Ravi Kukkadapu

Fe-Mössbauer Spectroscopic Studies of Fe containing Materials

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Ravi Kukkadapu

Fe compounds play a critical role in soil organic matter transformation, in removal of metal contaminates from soils, in redox chemistry of catalysts, etc. Identification of the Fe species by…

Microbiological, Geochemical and Hydrologic Processes Controlling Uranium Mobility: An
Integrated Field-Scale Subsurface Research Challenge Site at Rifle, Colorado

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Ravi Kukkadapu

Project type

Large-Scale EMSL Research

The U.S. DOE faces the challenge of cleaning up and/or monitoring large, dilute plumes contaminated by metals, such as U, Tc and Cr, whose mobility and solubility change with redox status. At the…

Biogeochemical transformation of soil Fe- and Mn- mineral phases along a redox gradient: Implications for C sequestration

Lead Institution

University of Delaware

Principal Investigator

Donald Sparks

Project type

Large-Scale EMSL Research

Iron (Fe) and manganese (Mn) oxides, hydroxides and oxyhydroxides are well known redox-sensitive mineral components of environmental systems. Iron minerals in soils and sediments occur in a variety…

Stability of Organic Matter-Clay Systems in Presence of Aqueous Fe(II)

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Ravi Kukkadapu

Stabilization of soil organic matter (SOM) is important to sequestrate carbon and mitigate greenhouse gas emissions. The factors that govern this stabilization and preservation of OM, under redox…

Reduction of Technetium by Fe(II) associated with reduced clay mineral nontronite

Lead Institution

Miami University

Principal Investigator

Hailiang Dong

Project type

Large-Scale EMSL Research

Because clay and clay-like minerals are commonly present at DOE sites (smectite, illite, chlorite, biotite), and they are potential backfill materials for nuclear waste repositories, the interaction…

Reactivity of iron-bearing phyllosilicates with uranium and chromium through redox transitions zones

Lead Institution

Miami University

Principal Investigator

Hailiang Dong

Project type

Large-Scale EMSL Research

Iron-bearing phyllosilicate minerals are widely distributed and often account for about half of the iron in soils and sediments. They play an important role in environmental processes such as…

Transmission Mössbauer Spectroscopic Studies of Fe-containing materials

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Ravi Kukkadapu

Fe is ubiquitous in soils and sediments, and its redox chemistry plays an important role in the fate and transport of nutrients, migration/attenuation of hazardous compounds, and dynamics of soil…

Microscale and spectroscopic investigations in geochemical and microbiological systems

Lead Institution

Pacific Northwest National Laboratory

Principal Investigator

John Zachara

Project type

Large-Scale EMSL Research

Apply experimental manipulation and field investigations to understanding the behavior of selected chemical and microbial components in natural systems. The research is targeted towards compounds…

Fe oxide and organic carbon interactions: implications for global carbon sequestration

Lead Institution

Colorado State University

Principal Investigator

Thomas Borch

Project type

Large-Scale EMSL Research

Iron (Fe) minerals can have large specific surface areas and reactive functional groups, which make them strong sorbents for soil nutrients, contaminants, and organic matter (OM), therefore,…

Proteomic view of the iron deficiency response in Dunaliella

Lead Institution

University of California, Berkeley

Principal Investigator

Sabeeha Merchant

Project type

Large-Scale EMSL Research

Algae are responsible for half of global primary productivity and have an important role in biogeochemical cycling. Algae can thrive in nutrient-rich and nutrient-depleted environments, indicating…

Experimental and Theoretical Studies of Reaction Pathways for the Breakdown of Chlorinated Hydrocarbon Molecules by Metal and Metal Oxide Nanoparticles(including PNNL Scope # 42184/44076, Baer/Amonette/Tratnyek Nano-Fe BES/EMSP project)

Lead Institution

Pacific Northwest National Laboratory

Principal Investigator

James Amonette

Project type

Large-Scale EMSL Research

Metal and metal-oxide nanoparticles have been shown to have high reactivity towards a variety of chemical species, including chlorinated hydrocarbons and reducible oxyanions that frequently…

Interactions Between Fe(III) - Reducing Bacteria and Fe Oxides: Microbial and Geochemical Dissolution Controls (Zachara BES-oxide), PNNL Scope #28036)

Lead Institution

Pacific Northwest National Laboratory

Principal Investigator

John Zachara

Project type

Exploratory Research

Investigate electron transfer mechanisms involved in bacterial Fe(III) oxide reduction. Work authorization text added 08/11/05: Fe(III) oxides poise the oxidation/reduction potential of…

The role of phyllosilicate minerals in mediating the temperature sensitivity of enzymatic activity in soil organic matter transformations

