Radiochemistry Annex

EMSL’s Radiochemistry Annex is designed to accelerate scientific discovery and deepen the understanding of the chemical fate and transport of radionuclides in terrestrial and subsurface ecosystems.

The annex offers experimental and computational tools uniquely suited for actinide chemistry studies. The spectroscopic and imaging instruments at this facility are ideally designed for the study of contaminated environmental materials, examination of radionuclide speciation and detection of chemical signatures. The annex houses nuclear magnetic resonance instruments and surface science capabilities, such as X-ray photoelectron spectroscopy, electron microscopy, electron microprobe, transmission electron microscopy and scanning electron microscopy. Annex users also have access to expert computational, modeling and simulation resources and support.

The annex is an environment where multiple experimental approaches are encouraged. Investigating problems at an integrated, cross-disciplinary level encourages holistic understanding, which ultimately provides policy makers the information they need to make sound remediation choices.

Like all of EMSL's capabilities, those housed in the annex are available to the scientific community at typically no cost for openly published research. Scientists gain access to instruments and collaborate with onsite microscopy experts through a peer-reviewed proposal process. Research conducted in the annex requires special information and handling. Prior to submitting a proposal, potential users should familiarize themselves with the guidance for using and shipping radioactive material to the annex.

Radiochemistry Annex videos on EMSL's YouTube channel - Learn about the individual instruments in the Radiochemistry Annex and specifically how they advance subsurface and terrestrial ecosystem science.

And don't miss the virtual tour of our Radiochemistry Annex.

Additional Information:

Instruments

Research applications Samples containing paramagnetics Soils (SOM and NOM) Metal oxide materials for catalysis applications Researchers may operate...
Custodian(s): Nancy Washton, Sarah D Burton
EMSL's Bruker wide-bore 750 MHz solids/liquids/imaging spectrometer is dedicated to radiological and environmental samples. Housed in the EMSL...
Custodian(s): Nancy Washton
The Bruker EMX electron paramagnetic resonance (EPR) spectrometer performs continuous-wave magnetic resonance using electron spins to selectively...
Custodian(s): Eric Walter
EMSL's Digital Instruments Radiological BioScope™ Atomic Force Microscope (AFM) allows radiological samples to be examined in fluids or air with...
Custodian(s): Kevin M. Rosso
Housed in EMSL's Radiochemistry Annex, the field emission electron microprobe (EMP) enables chemical analysis and imaging of radionuclides with high...
Custodian(s): Bruce Arey

Science Highlights

Posted: July 06, 2011
Scientists from Pacific Northwest National Laboratory and Rai Enviro-Chem, LLC, recently published first-ever results that illustrate the importance...

EMSL’s Radiochemistry Annex is designed to accelerate scientific discovery and deepen the understanding of the chemical fate and transport of radionuclides in terrestrial and subsurface ecosystems.

The annex offers experimental and computational tools uniquely suited for actinide chemistry studies. The spectroscopic and imaging instruments at this facility are ideally designed for the study of contaminated environmental materials, examination of radionuclide speciation and detection of chemical signatures. The annex houses nuclear magnetic resonance instruments and surface science capabilities, such as X-ray photoelectron spectroscopy, electron microscopy, electron microprobe, transmission electron microscopy and scanning electron microscopy. Annex users also have access to expert computational, modeling and simulation resources and support.

The annex is an environment where multiple experimental approaches are encouraged. Investigating problems at an integrated, cross-disciplinary level encourages holistic understanding, which ultimately provides policy makers the information they need to make sound remediation choices.

Like all of EMSL's capabilities, those housed in the annex are available to the scientific community at typically no cost for openly published research. Scientists gain access to instruments and collaborate with onsite microscopy experts through a peer-reviewed proposal process. Research conducted in the annex requires special information and handling. Prior to submitting a proposal, potential users should familiarize themselves with the guidance for using and shipping radioactive material to the annex.

Radiochemistry Annex videos on EMSL's YouTube channel - Learn about the individual instruments in the Radiochemistry Annex and specifically how they advance subsurface and terrestrial ecosystem science.

