Andrew R. Felmy

Washington State University

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Kevin M. Rosso

Pacific Northwest National Laboratory

Odeta Qafoku

Environmental Molecular Sciences Laboratory

P. Raics

Mizoram University

Dean A. Moore

University of Hull

Eugene S. Ilton

Pacific Northwest National Laboratory

David A. Dixon

University of Alabama

Nancy Hess

Environmental Molecular Sciences Laboratory

James R. Rustad

Office of Basic Energy Sciences

Zhe-Ming Wang

Pacific Northwest National Laboratory

Marvin J. Mason

BP (United Kingdom)

Cooperative Institutions

Pacific Northwest National Laboratory

277

Battelle

140

Environmental Molecular Sciences Laboratory

Richland College

Office of Scientific and Technical Information

National Technical Information Service

United States Department of Commerce

Washington State University

Lawrence Berkeley National Laboratory

Los Alamos National Laboratory

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Sludge Treatment Evaluation: 1992 Technical progress

L Silva Andrew R. Felmy Edwin Ding

This report documents Fiscal Year 1992 technical progress on the Sludge Treatment Evaluation Task, which is being conducted by Pacific Northwest Laboratory. The objective of this task is to develop a capability to predict the performance of pretreatment processes for mixed radioactive and hazardous waste stored at Hanford and other US Department of Energy (DOE) sites. Significant cost savings can be achieved if radionuclides and other undesirable constituents can be effectively separated from the bulk waste prior to final treatment and disposal. This work is initially focused on chemical equilibrium prediction of water washing and acid or base dissolution of Hanford single-shell tank (SST) sludges, but may also be applied to other steps in pretreatment processes or to other wastes. Although SST wastes contain many chemical species, there are relatively few constituents -- Na, Al, NO[sub 3], NO[sub 2], PO[sub 4], SO[sub 4], and F -- contained in the majority of the waste. These constituents comprise 86% and 74% of samples from B-110 and U-110 SSTS, respectively. The major radionuclides of interest (Cs, Sr, Tc, U) are present in the sludge in small molal quantities. For these constituents, and other important components that are present in small molal quantities, the specific ion-interaction terms used in the Pitzer or NRTL equations may be assumed to be zero for a first approximation. Model development can also be accelerated by considering only the acid or base conditions that apply for the key pretreatment steps. This significantly reduces the number of chemical species and chemical reactions that need to be considered. Therefore, significant progress can be made by developing all the specific ion interactions for a base model and an acid dissolution model.

Molality

Hanford Site

Base (topology)

10.2172/6642240

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Non-equilibrium thermodynamic simulation of metal uptake in the bacterial electrical double-layer

Colloids and Surfaces B Biointerfaces (2000)

Evgeny Wasserman Andrew R. Felmy Ashok Chilakapati

10.1016/s0927-7765(99)00122-8

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Citations (11)

An electrodynamics-based model for ion diffusion in microbial polysaccharides

Colloids and Surfaces B Biointerfaces (2004)

Chongxuan Liu John M. Zachara Andrew R. Felmy Yuri A. Gorby

Electrostatics

10.1016/j.colsurfb.2004.08.003

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Citations (13)

Molecular Statics Calculations of Proton Binding to Goethite Surfaces: Thermodynamic Modeling of the Surface Charging and Protonation of Goethite in Aqueous Solution

Geochimica et Cosmochimica Acta (1998)

Andrew R. Felmy James R. Rustad

Surface charge

10.1016/s0016-7037(97)00325-6

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Citations (63)

The Energetics of the Hydrogenolysis, Dehydrohalogenation, and Hydrolysis of 4,4‘-Dichloro-diphenyl-trichloroethane from ab Initio Electronic Structure Theory

The Journal of Physical Chemistry A (2004)

Eric J. Bylaska David A. Dixon Andrew R. Felmy Edoardo Aprà Theresa L. Windus

Electronic structure methods were used to calculate the aqueous reaction energies for hydrogenolysis, dehydrochlorination, and nucleophilic substitution by OH- of 4,4'-DDT. Thermochemical properties ΔHf° (298.15 K), S° (298.15 K, 1 bar), ΔGS (298.15 K, 1 bar) were calculated by using ab initio electronic structure calculations, isodesmic reactions schemes, gas-phase entropy estimates, and continuum solvation models for a series of DDT type structures (p−C6H4Cl)2−CH−CCl3, (p−C6H4Cl)2−CH−CCl2•, (p−C6H4Cl)2−CH−CHCl2, (p−C6H4Cl)2−CCCl2, (p−C6H4Cl)2−CH−CCl2OH, (p−C6H4Cl)2−CH−CCl(O), and (p−C6H4Cl)2−CH−COOH. On the basis of these thermochemical estimates, the overall aqueous reaction energetics of hydrogenolysis, dehydrochlorination, and hydrolysis of 4,4'-DDT were estimated. The results of this investigation showed that the dehydrochlorination and hydrolysis reactions have strongly favorable thermodynamics in the standard state, as well as under a wide range of pH conditions. For hydrogenolysis with the reductant aqueous Fe(II), the thermodynamics are strongly dependent on pH, and the stability region of the (p−C6H4Cl)2−CH−CCl2•(aq) species is a key to controlling the reactivity in hydrogenolysis. These results illustrate the use of ab initio electronic structure methods to identify the potentially important environmental degradation reactions by calculation of the reaction energetics of a potentially large number of organic compounds with aqueous species in natural waters.