Lead Institution

Oregon State University

Principal Investigator

Markus Kleber

Project type

Large-Scale EMSL Research

The underlying idea of this proposal is the assumption that temperature sensitivity in multiple component systems can be expressed by a non-linear combination of two component systems. Our main…

Characterization of Mercury Reduction by Fe(II) Minerals

Lead Institution

Rutgers University

Principal Investigator

Nathan Yee

Project type

Large-Scale EMSL Research

Mercury is a key contaminant of concern found in Department of Energy sites. Because the chemical form of Hg strongly affects its toxicity and subsurface transport, there is significant interest in…

Coupling of Fe and Tc Speciation in Subsurface Sediments: Implications to Long-Term Tc Immobilization (Zachara NABIR-Fe/Tc, PNNL Scope # 40761)

Lead Institution

Pacific Northwest National Laboratory

Principal Investigator

John Zachara

Project type

Exploratory Research

Creating an in-situ bio-barrier containing sediment-bound, biogenic FE(II) to reduce and collect mobile Tc(VII)O4 - The research objective is to provide scientific insights on the rates of reductive…

Structure and Chemical Mapping of Soil Organic Matter on Mineral Surfaces

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Ravi Kukkadapu

Secreted and decomposing soil organic matter (SOM) containing carbon, nitrogen, phosphorus, and metals form the basis of many bio/organic matter-mineral interactions in soils. These compounds are …

Biogeochemical Processes Responsible for the Enhanced Transport of Plutonium under Transient Unsaturated Condtions.

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Ravi Kukkadapu

Project type

Large-Scale EMSL Research

Plutonium is an element of concern because of its radiotoxicity. At Savannah River Site (SRS), as a result of processing Pu for nuclear weapons, some ~60 Ci of 238Pu and 239Pu was released into…

Remediation & Closure Science Project/ Subsurface Science Tasks (Zachara/Freshly, EM-closure, PNNL Scope #47040). [was aka S & T Road Mapping for Needs From All Sources (PNNL Scope #30998)].

Lead Institution

Pacific Northwest National Laboratory

Principal Investigator

John Zachara

Project type

Exploratory Research

Hanford Remediation and Closure Science Project The Hanford Site Groundwater Protection Program, formerly the Groundwater/ Vadose Zone Integration Project, was established in 1997 to develop the…

The mechanism of pyrite formation: Implications for metal mobility during iron-sulfide transformations

Lead Institution

University of California, Riverside

Principal Investigator

Timothy Lyons

Project type

Large-Scale EMSL Research

Sulfidic sediments are a key sink for many potentially toxic trace elements in marine settings, with much of these elements ultimately being concentrated into the mineral pyrite. Pyrite can be an…

Grand Challenge in Biogeochemistry

Lead Institution

Pacific Northwest National Laboratory

Principal Investigator

James Fredrickson

Project type

Grand Challenge

Do multiheme cytochromes associated with the outer membrane of metal reducing bacteria (mtrC in Shewanella oneidensis and omcB in Geobacter sulfurreducens, for example) transfer electrons to Fe(III)…

Microbial Reduction of Iron in Sedimentary Clays:
Implications for Subsurface Microbial Ecology and Bioremediation

Lead Institution

Miami University

Principal Investigator

Hailiang Dong

Project type

Exploratory Research

Past studies have shown that certain subsurface bacteria are capable of utilizing oxidized forms of metals as electron acceptors, coupled with oxidation of organic matter. Most studies have focused…

The Role of Microenvironments and Physicochemical Subsurface Components on Field Scale Biogeochemistry and Contaminant Mobility

Lead Institution

Pacific Northwest National Laboratory

Principal Investigator

James McKinley

Project type

Exploratory Research

This is a renewal proposal for a previous collaborative effort between the PNNL Scientific Focus Area (SFA) and EMSL. The research proposed will resolve critical Hanford and basic subsurface science…

Extracellular Research Thrust for EMSL SSA

Lead Institution

Pacific Northwest National Laboratory

Principal Investigator

Kirsten Hofmockel

This project will develop a conceptual framework that defines the biotic and abiotic mechanisms regulating the persistence of mineral associated organic matter (OM). The specific goals are to…

Characterization of novel arsenic-iron precipitates formed during biological iron reduction

Lead Institution

Colorado State University

Principal Investigator

Thomas Borch

Project type

Exploratory Research

Arsenic (As) is a priority pollutant, the fate of which is in part controlled by reactions with ferrous iron. Ferrous iron is capable of mediating solid phase transformations of soil and sediment…

Nanoscale Investigation of Microbial Role in Promoting the Smectite to Illite Transformation