And don't miss the virtual tour of our Radiochemistry Annex.

Additional Information:

Effect of Composition and Heat Treatment on MnBi Magnetic Materials.

Abstract: 

The metallic compound MnBi is a promising rare-earth-free permanent magnet material. Compare to other rare-earth-free candidates, MnBi stands out for its high intrinsic coercivity (Hci) and its large positive temperature coefficient. Several groups have demonstrated that the Hci of MnBi compound in thin film or in powder form can exceed 12 kOe and 26 kOe at 300 K and 523 K, respectively. Such steep increase in Hci with increasing temperature is unique to MnBi. Consequently, MnBi is a highly sought-after hard phase for exchange coupling nanocomposite magnets. The reaction between Mn and Bi is peritectic, so Mn tends to precipitate out of the MnBi liquid during the solidification process. As result, the composition of the Mn-Bi alloy with the largest amount of the desired LTP (low temperature phase) MnBi and highest saturation magnetization will be over-stoichiometric and rich in Mn. The amount of additional Mn required to compensate the Mn precipitation depends on solidification rate: the faster the quench speed, the less Mn precipitates. Here we report a systematic study of the effect of composition and heat treatments on the phase contents and magnetic properties of Mn-Bi alloys. In this study, Mn-Bi alloys with 14 compositions were prepared using conventional metallurgical methods such as arc melting and vacuum heat treatment, and the obtained alloys were analyzed for compositions, crystal structures, phase content, and magnetic properties. The results show that the composition with 55 at.% Mn exhibits the highest LTP MnBi content and the highest magnetization. The sample with this composition shows >90 wt.% LTP MnBi content. Its measured saturation magnetization is 68 emu/g with 2.3 T applied field at 300 K; its coercivity is 13 kOe and its energy product is 12 MGOe at 300 K. A bulk magnet fabricated using this powder exhibits an energy product of 8.2 MGOe.

Citation: 
Cui J, JP Choi, E Polikarpov, ME Bowden, W Xie, G Li, Z Nie, N Zarkevich, MJ Kramer, and DD Johnson.2014."Effect of Composition and Heat Treatment on MnBi Magnetic Materials."Acta Materialia 79:374-381. doi:10.1016/j.actamat.2014.07.034
Authors: 
J Cui
JP Choi
E Polikarpov
ME Bowden
W Xie
G Li
Z Nie
N Zarkevich
MJ Kramer
DD Johnson
Volume: 
Issue: 
Pages: 
Publication year: 
2014

Iodine Solubility in Low-Activity Waste Borosilicate Glass at 1000 °C.

Abstract: 

The purpose of this study was to determine the solubility of iodine in a low-activity waste borosilicate glass when heated inside an evacuated and sealed fused quartz ampoule. The iodine was added to glass frit as KI in quantities of 100–24000 ppm iodine (by mass), each mixture was added to an ampoule, the ampoule was heated at 1000 °C for 2 h and then air quenched. In samples with ≥12000 ppm iodine, low viscosity salt phases were observed on the surface of the melts during cooling that solidified into a white coating upon cooling. These salts were identified as mixtures of KI, NaI, and Na2SO4 with X-ray diffraction (XRD). The iodine concentrations in glass specimens were analyzed with inductively-coupled plasma mass spectrometry and the overall iodine solubility was determined to be 10000 ppm by mass. Several crystalline inclusions of iodine sodalite, Na8(AlSiO4)6I2, were observed in the 24000 ppm specimen and were verified with micro-XRD and wavelength dispersive spectroscopy.

Citation: 
Riley BJ, MJ Schweiger, DS Kim, WW Lukens, BD Williams, C Iovin, CP Rodriguez, NR Overman, ME Bowden, DR Dixon, JV Crum, JS Mccloy, and AA Kruger.2014."Iodine Solubility in Low-Activity Waste Borosilicate Glass at 1000 °C."Journal of Nuclear Materials 452(1-3):178-188. doi:10.1016/j.jnucmat.2014.04.027
Authors: 
BJ Riley
MJ Schweiger
DS Kim
WW Lukens
BD Williams
C Iovin
CP Rodriguez
NR Overman
ME Bowden
DR Dixon
JV Crum
JS Mccloy
AA Kruger
Volume: 
452
Issue: 
Pages: 
178-188
Publication year: 
2014

In Situ One-Step Synthesis of Hierarchical Nitrogen-Doped Porous Carbon for High Performance Supercapacitors.

