Charles
H. Byers
IsoPro
International Inc.
2140
Santa Cruz Ave, #C304
Menlo
Park, CA 94025
Last Modified September 14, 2000
DOE
Chemical Sciences
Highlights
of Progress in Separations Sciences
Introduction
The
singular wartime success of the Manhattan project was, in large part, due
to the fact that project chemists, led by Glenn Seaborg, leveraged their
understanding of the chemistry of plutonium to industrial scale processes
for isolating this man-made element from irradiated fuel. Thus began
the intense interest of the Department of Energy and its predecessor agencies
in the science that underlies separation processes. The evolving
mission of the Department has now come full-circle as the scientific community
is enlisted to face the legacy of the Manhattan Project and the Cold War
era and to render the accumulated wastes manageable. Knowledge of
molecular level processes is required to characterize and treat these enormously
complex mixtures and to understand and predict the destiny of associated
contaminants in the environment.
February
7, 2000 During
the past several months a gathering of major accomplishments in the research
sponsored by Basic Energy Sciences by currently sponsored institutions
over the period of DOE's sponsorship has been undertaken.
The request for these inputs took the form of a letter to principal investigators
making the following request: "We
are seeking all of the examples of consequences of your work including
that of your past or present colleagues. These could be:
1. Commercialization of your ideas or developments,
2. Use of your research in a scientific application
that has been beneficial to society,
3. Any development that has led to paradigm-changing
understanding, 4.Any
development that has led to improvements in applications or practice." Responses
were collected from the majority of current principal investigators (PI).
The input varied greatly in style and content, some focusing on one of
the requested areas and others showing progress over the entire spectrum.
This report is divided into sections using the original request as a guideline
in subdividing the document. Therefore
some of the reports were subdivided and placed in multiple sections.
The name of the PI accompanies each report with the team details and addresses
compiled at the end of the document.
Table
of Contents Commercialized
Research Results Uranium
From Phosphate Rock Processing ( ORNL) Commercialization
Of CO2-Based Green Chemistry (Hank D. Cochran) Cleanup
of High-Level Waste Benefits from Fundamental Studies on Crown Ethers (Bruce
Moyer) Crown
Ethers for Removing Technetium from Alkaline Waste Solutions (Bruce Moyer) Basic
Research Reduced Cost of Uranium Production (Bruce Moyer) Low
Fouling Ultrafiltration and Microfiltration Aryl Polysulfone (Georges
Belfort) Separation
of Lanthanides (Ames Lab) Zirconium-Hafnium
Separation (ORNL -Ames) The
Calutrons - Isotope Separations (ORNL) Continuous
Annular Chromatography (ORNL) Emulsion
Phase Contactor (David DePaoli) Dielectric
Filter (David DePaoli) Micelles
and Microemulsions in Supercritical Fluids ( ClemYonker) Stabilized
Expanded Bed (David DePaoli) Products
in Commerce A
New Generation Of Selective Polymer Beads (Spiro Alexandratos) Bifunctional
Anion Exchange Resin for Groundwater
Cleanup (Bruce Moyer) Surfactants
For Dry Cleaning (Keith Johnston)16 Insoluble
Drug Formulations (Keith Johnston)16 Separation
Methods Technologies, Inc.(Mary
Wirth) Evaporative
Light Scattering Detector For HPLC (Georges Guiochon) Polymer
Chain Growth On Surfaces (Mary Wirth) Laser-Based
Detectors For Liquid Chromatography (Ed Yeung) Ionization
Laser Vaporization for Mass Spectrometry (Ed Yeung) Applications
of Small Drop Generation Technology (Basaran) High-Temperature
Fiberoptic Spectroscopic Instrumentation for the Magnesium
Industry (Sheng Dai) Spectroscopic
Sensors for the Aluminum Industry (Sheng Dai) Spectroscopic
Titanium Complex Sensors for the Titanium Industry (Sheng Dai) Research
Beneficial to Society Principle
of Bifunctionality (Spiro Alexandratos) Room
Temperature Ionic Liquids (Robin Rogers) Synergism
Changes Course of Research on Crown Ethers for Extraction of Metal Ions
(Bruce Moyer) Technical
Consulting Impact of ORNL Actinide Program (Sheng Dai) Surface
Chemistry Details of Alkyl Carboxylate Adsorption (Jan Miller) Flotation
Of Fine Particles in a Centrifugal Field (Jan Miller) Catalyst
Reactivity and Separations using H2O/CO2
Emulsions (Keith Johnston) Filtering
Protein Solutions (Georges Belfort) Paradigm-changing
understanding Appendix
C: A Brief History of DOE Chemistry
Support DOE
Chemical Sciences SRTALK process for removing technetium from nuclear waste A
fundamental understanding of the thermodynamics of such systems in fact
led to the prediction that sodium pertechnetate could be selectively separated
from the Hanford waste. In
subsequent process development, this prediction was validated through invention
of the SRTALK process. No
pre-treatment of the waste solution is necessary, and the technetium can
be recovered using a safe and inexpensive stripping process, regenerating
the crown ether for many more cycles with minimal generation of secondary
waste. Engineering tests with
a waste simulant in a cascade of centrifugal contactors by collaborators
at Argonne National Laboratory gave 89% removal of Tc from the waste, meeting
the experimental goal. Remarkably,
the tests gave a product stream concentrated 10-fold in sodium pertechnetate. Considering
that the source of the recovered Tc would be a substantially toxic and
complex waste, the remarkable purity of the Tc product would make for an
ideal feed for production of waste forms for final disposal, with
expected major cost savings. Given
the product purity, a practical application may be found.