Lead Institution

Miami University

Principal Investigator

Hailiang Dong

Project type

Exploratory Research

Smectite-illite interstratified clay minerals are ubiquitous in sedimentary basins. The smectite to illite transformation is linked to the maturation, migration and trapping of hydrocarbons, the…

Role of Microenvironments and Transition Zones in Subsurface Reactive Contaminant Transport

Lead Institution

Pacific Northwest National Laboratory

Principal Investigator

James McKinley

This is a renewal proposal for a previous collaborative effort between the PNNL Scientific Focus Area (SFA) and EMSL. The research proposed will resolve critical Hanford and basic subsurface science…

Fe-Mössbauer Spectroscopic Studies of Fe containing Materials

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Ravi Kukkadapu

Fe compounds play a critical role in soil organic matter transformation, in removal of metal contaminates from soils, in redox chemistry of catalysts, etc. Identification of the Fe species by…

Non-stoichiometric precipitation of phase-pure hydrotalcite-like compounds

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Ravi Kukkadapu

Project type

Exploratory Research

Hydrotalcite-like compounds (HTLCs), brucite-like materials, are used as gaseous adsorbents (e.g., CO2, NOx, SOx, etc.), anion exchangers, catalyst precursors, and catalyst supports. The general…

57Fe-Mossbauer studies of sediment cores from Integrated Field-Scale Subsurface Research Challenge Site at Rifle, Colorado

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Ravi Kukkadapu

The U.S. DOE faces the challenge of cleaning up and/or monitoring large, dilute plumes contaminated by metals, such as U, Tc, Pu, Hg, Cr, etc, whose mobility and solubility change with aquifer redox…

The Role of Interfacial Water on Mineral Transformations in Wet Supercritical CO2

Lead Institution

Washington State University

Principal Investigator

Andrew Felmy

Project type

Large-Scale EMSL Research

We propose a comprehensive experimental and theoretical investigation of the molecular mechanisms governing the role of interfacial water in the reactivity of mineral phases in supercritical carbon…

Using Multi-Modal Micro-Spectroscopy Techniques to Determine the Impact of Aerosolized Organic Material on Biogeochemical Cycles of Fe and P in the Amazon Basin

Lead Institution

University of Miami

Principal Investigator

Cassandra Gaston

Project type

Large-Scale EMSL Research

Aerosols transported from Africa are thought to critically impact the biogeochemical cycling of iron (Fe) and phosphorus (P) in the Amazon and relieve nutrient limitations in this ecosystem…

Couple proton-electon dynamics in iron-containing phyllosilicates: annite, KFe3AlSi2O10(OH)2 - Mössbauer determination of Fe2+/Fe3+ ratio (N.Hess LDRD, PNNL SCOPE # 90001)

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Nancy Hess

Project type

Exploratory Research

The focus of this investigation is coupled proton-electron dynamics in geochemical systems, specifically the redox reactions in annite, an iron-rich hydrous phyllosilicate. This topic is of…

Role of Microenvironments and Transition Zones in Subsurface Reactive Contaminant Transport

Lead Institution

Pacific Northwest National Laboratory

Principal Investigator

James McKinley

Project type

Exploratory Research

The PNNL Scientific Focus Area (SFA) will resolve critical Hanford and basic subsurface science issues through integrated, multi-disciplinary, science-theme focused research on the role of…

Role of Microenvironments and Transition Zones in Subsurface Reactive Contaminant Transport

Lead Institution

Pacific Northwest National Laboratory

Principal Investigator

James McKinley

This is a renewal proposal for a previous collaborative effort between the PNNL Scientific Focus Area (SFA) and EMSL. The research proposed will resolve critical Hanford and basic subsurface science…

Quantification and Chemical Analysis of Iron Oxidation in Microbially-Reduced Sediments

Lead Institution

Villanova University

Principal Investigator

John Komlos

Project type

Exploratory Research

The microbial reduction of iron has been shown to be an important process in the transformation and remediation of contaminated sediments. Subsequent reoxidation of microbially-reduced iron has…

SEM of Soil Goethites

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Ravi Kukkadapu

Project type

Exploratory Research

SEM of soil enriched with Al-goethites before and after microbial reduction.

Role of Surface and Interface on Transport Properties in Nanoscale Conducting Oxides

Lead Institution

University of South Carolina

Principal Investigator

Xiao-dong Zhou

Project type

Large-Scale EMSL Research

Size-dependent (~50 nm) chemical and physical properties of electronic materials have been attributed to primarily either intrinsic contributions, such as changes in the lattice energy and discrete…

Use of EMSL Mossbauer Spectroscopy Facility to support National Security Division's (NSD) Actinide Mossbauer Spectroscopy project

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Ravi Kukkadapu

The purpose of this study is to develop actinide Mossbauer spectroscopy facility at PNNL. The project is part of NSD's "Ultra-Sensitive Nuclear Measurements" initiative, FYI13 LDRD. …

Software Development for High-Resolution Mass Spectrometry Analysis of Small Molecules: Enabling High-Throughput, Reproducible Data Processing and Annotation.