Abstract: 

Electrochemical performance of the existing state-of-the art capacitors is not very high, key scientific barrier is that its charge storage mechanism wholly depends on adsorption of electrolyte on electrode. We present a novel method for the synthesis of nitrogen -doped porous carbons and address the drawback by precisely controlling composition and surface area. Nitrogen-doped porous carbon was synthesized using a self-sacrificial template technique without any additional nitrogen and carbon sources. They exhibited exceptionally high capacitance (239 Fg-1) due to additional pseudocapacitance originating from doped nitrogen. Cycling tests showed no obvious capacitance decay even after 10,000 cycles, which meets the requirement of commercial supercapacitors. Our method is simple and highly efficient for the production of large quantities of nitrogen-doped porous carbons.

Citation: 
Jeon JW, R Sharma, P Meduri, BW Arey, HT Schaef, J Lutkenhaus, JP Lemmon, PK Thallapally, MI Nandasiri, BP McGrail, and SK Nune.2014."In Situ One-Step Synthesis of Hierarchical Nitrogen-Doped Porous Carbon for High Performance Supercapacitors."ACS Applied Materials & Interfaces 6(10):7214-7222. doi:10.1021/am500339x
Authors: 
JW Jeon
R Sharma
P Meduri
BW Arey
HT Schaef
J Lutkenhaus
JP Lemmon
PK Thallapally
MI Nasiri
BP McGrail
SK Nune
Instruments: 
Volume: 
6
Issue: 
10
Pages: 
7214-7222
Publication year: 
2014

Microstructural Response of Variably Hydrated Ca-Rich Montmorillonite to Supercritical CO2.

Abstract: 

We report on ab initio molecular dynamics simulations of Ca-rich montmorillonite systems, in different hydration states in the presence of supercritical CO2. Analysis of the molecular trajectories provides estimates of the relative H2O:CO2 ratio per interspatial cation. The vibrational density of states in direct comparison with dipole moment derived IR spectra for these systems provide unique signatures that can used to follow molecular transformation. In a co-sequestration scenario, these signatures could be used to identify the chemical state and fate of Sulfur compounds. Interpretation of CO2 asymmetric stretch shift is given based on a detailed analysis of scCO2 structure and intermolecular interactions of the intercalated species. Based on our simulations, smectites with higher charge interlayer cations at sub-single to single hydration states should be more efficient in capturing CO2, while maintaining caprock integrity. This research would not have been possible without the support of the office of Fossil Energy, Department of Energy. The computational resources were made available through a user proposal of the EMSL User facility, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory.

Citation: 
Lee MS, BP McGrail, and VA Glezakou.2014."Microstructural Response of Variably Hydrated Ca-Rich Montmorillonite to Supercritical CO2."Environmental Science & Technology 48(15):8612-8619. doi:10.1021/es5005889
Authors: 
MS Lee
BP McGrail
VA Glezakou
Instruments: 
Volume: 
48
Issue: 
15
Pages: 
8612-8619
Publication year: 
2014

Structures and Stabilities of (MgO)n Nanoclusters.

Abstract: 

