A5049639810- Radioactive element chemistry and processing
- Geochemistry and Geologic Mapping
- Urban Stormwater Management Solutions
- Water Systems and Optimization
- Heavy metals in environment
- Arsenic contamination and mitigation
- Wastewater Treatment and Reuse
- Mine drainage and remediation techniques
- Water Treatment and Disinfection
- Climate Change and Health Impacts
- Air Quality and Health Impacts
- Radioactivity and Radon Measurements
- Fecal contamination and water quality
- Climate change and permafrost
- Radioactive contamination and transfer
- Advanced Photocatalysis Techniques
- Ammonia Synthesis and Nitrogen Reduction
- Environmental Science and Water Management
- Municipal Solid Waste Management
- Dendrimers and Hyperbranched Polymers
- Process Optimization and Integration
- Metal Extraction and Bioleaching
- Inhalation and Respiratory Drug Delivery
- Wastewater Treatment and Nitrogen Removal
- Biodiesel Production and Applications
University of Tennessee at Knoxville
2020-2024
Knoxville College
2024
University of California, Riverside
2020-2022
Riverside
2020
University of New Mexico
2015-2019
Wayne State University
2014
This research focused on synthesis, characterization, and application of point-of-use catalytic reactive electrochemical membranes (REMs) for electrocatalytic NO3– reduction. Deposition Pd–Cu Pd–In catalysts to the REMs produced (i.e., Pd–Cu/REM Pd–In/REM) that were active Optimal performance was achieved with a upstream counter electrode, which reduced from 1.0 mM below EPAs regulatory MCL (700 μM) in single pass through REM (residence time ∼2 s), obtaining product selectivity <2% toward...
Small interfering RNA (siRNA)-based therapies have great promise in the treatment of a number prevalent pulmonary disorders including lung cancer, asthma and cystic fibrosis. However, progress this area has been hindered due to lack carriers that can efficiently deliver siRNA epithelial cells, also challenges developing oral inhalation (OI) formulations for regional administration their lungs. In work we report ability generation four, amine-terminated poly(amidoamine) (PAMAM) dendrimer...
The chemical interactions of U and co-occurring metals in abandoned mine wastes a Native American community northeastern Arizona were investigated using spectroscopy, microscopy aqueous chemistry. concentrations (67-169 μg L(-1)) spring water samples exceed the EPA maximum contaminant limit 30 L(-1). Elevated (6,614 mg kg(-1)), V (15,814 As (40 kg(-1)) detected waste solids. Spectroscopy (XPS XANES) solid analyses identified (VI), (-I III) Fe (II, III). Linear correlations for release vs...
The objective of the current study was to investigate environmentally sustainable and energy efficient processes recover value added material from e-waste as a means divert these nondegradable materials landfills. We studied two different types plastics (1) simple mixtures like polycarbonate/polyamide (PC/PA)) found in cell phone for solvent extraction (2) complex PC/PA/acrylonitrile butadiene styrene (ABS)/poly methyl methacrylate (PMMA) many other streams pyrolysis. Solvent using...
Exposure to windblown particulate matter (PM) arising from legacy uranium (U) mine sites in the Navajo Nation may pose a human health hazard due their potentially high metal content, including U and vanadium (V). To assess toxic impact of PM derived Claim 28 (a priority mine) compared with background PM, consider putative role species V. Two representative sediment samples (Background PM) were obtained, characterized terms chemistry morphology, fractioned respirable (≤ 10 μm) fraction. Mice...
We applied spectroscopy, microscopy, diffraction, and aqueous chemistry methods to investigate the persistence of metals in water sediments from Animas River 13 days after Gold King Mine spill (August 5, 2015). The Upper watershed, located San Juan Colorado, is heavily mineralized impacted by acid mine drainage, with low pH elevated metal concentrations (108.4 ± 1.8 mg kg–1 Pb, 32.4 0.5 Cu, 729.6 5.7 Zn, 51 314.6 295.4 Fe). Phosphate nitrogen species were detected sediment samples...
The dissolution of U-bearing minerals such as coffinite (USiO<sub>4</sub>) detected in mine wastes (300 to 9000 mg kg<sup>−1</sup>U) exposed surface oxidizing conditions can cause the release U Rio Paguate, NM during hydrologic events.