A
chemical depiction of SRTALK is shown above. The
waste is a mixture of salts concentrated in sodium, potassium, hydroxide,
nitrate, nitrite, and carbonate, but with a trace of radioactive contaminants
such as 99Tc. Most of the
Tc is in the form of the negatively charged pertechnetate ion, which has
the formula TcO4-. The
crown ether complexes with sodium ions (Na+) as shown but can also complex
with potassium ions (K+). The
transfer of either of these metal ions into the solvent by the crown ether
must also be accompanied by a negatively charged ion. Among
the most easily transferred negative ion is pertechnetate with a selectivity
over nitrate on the order of a thousand to one. When
the solvent is contacted with water the sodium pertechnetate may be released
into the water, regenerating the crown ether for further extraction cycles. The
process is described by a 1995 patent and in numerous publications. The
governing fundamental principles are described in a series of papers from
the early 1990s continuing to the present. In
1999 a Lockheed Martin Technical Accomplishment Award recognized the development
of the SRTALK process. The
foundation leading to this development was provided by basic research supported
by the USDOE Office of Basic Energy Sciences, Chemical Sciences Division,
and the process development was supported under the USDOE Office of Technology
Development, Efficient Separations and Processing Integrated Program. The
CAC is one of the leading success stories resulting from an ORNL group
consisting of C.D. Scott, John Begovich, Charles Byers and several others
who performed the original research.The
annular device allows the continuous input of a feed mixture followed by
a separation in the annular space between two concentric slowly rotating
cylinders.The multiple products
are removed at different angular positions on the periphery.This
device can perform virtually all types of chromatographic separations.All
of the basic work was done at ORNL under Chemical Sciences sponsorship.It
was initially commercialized by IsoPro International Incorporated (http://www.isopro.net)
and its predecessor System Designs.The
interest here was in small laboratory scale units, research, and consulting.It
went into full-scale production in 1998 at Prior Separations Technology
(http://www.priorsep.com).During
the past year units have been placed in the precious metals industry, in
medical biotechnology, and in the food industry.The
initial phase of this introduction into commerce is very promising. Work at PNNL over the last 15 years has lead to
significant advances in our understandings of microemulsions in supercritical
fluids including CO2. The initial
discovery of the formation of microemulsions in compressible fluids (ethane)
was made in 1987 under the BES program ("Organized Molecular Assemblies
in the Gas Phase: Reverse Micelles and Microemulsions in Supercritical
Fluids." Gale, R.W.; Fulton, J.L.; Smith, R.D., J. Phys. Chem. 1987, (109):920-921).
The first studies to show the high solubility of fluorinated surfactants
("Observations on the Solubility of Surfactants and Related Molecules in
Carbon Dioxide at 50°C." Consani, K.A.; Smith, R.D., J. Supercritical
Fluids 1990, (3):51-65) and fluorinated chelates ("Solubility of Fluorinated
Metal Diethyldithiocarbamates in Supercritical Carbon Dioxide." Laintz,
K.E.; Wai, C.M.; Yonker, C.R.; Smith, R.D., J. Supercritical Fluids 1991,
(4):194-198) set the stage for the discoveries that followed. In this first
study of the solubility of fluorinated surfactants, appreciable amounts
of water were dissolved into CO2
and later studies by SAXS of one of these systems ("Aggregation of Amphiphilic
Molecules in Supercritical Carbon Dioxide: A Small Angle X-Ray Scattering
Study." Fulton, J.L.; Pfund, D.M.; McClain, J.B.; Romack, T.J.; Maury,
E.E.; Combes, J.R.; Samulski, E.T.; DeSimone, J.M.; Capel, M. Langmuir
1995, (11):4241-4249) showed the formation of reverse micelles. Much of
the subsequent work at PNNL was aimed at understanding the fundamental
properties that govern the behavior of these systems.