Global minima for (MgO)n structures were optimized using a tree growth−hybrid genetic algorithm in conjunction with MNDO/MNDO/d semiempirical molecular orbital calculations followed by density functional theory geometry optimizations with the B3LYP functional. New lowest energy isomers were found for a number of (MgO)n clusters. The most stable isomers for (MgO)n (n > 3) are 3-dimensional. For n < 20, hexagonal tubular (MgO)n structures are more favored in energy than the cubic structures. The cubic structures and their variations dominate after n = 20. For the cubic isomers, increasing the size of the cluster in any dimension improves the stability. The effectiveness of increasing the size of the cluster in a specific dimension to improve stability diminishes as the size in that dimension increases. For cubic structures of the same size, the most compact cubic structure is expected to be the more stable cubic structure. The average Mg−O bond distance and coordination number both increase as n increases. The calculated average Mg−O bond distance is 2.055 Å at n = 40, slightly smaller than the bulk value of 2.104 Å. The average coordination number is predicted to be 4.6 for the lowest energy (MgO)40 as compared to the bulk value of 6. As n increases, the normalized clustering energy ΔE(n) for the (MgO)n increases and the slope of the ΔE(n)vs n curve decreases. The value of ΔE(40) is predicted to be 150 kcal/mol, as compared to the bulk value ΔE(∞) = 176 kcal/mol. The electronic properties of the clusters are presented and the reactive sites are predicted to be at the corners.

Citation: 
Chen M, AR Felmy, and DA Dixon.2014."Structures and Stabilities of (MgO)n Nanoclusters."Journal of Physical Chemistry A 118(17):3136-3146. doi:10.1021/jp412820z
Authors: 
M Chen
AR Felmy
DA Dixon
Instruments: 
Volume: 
118
Issue: 
17
Pages: 
3136-3146
Publication year: 
2014

Oxidative Remobilization of Technetium Sequestered by Sulfide-Transformed Nano Zerovalent Iron.

Abstract: 

The dissolution of Tc(IV) sulfide and concurrent transformation of sulfidated ZVI during 2 oxidation were examined. Kinetic data obtained with 10 mL batch reactors showed that Tc(VII) 3 reduced by sulfidated nZVI has significantly slower reoxidation rates than Tc(VII) reduced by 4 nZVI only. In a 50 mL batch reactor, initial inhibition of Tc(IV) dissolution was apparent and 5 lasted until 120 hours at S/Fe = 0.112, presumably due to the redox buffer capacity of FeS. This 6 is evidenced by the parallel trends in oxidation-reduction potentials (ORP) and Tc dissolution 7 kinetics. Mӧssbauer spectra and micro X-ray diffraction of S/Fe = 0.112 suggested the 8 persistence of FeS after 24-h oxidation although X-ray photoelectron spectroscopy indicated 9 substantial surface oxidation. After 120-h oxidation, all characterizations showed complete 10 oxidation of FeS, which further indicates that FeS inhibits Tc oxidation. X-ray absorption 11 spectroscopy for S/Fe = 0.011 showed significantly increasing percentage of TcS2 in the solid 12 phase after 24-h oxidation, indicating TcS2 is more resistant to oxidation than TcO2. At S/Fe = 13 0.112, the XAS results revealed significant transformation of Tc speciation from TcS2 to TcO2 14 after 120-h oxidation at S/Fe = 0.112. Given that no apparent Tc dissolution occurred during this 15 period, the speciation transformation might play a secondary role in hindering Tc oxidation, 16 especially as redox buffer capacity approached depletion.

Citation: 
Fan D, R Anitori, BM Tebo, PG Tratnyek, JS Lezama Pacheco, RK Kukkadapu, L Kovarik, MH Engelhard, and ME Bowden.2014."Oxidative Remobilization of Technetium Sequestered by Sulfide-Transformed Nano Zerovalent Iron."Environmental Science & Technology 48(13):7409-7417. doi:10.1021/es501607s
Authors: 
D Fan
R Anitori
BM Tebo
PG Tratnyek
JS Lezama Pacheco
RK Kukkadapu
L Kovarik
MH Engelhard
ME Bowden
Instruments: 
Volume: 
48
Issue: 
13
Pages: 
7409-7417
Publication year: 
2014

Automated High-Pressure Titration System with In Situ Infrared Spectroscopic Detection.