The reactive transport of uranium (U) and vanadium(V) from abandoned mine wastes collected the Blue Gap/Tachee Claim-28 site in Arizona was investigated by integrating flow-through column experiments with modeling, electron microscopy. were sequentially reacted columns at pH 7.9 (10 mM HCO3-) 3.4 CH3COOH) to evaluate effect environmentally relevant conditions encountered on release U V. reaction rate constants (km) for dissolution uranyl-vanadate (U-V) minerals predominant obtained...
Upon cast iron corrosion in contact with residual disinfectants, drinking water distribution systems have become potential geogenic sources for hexavalent chromium Cr(VI) release. This study investigated mechanisms of release from scales. The oxidation the scales by disinfectant chlorine released and exhibited a three-phase kinetics behavior: an initial 2 h fast reaction phase, subsequent 2-to-12 transitional final 7-day slow phase approximately orders magnitude slower than phase. X-ray...
Abstract In this study, we explore the use of unsteady transit time distribution (TTD) theory to model solute transport in biofilters, a popular form nature‐based or “green” storm water infrastructure (GSI). TTD has potential address many unresolved challenges associated with predicting pollutant fate and through these systems, including unsteadiness balance (time‐varying inflows, outflows, storage), loading, time‐dependent reactions, scale‐up GSI networks urban catchments. From solution age...
The crystal chemistry of carnotite (prototype formula: K2(UO2)2(VO4)2·3H2O) occurring in mine wastes collected from Northeastern Arizona was investigated by integrating spectroscopy, electron microscopy, and x-ray diffraction analyses. Raman spectroscopy confirms that the uranyl vanadate phase present waste is carnotite, rather than rarer polymorph vandermeerscheite. X-ray patterns these are agreement with those reported literature for a synthetic analog. Carbon detected this identified as...
Nitrogen (N) in urban runoff is often treated with green infrastructure including biofilters. However, N fates across biofilters are insufficiently understood because prior studies emphasize low loading under laboratory conditions, or use “steady-state” flow regimes over short time scales. Here, we tested field scale biofilter during simulated storms delivering realistic transient flows high loading. Biofilter outflow ammonium (NH4+-N) was 60.7 to 92.3% lower than that of the inflow. Yet...
Permafrost thaw in warming Arctic landscapes alters hydrology and saturation-driven biogeochemical processes. Models assume that aerobic respiration occurs drained soils while saturated support methanogenesis; however, maintain redox gradients host a range of anaerobic metabolisms. We evaluated how potential redox-active solutes vary with soil moisture the active layer permafrost-affected acidic non-acidic tundra hillslopes. Oxidizing conditions persisted highly permeable organic horizons...
The world is currently dependant on fossil fuels as a fuel source for transportation and fuelling the industrial sector. increasing awareness of depletion resources environmental benefits bio-diesel has made it more attractive in recent times. Many researches are being to commercialize production. However cost major obstacle its commercialization comparison conventional diesel fuels. objective this paper produce biodiesel from Used cooking oil using two stage process acid base catalyzed...
This study investigated the reaction kinetics on oxidative transformation of lead(ii) minerals by free chlorine (HOCl) and bromine (HOBr) in drinking water distribution systems. According to chemical equilibrium predictions, carbonate minerals, cerussite PbCO3(s) hydrocerussite Pb3(CO3)2(OH)2(s), phosphate mineral, chloropyromorphite Pb5(PO4)3Cl(s) are formed systems absence presence phosphate, respectively. X-ray absorption near edge spectroscopy (XANES) data showed that at pH 7 a 10 mM...
Column experiments were conducted to study the effect of intermittent flow on mobility metals from abandoned uranium mine waste sites in Blue Gap Tachee (BGT), AZ and Laguna, NM.Intermittent represent rainfall patterns southwestern United States, involving alternate wet dry cycles.In order simulate these shorter periods 15, 30, 60, 120 360 minutes, followed by longer 24 hours, adopted for column experiments.The experiment involved sequential leaching sediments Laguna BGT with 18MΩ water (pH...