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Yuri Eberlim de Corilo

Modern high-resolution mass spectrometry has dramatically increased the volume (distinct analytical techniques and polarity modes) and quality (higher resolving power, dynamic range, mass error…

Mössbauer Analysis of Microbial Redox Transformations of Naturally Occurring Fe(III)-bearing Phyllosilicates

Lead Institution

University of Wisconsin, Madison

Principal Investigator

Evgenya Shelobolina

Project type

Large-Scale EMSL Research

The abundance of ferric iron in sedimentary environments and its ability to accept and donate electrons makes it important electron acceptor for microbial metabolism. Fe(III) in the structure of…

The Role of Interfacial Processes on Mineral Transformations in Wet Supercritical CO2

Lead Institution

Washington State University

Principal Investigator

Andrew Felmy

Project type

Large-Scale EMSL Research

We propose a comprehensive experimental and theoretical investigation of the role of interfacial water and CO2 on the energies, mechanisms, and rates of reactivity of a series of orthosilicate and…

Size-dependent molecular-level characterization of secondary organic aerosol from various oxidants using nanospray desorption electrospray (nano-DESI) high-resolution mass spectrometry

Lead Institution

Reed College

Principal Investigator

Juliane Fry

Project type

Large-Scale EMSL Research

Secondary organic aerosol (SOA) formation from oxidation of biogenic volatile organic compounds (BVOCs) contributes a large fraction of global aerosol loading, affecting regional and global climate. …

Mineralogy exerts control on organic molecules zonal structuring and reordering

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Odeta Qafoku

Organic C preservation in soil environments is predominantly driven by organic matter: soil mineral interactions. Yet, mechanistic uncertainties remain, namely how spatial variation in mineralogy…

Mossbauer and XPS Characterization of Fe-Based Fischer-Tropsch Catalysts

Lead Institution

Research Triangle Institute

Principal Investigator

Velu Subramani

Project type

Exploratory Research

This proposal seeks to characterize fresh and used Fe-based Fischer-Tropsch synthesis (FTS) catalysts prepared at the Research Triangle Institute (RTI) using combined Mossbauer and X-ray…

Abiotic Reduction of U(VI) by Sorbed Fe(II) and the Implications for Field-Scale Bioremediation at the Rifle IFRC Project Site

Lead Institution

Lawrence Berkeley National Laboratory

Principal Investigator

Patricia Fox

Project type

Large-Scale EMSL Research

Uranium (U) contamination of aquifers is a problem at a number of DOE sites, and bioremediation is currently being investigated at the Integrated Field Research Challenge Site at Rifle, CO as a…

Is the mobilization of sedimentary phosphorus a key player for sustaining eutrophication in the Chesapeake Bay?

Lead Institution

University of Delaware

Principal Investigator

Deb Jaisi

Project type

Large-Scale EMSL Research

With the rise of coastal dead zones, oxygen-dependent feedback effects on phosphorus (P) cycling in coastal environments will play more important roles globally. Proposed research will employ…

Integrating mineral-associated organic matter (MAOM) colloid characteristics into dissolved organic matter (DOM) representation in Earth system models

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Ravi Kukkadapu

We propose developing a workflow to generate colloids from operationally defined DOM solutions using aerosol-based techniques, then develop a spectroscopic/microscopic capability pipeline to…

Mossbauer and XPS Characterization of Fe-Based Fischer-Tropsch Catalysts

Lead Institution

Research Triangle Institute

Principal Investigator

Velu Subramani

Project type

Large-Scale EMSL Research

This proposal seeks to characterize fresh and used Fe-based Fischer-Tropsch synthesis (FTS) catalysts prepared at the Research Triangle Institute (RTI) using combined Mossbauer and X-ray…

57Fe-Mossbauer studies of sediment cores from Integrated Field-Scale Subsurface Research Challenge Site at Rifle, Colorado

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Ravi Kukkadapu

The U.S. DOE faces the challenge of cleaning up and/or monitoring large, dilute plumes contaminated by metals, such as U, Tc, Pu, Hg, Cr, etc, whose mobility and solubility change with aquifer redox…

Characterization of the bio-oil hydrotreating catalysts

Lead Institution

Environmental Molecular Sciences Laboratory

Principal Investigator

Mark Engelhard

PNNL is working on an EERE international collaboration project to exchange scientific and technical information on biomass feedstock production and conversion to biofuels with China and additionally…

Projects