Initial studies on the measurements of the micelle
size and structure were conducted using light scattering on alkanes and
CO2
micelles. At PNNL, the early realization of the importance of using angstrom-wavelength
radiation (neutrons and x-rays) for characterization of micelle structures
led to the first SANS and SAXS studies of these colloidal systems in fluids.
In 1990, Fulton and other researchers at PNNL conducted the first SANS
studies of microemulsions in compressible fluids and measured the short-range
and highly attractive nature of these microemulsions droplets ("A Small-Angle
Neutron Scattering Study of Intermicellar Interactions in Microemulsions
of AOT, Water and Near-Critical Propane." Kaler, E.W.; Billman, J.F.; Fulton,
J.L.; Smith, R.D., J. Phys. Chem. 1991, (95):458-462). These SANS studies
used a cell designed at PNNL. In overcoming some of the limitations of
SANS sensitivity and the limited availability of SANS facilities at the
time, the method of SAXS for supercritical fluids and carbon dioxide was
developed at PNNL including the development of a high-pressure SAXS cell.
This work culminated in a collaborative study between Fulton and DeSimone
in which the first reported measurements were made of the size and geometry
of large (20 nm) surfactant and water aggregates using DeSimone polymeric
surfactants ("Aggregation of Amphiphilic Molecules in Supercritical Carbon
Dioxide: A Small Angle X-Ray Scattering Study." Fulton, J.L.; Pfund, D.M.;
McClain, J.B.; Romack, T.J.; Maury, E.E.; Combes, J.R.; Samulski, E.T.;
DeSimone, J.M.; Capel, M. Langmuir 1995, (11):4241-4249). This represented
a considerable advancement in our understanding of these systems since
large aggregates of this size had not previously been known to exist in
carbon dioxide.
In order to understand the nature of the high
solubility of fluorinated compounds in CO2,
researchers at PNNL measured the molecular interactions between CO2
and fluorinated compounds using Fourier Transform Infra-red spectroscopy
("Fourier Transform Infrared Spectroscopy of Molecular Interactions of
Heptafluoro-1-butanol or 1-Butanol in Supercritical Carbon Dioxide and
Supercritical Ethane." Yee, G.G.; Fulton, J.L.; Smith, R.D., J. Phys. Chem.
1992, (96):6172-6181). This study is widely cited in current efforts to
design new CO2 surfactant. Using
the same technique, the inter-molecular hydrogen bonding of nonionic surfactants
in CO2 was reported ("Aggregation
of Polyethylene Glycol Dodecyl Ethers in Supercritical Carbon Dioxide and
Ethane." Yee, G.G.; Fulton, J.L.; Smith, R.D., Langmuir 1992, (8):377-384).
The method of FTIR for studies of supercritical fluid microemulsion (including
CO2)
was developed at PNNL and techniques now used by others to probe water
properties in CO2 microemulsions
were first demonstrate at PNNL ("Reverse Micelles and Microemulsions in
Near-Critical and Supercritical Fluids." Smith, R.D.; Fulton, J.L.; Blitz,
J.P.; Tingey, J.M. J. Phys. Chem. 1990, (94):781-787). Using the full Lifshitz
theory, the van der Waals interaction between microemulsion droplets in
SC fluids was calculated ("Interdroplet Attractive Forces in AOT Water-in-Oil
Microemulsions Formed in Subcritical and Supercritical Solvents." Tingey,
J.M.; Fulton, J.L.; Smith, R.D., J. Phys. Chem. 1990, (94):1997-2004) helping
to define the way that colloid particles behave in fluids such as carbon
dioxide. There are now over 40 peer-reviewed scientific papers dealing
with microemulsions in supercritical fluids that have resulted from work
at PNNL over the last decade generated under BES support.
In recent advances in surfactant technology for
CO2,
a new system has been reported by Fulton at PNNL in which a conventional,
inexpensive hydrocarbon surfactant (AOT) was used in combination with lesser
amounts of a fluorinated co-surfactant to synthesize and stabilize large
metallic (Ag) particles in CO2
("Synthesizing and Dispersing Silver Nanoparticles in a Water-in-Supercritical
Carbon Dioxide Microemulsion." Ji, M.; Chen, X.; Wai, C.M.; Fulton, J.L.,
J. Am. Chem. Soc. 1999, (121): 2631-2632) ("Properties of an AOT Microemulsion
formed in Supercritical Carbon Dioxide using a Fluorinated Co-Surfactant",
Fulton, J.L.; Jackson, K. 215th ACS National Meeting in Dallas, Spring
1998). This approach decreases the reliance on the more expensive fluorinated
compounds while still stabilizing macro-molecular species.