Hydrogenolysis

Isodesmic reaction

Reactivity

10.1021/jp0312316

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Citations (12)

Characterization of radionuclide-chelating agent complexes found in low-level radioactive decontamination waste. Literature review

R. Jeffrey Serne Andrew R. Felmy Kirk J. Cantrell Kenneth M. Krupka James A. Campbell

The US Nuclear Regulatory Commission is responsible for regulating the safe land disposal of low-level radioactive wastes that may contain organic chelating agents. Such agents include ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), picolinic acid, oxalic acid, and citric acid, and can form radionuclide-chelate complexes that may enhance the migration of radionuclides from disposal sites. Data from the available literature indicate that chelates can leach from solidified decontamination wastes in moderate concentration (1--100 ppm) and can potentially complex certain radionuclides in the leachates. In general it appears that both EDTA and DTPA have the potential to mobilize radionuclides from waste disposal sites because such chelates can leach in moderate concentration, form strong radionuclide-chelate complexes, and can be recalcitrant to biodegradation. It also appears that oxalic acid and citric acid will not greatly enhance the mobility of radionuclides from waste disposal sites because these chelates do not appear to leach in high concentration, tend to form relatively weak radionuclide-chelate complexes, and can be readily biodegraded. In the case of picolinic acid, insufficient data are available on adsorption, complexation of key radionuclides (such as the actinides), and biodegradation to make definitive predictions, although the available data indicate that picolinic acid can chelate certain radionuclides in the leachates.

Oxalic Acid

Ethylenediaminetetraacetic acid

Human decontamination

Picolinic acid

10.2172/219284

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Citations (15)

Mapping the Complex Phase Formation at the Surface of Supercritical CO Reacted Fayalite for Geologic Sequestration of Greenhouse Gases

Microscopy and Microanalysis (2013)

Daniel E. Perea J. Liu Bruce W. Arey Libor Kovařík Ralph H. Colby

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.

Fayalite

10.1017/s1431927613006879

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Mica Surfaces Stabilize Pentavalent Uranium.

ChemInform (2005)

Eugene S. Ilton Anca Haiduc Christopher L. Cahill Andrew R. Felmy

Abstract For Abstract see ChemInform Abstract in Full Text.

10.1002/chin.200526011

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Citations (1)

Computation of the Electrical Double Layer Properties of Semipermeable Membranes in Multicomponent Electrolytes

Applied and Environmental Microbiology (1998)

Evgeny Wasserman Andrew R. Felmy

A methodology is presented for calculating of the surface potential, Donnan potential, and ion concentration profiles for semipermeable microbial membranes that is valid for an arbitrary electrolyte composition. This model for surface potential, Donnan potential, and charge density was applied to recently reported experimental data for gram-positive bacteria, including Bacillus brevis, Rhodococcus opacus, Rhodococcus erythropolis, and Corynebacterium species. These calculations show that previously unconsidered trace amounts of divalent and trivalent cations at very low concentrations (10(-6) M) can have significant effects on the calculated surface and Donnan potentials, at ionic strengths of I

Semipermeable membrane

10.1128/aem.64.6.2295-2300.1998

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Citations (28)

Chemical Speciation of Strontium, Americium, and Curium in High Level Waste: Predictive Modeling of Phase Partitioning During Tank Processing

Andrew R. Felmy Gregory R. Choppin David A. Dixon James A. Campbell

In this research program, Pacific Northwest National Laboratory (PNNL) and Florida State University (FSU) are investigating the speciation of strontium and americium/curium in the presence of selected organic chelating agents (ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl) aethylenediaminetriacetic acid (HEDTA), nitrilotriacetic acid (NTA), and iminodiacetic acid (IDA)) over ranges of hydroxide, carbonate, ionic strength, and competing metal ion concentrations present in high-level waste tanks. The project is composed of integrated research tasks that approach the problem of chemical speciation using macroscopic thermodynamic measurements of metal-ligand competition reactions, molecular modeling studies to identify structures or complexes of unusual stability, and mass spectrometry measurements of complex charge/mass ratio that can be applied to mixed metal-chelate systems. This fundamental information is then used to develop thermodynamic models, which allow the prediction of changes in chemical speciation and solubility that can occur in response to changes in tank processing conditions. In this way, we can develop new approaches that address fundamental problems in aqueous speciation and at the same time provide useful and practical information needed for tank processing.

Curium

Ethylenediaminetetraacetic acid

Nitrilotriacetic acid

10.2172/825789

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