Abstract: 

A fully automated titration system with infrared detection was developed for investigating interfacial chemistry at high pressures. The apparatus consists of a high-pressure fluid generation and delivery system coupled to a high-pressure cell with infrared optics. A manifold of electronically actuated valves is used to direct pressurized fluids into the cell. Precise reagent additions to the pressurized cell are made with calibrated tubing loops that are filled with reagent and placed in-line with the cell and a syringe pump. The cell’s infrared optics facilitate both transmission and attenuated total reflection (ATR) measurements to monitor bulk-fluid composition and solid-surface phenomena such as adsorption, desorption, complexation, dissolution, and precipitation. Switching between the two measurement modes is accomplished with moveable mirrors that direct radiation from a Fourier transform infrared spectrometer into the cell along transmission or ATR light paths. The versatility of the high-pressure IR titration system is demonstrated with three case studies. First, we titrated water into supercritical CO2 (scCO2) to generate an infrared calibration curve and determine the solubility of water in CO2 at 50 °C and 90 bar. Next, we characterized the partitioning of water between a montmorillonite clay and scCO2 at 50 °C and 90 bar. Transmission-mode spectra were used to quantify changes in the clay’s sorbed water concentration as a function of scCO2 hydration, and ATR measurements provided insights into competitive residency of water and CO2 on the clay surface and in the interlayer. Finally, we demonstrated how time-dependent studies can be conducted with the system by monitoring the carbonation reaction of forsterite (Mg2SiO4) in water-bearing scCO2 at 50 °C and 90 bar. Immediately after water dissolved in the scCO2, a thin film of adsorbed water formed on the mineral surface, and the film thickness increased with time as the forsterite began to dissolve. However, after approximately 2.5 hours, the trend reversed, and a carbonate precipitate began to form on the forsterite surface, exposing dramatic chemical changes in the thin-water film. Collectively, these applications illustrate how the high-pressure IR titration system can provide molecular-level information about the interactions between variably wet scCO2 and minerals relevant to underground storage of CO2 (geologic carbon sequestration). The apparatus could also be utilized to study high-pressure interfacial chemistry in other areas such as catalysis, polymerization, food processing, and oil and gas recovery.

Citation: 
Thompson CJ, PF Martin, J Chen, P Benezeth, HT Schaef, KM Rosso, AR Felmy, and JS Loring.2014."Automated High-Pressure Titration System with In Situ Infrared Spectroscopic Detection."Review of Scientific Instruments 85(4):Article No. 044102. doi:10.1063/1.4870411
Authors: 
CJ Thompson
PF Martin
J Chen
P Benezeth
HT Schaef
KM Rosso
AR Felmy
JS Loring
Instruments: 
Volume: 
Issue: 
Pages: 
Publication year: 
2014

Ab Initio Thermodynamic Model for Magnesium Carbonates and Hydrates.

Abstract: 

An ab initio thermodynamic framework for predicting properties of hydrated magnesium carbonate minerals has been developed using density-functional theory linked to macroscopic thermodynamics through the experimental chemical potentials for MgO, water, and CO2. Including semiempirical dispersion via the Grimme method and small corrections to the generalized gradient approximation of Perdew, Burke, and Ernzerhof for the heat of formation yields a model with quantitative agreement for the benchmark minerals brucite, magnesite, nesquehonite, and hydromagnesite. The model shows how small differences in experimental conditions determine whether nesquehonite, hydromagnesite, or magnesite is the result of laboratory synthesis from carbonation of brucite, and what transformations are expected to occur on geological time scales. Because of the reliance on parameter-free first principles methods, the model is reliably extensible to experimental conditions not readily accessible to experiment and to any mineral composition for which the structure is known or can be hypothesized, including structures containing defects, substitutions, or transitional structures during solid state transformations induced by temperature changes or processes such as water, CO2, or O2 diffusion. Demonstrated applications of the ab initio thermodynamic framework include an independent means to evaluate differences in thermodynamic data for lansfordite, predicting the properties of Mg analogs of Ca-based hydrated carbonates monohydrocalcite and ikaite which have not been observed in nature, and an estimation of the thermodynamics of barringtonite from the stoichiometry and a single experimental observation.