Work at Argonne National Laboratory on the design
of novel actinide complexants funded by the Office of Basic Energy Sciences
(Division of Chemical Sciences) has led to the development of a new chelating
ion-exchange resin, called Diphonix(tm), which overcomes all of the limitations
associated with previous materials. This resin, one of a class of so-called
dual-mechanism bifunctional polymers, employs geminally-substituted diphosphonic
acid functional groups (among the most powerful metal ion complexing groups
known) chemically bonded to a sulfonated styrene-based polymer matrix.
The hydrophilic and non-selective sulfonic acid group provides access of
the ions into the polymer matrix, while the gem-diphosphonic acid group
provides specificity towards actinides and other cations complexed by diphosphonic
acids. This combination provides an ion-exchange resin with rapid uptake
kinetics, excellent selectivity over alkali metal cations, and unparalleled
affinity for a number of toxic and/or radioactive cations, even from highly
acidic solution. Adsorbed actinide ions can be recovered and the resin
regenerated simply by eluting the resin with a solution of a commercially
available, water-soluble diphosphonic acid. For non-actinides, a mineral
acid solution of appropriate concentration (2-6 M) typically suffices.
The Diphonix resin, now available commercially
from EiChroM Industries, Inc. (Darien, IL), has numerous actual and potential
applications in industrial and nuclear waste treatment, reagent purification,
and chemical analysis. For example, the resin has already served as the
basis for a new process for the removal of uranium from mixed wastes resulting
from Davies-Gray analyses. In addition, Diphonix has been employed in a
new procedure for the isolation of actinides from large-volume soil and
water samples for subsequent determination. Finally, plant-scale removal
of iron from copper electrowinning solutions has been successfully demonstrated.
A number of additional applications, including the treatment of potable
water and the preparation of high purity reagents for use in the manufacture
of semiconductors, are now under investigation throughout the United States.
In recognition of its potential significance in
separations science, the Diphonix resin was selected as one of the "100
most technologically significant new products" of 1994 by R&D magazine.
Building on research funded by the Office of Basic
Energy Sciences (Division of Chemical Sciences) on the design of novel
metal ion sorbents and of improved extractants for actinides and selected
fission products, researchers at Argonne National Laboratory have developed
a process by which Y-90 of extremely high chemical and radiochemical purity
can be prepared. Briefly, the process involves the passage of an acidified
solution containing Y-90, its Sr-90 parent, and its Zr-90 daughter through
a series of columns packed with unique solid sorbents capable of selectively
removing either strontium or yttrium from aqueous solution. First, a nitric
acid solution containing the Sr-90/Y-90/Zr-90 mixture is passed through
a series of three strontium-selective extraction chromatographic columns,
each of which reduces the Sr-90 content of the solution by a factor of
1000-10,000. After acidity adjustment, the solution is passed through a
final column that selectively retains yttrium. Residual Sr-90, Zr-90, and
any impurities present are rinsed from the column with nitric acid and
discarded. Finally, the purified Y-90 is stripped from the column with
a small volume of dilute nitric acid.
Continued progress in the clinical application
of Y-90 is dependent upon the availability of an adequate supply of inexpensive
and highly pure material. The process described here represents a significant
step toward ensuring the availability of such material. The process yields
a carrier-free product of very high chemical and radiochemical purity,
minimizing the danger of bone marrow suppression in patients treated with
the material. It requires comparatively few manipulations, an important
consideration given that the levels of activity required typically require
remote handling. Because the process involves the purification of the Sr-90
feedstock each time the Y-90 is recovered, radiolytic degradation products
do not accumulate in the feed, thereby prolonging its useful life and minimizing
the volume of wastes generated and associated disposal costs. (This feedstock,
it should be noted, is itself actually a solution of spent nuclear fuel
wastes from DOE reactors. In effect then, the Y-90 Process serves to convert
nuclear waste to nuclear medicine.) To date this process has been applied
only to the preparation of Y-90, it can, with little modification, be adapted
to the isolation of several other radionuclides of interest in therapeutic
or diagnostic nuclear medicine.
