infrared (VSWIR) sensor, as well as Light Detection and Ranging (LiDAR) data. To build a relationship between NEON imaging spectroscopy data and the underlying soil characteristics, the research team will analyze a sample archive of paired vegetation and soil and sediment samples from over 400 sites successfully collected in conjunction with the AOP survey in June of 2018. The dataset spans more than 300 km2 in the Upper East River watershed in Colorado, encompassing four headwater catchments with variable geology and topography, including two metals-impacted watersheds and diverse land-use practices. A number of complementary projects will also use the dataset to characterize microbial communities, bare rock mineralogy, and plant species distributions. Here, the airborne reflectance data, when paired with the ground sampling campaign, will be used to test for relationships between vegetation and soil properties and to extrapolate these relationships across a large spatial domain. Our overarching objective is to develop an approach to characterize soil carbon, nutrients and metal contaminants in a spatially explicit way. Ultimately, establishing the utility of next-generation sensors for mapping biogeochemical processes, at the scale of management, is a critical step in the evolution from airborne-based regional datasets to satellite missions with global, repeat coverage, including NASA's Hyperspectral Infrared Imager(HyspIRI) mission and Germany's Environmental Mapping and Analysis Programme (EnMAP). This project is jointly funded by the Division of Earth Sciences and the Ecosystem Science Cluster in the Division of Environmental Biology.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Across the physical sciences, many systems manifest as the result of a coupled and codependent set of chemical, mechanical and biological processes which are too complex to be solved without the assistance of numerical modeling techniques. Now more than ever, the accurate prediction of physiochemical processes such as those dictating the health of soil, the growth of crops and the quality of water is paramount to sustaining our increasing global population. Fortunately, modern advancements in computational capability are extraordinary, and recent transitions to more open-source computing platforms mean that the next decade of research will develop, employ and evaluate models faster than ever before. Thus, enhancing model literacy across all career stages is critical. Such training may indeed stand as a critical limiting step in our ability to harness the latest technological advances to address societally relevant problems, ranging from resource sustainability to the discovery of new materials. The present RCN will use the geosciences as a test bed for developing a framework for open-loop learning: the idea that education can and should be a continuous process rather than the result of having attended a University or a topical short course. In order to support a continuous educational platform for the use, development and stewardship of models, proponents will create a novel, open framework consisting of Modeling Abilities and Rubrics (MAR). The abilities and the associated rubrics will allow individuals to match and leverage resources afforded by their home institutions, those available through on-line learning and those provided by community efforts, to strengthen and expand their particular skill set and knowledge level. In addition to accelerating the adoption and use of geoscience models, the platform proponents will create can be widely generalized by other communities in the physical sciences that rely on numerical models and the associated scientific workflows to foster model literacy.

Numerical Reactive Transport Models (RTMs) have become a key tool for advancing knowledge across a broad swath of the geosciences, from early diagenesis and continental weathering to contaminant fate and transport and nuclear waste storage. However, the early developers of such software have been few in comparison to the broad variety of applications and interested users, such that educational opportunities for students are unfortunately rare. This disparity also means that it is difficult for the existing community of users to stay abreast of the rapid advances in both computational approaches and workflows. To address these needs, the objective of this project is to develop a community-based educational model to enable the geoscience community to embed Reactive Transport Models (RTMs) in their scientific and educational workflows. This effort spans universities and national laboratories, all of whom are motivated to develop an integrated training platform to address a growing gap between model capabilities and the user base who can apply them. To accomplish this, proponents will serve as a platform for training and as a repository and community resource for new advancements in model frameworks. This will be accomplished through a series of activities: (1) development of an RTM-Hub that will collect and meaningfully organize materials and opportunities and present an abilities-based pedagogical framework to support an open-loop educational model, (2) development of a novel framework outlining the Modeling Abilities and Rubrics (MAR) to serve as a roadmap for personalized education, (3) enhance the educational infrastructure by leveraging existing and newly developed on-line materials, as well as a curriculum that is common across most universities, and (4) organize and foster a self-sustaining summer RTM Institute. This RCN proposal is specifically intended to change the user-software landscape by creating a community-based and flexible education framework that is designed to enable to grow the educational platform beyond what one could otherwise achieve individually, or even as a community.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Non-Technical Description:
The National Nanotechnology Coordinated Infrastructure site at Stanford University, nano@stanford, promotes nanoscience and engineering by making experimental resources and the know-how to use them available to all. At the core of nano@stanford are four advanced research facilities that are open for use by any researcher, from other universities, industry, or government: the Stanford Nano Shared Facilities (SNSF), the Stanford Nanofabrication Facility (SNF), the Stanford Microchemical Analysis Facility (MAF), and the Stanford Isotope and Geochemical Measurement and Analysis Facility (SIGMA). These facilities are staffed with technical experts dedicated to supporting the progress of science and together span the full range of fabrication and characterization methods to serve the broad user community. The site welcomes all disciplines; researchers use the facilities to solve real world problems in energy, environment, medicine, and beyond. The site also hosts artists and teachers, as its mission is to train and educate, not only the researchers in the facilities, but anyone anywhere wanting to learn about experimental nanoscience and technology. nano@stanford cultivates a library of just-in-time educational materials aimed at building foundational knowledge for the newest researchers and is available to everyone everywhere. nano@stanford has developed and will expand programs in workforce development, teacher training, and K-12 outreach. Through its partners in the NNCI network, nano@stanford will continue to expand these efforts to educate beyond the classroom and beyond the lab.