Citation: 
Chaka AM, and AR Felmy.2014."Ab Initio Thermodynamic Model for Magnesium Carbonates and Hydrates."Journal of Physical Chemistry A 118(35):7469-7488. doi:10.1021/jp500271n
Authors: 
AM Chaka
AR Felmy
Instruments: 
Volume: 
118
Issue: 
35
Pages: 
7469-7488
Publication year: 
2014

Direct Evidence of Lithium-Induced Atomic Ordering in Amorphous TiO2 Nanotubes .

Abstract: 

In this paper, we report the first direct chemical and imaging evidence of lithium-induced atomic ordering in amorphous TiO2 nanomaterials and propose new reaction mechanisms that contradict the many works in the published literature on the lithiation behavior of these materials. The lithiation process was conducted in situ inside an atomic resolution transmission electron microscope. Our results indicate that the lithiation started with the valence reduction of Ti4+ to Ti3+ leading to a LixTiO2 intercalation compound. The continued intercalation of Li ions in TiO2 nanotubes triggered an amorphous to crystalline phase transformation. The crystals were formed as nano-islands and identified to be Li2Ti2O4 with cubic structure (a = 8.375 Å). The tendency for the formation of these crystals was verified with density functional theory (DFT) simulations. The size of the crystalline islands provides a characteristic length scale (∼5 nm) at which the atomic bonding configuration has been changed within a short time period. This phase transformation is associated with local inhomogeneities in Li distribution. On the basis of these observations, a new reaction mechanism is proposed to explain the first cycle lithiation behavior in amorphous TiO2 nanotubes.

Citation: 
Gao Q, M Gu, A Nie, F Mashayek, CM Wang, GM Odegard, and R Shahbazian-Yassar.2014."Direct Evidence of Lithium-Induced Atomic Ordering in Amorphous TiO2 Nanotubes ."Chemistry of Materials 26(4):1660-1669. doi:10.1021/cm403951b
Authors: 
Q Gao
M Gu
A Nie
F Mashayek
CM Wang
GM Odegard
R Shahbazian-Yassar
Instruments: 
Volume: 
26
Issue: 
4
Pages: 
1660-1669
Publication year: 
2014

In Situ Observation of Directed Nanoparticle Aggregation During the Synthesis of Ordered Nanoporous Metal in Soft Templates.

Abstract: 

The prevalent approach to developing new nanomaterials is a trial-and-error process of iteratively altering synthesis procedures and then characterizing the resulting nanostructures. This is fundamentally limited in that the growth processes that occur during synthesis can be inferred only from the final synthetic structure. Directly observing real-time nanomaterial growth provides unprecedented insight into the relationship between synthesis conditions and product evolution and facilitates a mechanistic approach to nanomaterial development. Here, we use in situ liquid-stage scanning transmission electron microscopy to observe the growth of mesoporous palladium in a solvated block copolymer (BCP) template under various synthesis conditions, and we ultimately determined a refined synthesis procedure that yields extended structures with ordered pores. We found that after sufficient drying time of the casting solvent (tetrahydrofuran, THF), the BCP assembles into a rigid, cylindrical micelle array with a high degree of short-range order but poor long-range order. Upon slowing the THF evaporation rate using a solvent-vapor anneal step, the long-range order was greatly improved. The electron beam induces nucleation of small particles in the aqueous phase around the micelles. The small particles then flocculate and grow into denser structures that surround, but do not overgrow, the micelles, forming an ordered mesoporous structure. The microscope observations revealed that pore disorder can be addressed prior to metal reduction and is not invariably induced by the Pd growth process itself, allowing for more rapid optimization of the synthetic method.

Citation: 
Parent LR, DB Robinson, PJ Cappillino, RJ Hartnett, P Abellan, JE Evans, ND Browning, and I Arslan.2014."In Situ Observation of Directed Nanoparticle Aggregation During the Synthesis of Ordered Nanoporous Metal in Soft Templates."Chemistry of Materials 26(3):1426-1433. doi:10.1021/cm4035209
Authors: 
LR Parent
DB Robinson
PJ Cappillino
RJ Hartnett
P Abellan
JE Evans
ND Browning
I Arslan
Instruments: 
Volume: 
26
Issue: 
3
Pages: 
1426-1433
Publication year: 
2014

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