A5048743129- Groundwater and Isotope Geochemistry
- Groundwater flow and contamination studies
- Hydrology and Watershed Management Studies
- Radioactive contamination and transfer
- Radioactive element chemistry and processing
- Water Quality and Resources Studies
- Nuclear Materials and Properties
- Nuclear and radioactivity studies
- Graphite, nuclear technology, radiation studies
- Isotope Analysis in Ecology
- Ammonia Synthesis and Nitrogen Reduction
- Soil and Water Nutrient Dynamics
- Astro and Planetary Science
- Membrane Separation Technologies
- Membrane-based Ion Separation Techniques
- Atmospheric and Environmental Gas Dynamics
- Plant Water Relations and Carbon Dynamics
- Archaeology and Natural History
- Radioactivity and Radon Measurements
- Geochemistry and Geologic Mapping
- Meteorological Phenomena and Simulations
- Chemical Reactions and Isotopes
- Geology and Paleoclimatology Research
- Marine and environmental studies
- Geological and Geophysical Studies Worldwide
Lawrence Livermore National Laboratory
2015-2022
California State University, East Bay
2016
California State University, Long Beach
2015
The contamination of water resources with nitrate is a growing and significant problem. Here we report the use ultramicroporous carbon as capacitive deionization (CDI) electrode for selectively removing from an anion mixture. Through moderate activation, achieve micropore-size distribution consisting almost exclusively narrow (<1 nm) pores that are well suited adsorbing planar, weakly hydrated molecule. Cyclic voltammetry measurements reveal enhanced capacitance when compared to chloride ion...
Abstract One of the principal questions in hydrology is how and when water leaves critical zone storage as either stream flow or evapotranspiration. We investigated subsurface selection Southern Sierra Critical Zone Observatory (California, USA) within age‐ranked framework, constrained by a novel combination cosmogenic radioactive stable isotopes: tritium, sodium‐22, sulfur‐35, oxygen‐18. found significant positive correlation between tritium rate sulfur‐35 rate, indicating that age...
Capacitive deionization (CDI) is a promising water desalination technology that applicable to the treatment of low-salinity brackish waters and selective removal ionic contaminants. In this work, we show by making small change in synthetic procedure hierarchical carbon aerogel monolith (HCAM) electrodes, can adjust pore-size distribution tailor selectivity, effectively switching between adsorption calcium or sodium ions. Ion selectivity was measured for mixture 5 mM NaCl 2.5 CaCl2. For low...
This paper presents a comprehensive data-to-model workflow, including findable, accessible, interoperable, reusable (FAIR) community sorption database (newly developed LLNL Surface Complexation/Ion Exchange (L-SCIE) database) along with data fitting workflow to efficiently optimize surface complexation reaction constants multiple model (SCM) constructs. serves as universal framework mine, compile, and analyze large numbers of published well estimate for parameterizing reactive transport...
Abstract Groundwater quality is a concern in alluvial aquifers that underlie agricultural areas, such as the San Joaquin Valley of California. Shallow domestic wells (less than 150 m deep) areas are often contaminated by nitrate. Agricultural and rural nitrate sources include dairy manure, synthetic fertilizers, septic waste. Knowledge relative proportion each these contributes to concentration individual can aid future regulatory land management decisions. We show nitrogen oxygen isotopes...
Abstract Sierra Nevada forests transpire a significant amount of California's water resources, sparking interest in applying forest management to improve supply. Determining the source evapotranspiration enables managers make informed decisions. To this end, critical zone science is develop new methods work across time scales predict subsurface storage and use. In study, vegetation accessed young switched sources depending on availability, suggesting that drought vulnerability may depend...
Oxygen stable isotopes in uranium oxides processed through the nuclear fuel cycle may have potential to provide information about a material's origin and processing history. However, more thorough understanding of fractionating processes governing formation signatures real-world samples is still needed. In this study, laboratory synthesis modeled after industrial fabrication was performed follow isotope fractionation during thermal decomposition reduction ammonium diuranate (ADU). Synthesis...
The use of cosmogenically produced sulfur-35 (T1/2 = 87 days) and sodium-22 2.6 years) as intrinsic tracers can provide valuable information on catchment hydrology, flow paths, subsurface storage. A new straightforward method was created to determine the activities both 35S 22Na in various water sources by pumping large volumes (up 1000 L) through cation- anion-exchange resin columns field collect sodium sulfate ions simple chemistry lab. Samples are counted for using liquid scintillation...