Technical Description:
nano@stanford offers a comprehensive array of nanofabrication and nanocharacterization equipment and expertise, housed in facilities that encompass ~30,000 ft2 of lab space, including 16,000 ft2 of cleanrooms, 6,000 ft2 of which is low vibration. Fabrication capabilities are anchored by a full electronics device fabrication cleanroom and a nanopatterning laboratory that are supplemented by a dozen lab spaces providing specialized and flexible processing systems. Characterization capabilities encompass the full suite of tools for imaging and chemical/physical property identification of materials. nano@stanford offers advanced capabilities not normally available to the research community at large. These specialized capabilities include: MOCVD for growing crystalline films of III-V materials; Electron-Beam Lithography for wafers up to 200 mm; NanoSIMS for isotope analysis at high lateral resolution; scanning SQUID for high resolution mapping of surface magnetic fields. Experienced, technical staff support all researchers, who have used the facilities to develop and characterize advanced structures, such as photonic crystals, photodetectors, optical MEMS, inertial sensors, optical/electronic biosensors, cantilever probes, nano-FETs, new memories, batteries, and photovoltaics. nano@stanford welcomes researchers in non-traditional areas of science and engineering, such as the life sciences and medicine, earth and environmental sciences, and offers personal consultations, seed grants, fabrication and characterization services, seminars and webinars, to the nano-curious.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Nitrogen pollution is a Grand Challenge identified by the National Academies. Fertilizer production has outpaced removal of nitrogen from wastewater, leading to continuous losses that threaten aquatic ecosystems and human health. This project aims to meet this challenge by recycling waterborne nitrogen pollutants into high-purity ammonia. The PIs’ approach is unique in its ability to reduce nitrogen emissions and their negative cascade effects; reduce the energy and costs of conventional fertilizer production and wastewater treatment; and address legacy pollution that can persist for decades in coastal ecosystems like the Gulf of Mexico. The overall goal of this EFRI Distributed Chemical Manufacturing research project is to understand, design, and control multifunctional electrochemical processes that enable on-site fertilizer manufacturing and water purification with minimal environmental impacts. The project combines fundamental breakthroughs in novel materials and processes to convert wastewater pollutants into products. The project includes integration of the fundamental discoveries with cost optimization and performance in various wastewaters, as well as prioritizing adoption locations and value propositions for recovery facilities. Because re-engineering the nitrogen cycle is a demanding challenge, it requires the best approaches from the entire U.S. talent pool. Thus, the project team plans to broaden participation by hosting an annual workshop and demonstration day at a Stanford pilot-scale water treatment plant and invite underrepresented K-12 students; local community members; undergraduate researchers; and the project’s industrial advisory board representing fertilizer production, agriculture, and water treatment. The team will also develop workshops for incoming underrepresented undergraduate students, hands-on lab activities in classes, nitrogen-focused modules with K-12 students, and mentored research experiences for high school and undergraduate EFRI Scholars.

Current engineering efforts to rebalance the nitrogen cycle have largely concentrated on the improvement of the Haber-Bosch process to produce ammonia or expansion of nitrogen removal from wastewater. This project puts forward a transformative vision: recycling reactive nitrogen (e.g., ammonia, nitrate) in distributed nitrogen refineries that convert fugitive emissions in waste waters into high-purity ammonia. The overall goal of the research is to understand, design, and control multifunctional electrochemical unit processes that enable distributed ammonia manufacturing and water purification with minimal environmental impacts. The project will utilize electrodialysis and nitrate reduction as a platform to benchmark and characterize ammonia-selective catalysts, as well as a treatment process applicable to two ubiquitous wastewaters: municipal wastewater and fertilizer runoff. The project’s objectives are to: (1) understand and control electrocatalytic microenvironments via selective electrochemical reactive separations; (2) establish quantitative material and process innovation targets for energy-efficient, cost-effective, and adaptive processes; and (3) leverage economic and environmental assessments to prioritize local contexts and products for wastewater-derived ammonia manufacturing.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.