Building on research funded by the Office of Basic
Energy Sciences (Division of Chemical Sciences) on the effect of organic
solvent and ligand stereochemistry on metal ion partitioning in crown-ether
based extraction systems, researchers at Argonne National Laboratory have
developed a process (called SREX, for strontium extraction) that provides
a means of selectively and efficiently removing Sr-90 from acidic nuclear
waste solutions. Briefly, this process combines a highly selective strontium
extractant (bis 4,4'(5') tert-butylcyclohexano-18-crown-6) with a stable,
non-toxic diluent (e.g., 1-octanol) to yield a process solvent capable
of extracting strontium from wastes containing a wide range of nitric acid
concentrations and permitting its recovery in a comparatively small volume
of water or dilute nitric acid.
SREX represents an important breakthrough in separations
technology. In the field of nuclear waste processing, it promises to greatly
simplify waste handling and storage and to reduce the quantity of waste
requiring expensive vitrification and deep geologic disposal. In addition,
it permits the ready recovery of high purity Sr-90, material that could
be employed as a fuel in thermoelectric power sources. SREX has also provided
the basis for a new generation of more versatile waste-processing techniques,
those involving the simultaneous removal of several hazardous radionuclides
from a given waste stream. The use of such techniques is certain to reduce
the cost of waste treatment still further. Finally, SREX has found application
in separations problems far removed from the treatment of defense wastes.
It has, for example, served as the basis for a new approach to the preparation
of Y-90 for radioimmunotherapy and of improved analytical-scale separations
methods for the isolation of radiostrontium and lead from environmental,
biological, and geological samples. In short, SREX is a generic separations
technology that not only represents a solution to an important and long-standing
problem in nuclear waste treatment, but that also has numerous actual and
potential applications to separations problems in a variety of other areas.
Host-Guest
Complexation (Donald Cram) The concept of host-guest complexation constituted a major paradigm
shift in molecular level understanding of ion sequestration. Long-time
Separations and Analysis grantee, Professor Donald J. Cram, now retired
from the Chemistry Department of UCLA, shared the 1987 Nobel Prize in Chemistry
for his contributions to this area. Professor Cram visualized molecules
with size and charge characteristics sufficiently unique that one could
be designed to specifically attract and hold only one metal ion.
He then proceeded to develop synthetic routes for their production.
In a 1989 conversation with this writer, Professor Cram was obviously most
pleased with having “constructed bits of matter that had not heretofore
existed.” The abstract of his work presented in Summaries
of FY 1977 Research in the Chemical Sciences, (DOE/ER-0002), the earliest
available edition, is quoted here:
“MULTIHETERO MACROCYCLES THAT COMPLEX METAL IONS
By 1985 the Chemistry Department had changed its name to the Chemistry
and Biochemistry Department but the title of Professor Cram’s grant remained
the same. The abstract for the 1985 Summary Book, (DOE/ER-0144/3,
DE85008926) reads:
“The general objectives of this research are to design, synthesize,
and evaluate new types of cyclic and polycyclic organic ligand systems
for their abilities to complex and lipophilize selectively guest metal
ions. Correlations are sought between ligand structures and their
binding free energies, their rates of complexation-decomplexation, and
their solvation effects. Desired properties are high selectivity,
rapid rates of complexation, and incorporation of detecting systems into
the ligand. The principles of complementarity of host and guest and
of host preorganization are being tested as guides in ligand design.
Organized arrays of most of the functional groups of organic chemistry
are being tested as ligating sites. Particular emphasis is placed
on those systems that contain weakly basic nitrogen, sulfur in various
oxidation states, and carbonyl groups of various types. Synthetic
methods are being developed which lead to enforced preorganization of binding
sites. Solvent effects on binding are being studied.”
In the intervening years Professor Cram introduced cryptands, spherands,
and hemispherands. The contributions can be gauged by the following
extract from his abstract in the 1980 Summary Book, (DOE/ER-0079):
“Spherands are the only known ligand systems whose binding of metal
cations is driven by the release of electron-electron nonbonded repulsion.
They are composed of rigid carbocyclic frameworks that place heteroatoms
in a spherical arrangement around enforced cavities. They are the
only known synthetic compounds which, in the non-complexed state, contain
holes. Spherands are being studied that are composed of six anisyl
units strung together in a ring system by aryl-aryl bonds at their 2,6
positions. They are highly cation selective in forming meatllospherium
salt complexes of unusual stability. Hemispherands are hybrids of
crown ethers and spherands. A large number of structural variants
are being prepared and examined which contain anisyl, methoxy-cyclohexyl,
urea, pyridine, pyridine oxide, and amide units.”
One only need peruse the work on solvent extraction and ligand design
presented in this document to recognize the importance of the contributions
of Professor Cram to the fundamental science that underlies solvent extraction.
(This section was prepared by the Program Manger, Richard L. Gordon.
No implication of an endorsement by Professor Cram is intended. Professor
Cram has summarized his career in an autobiography, "From Design to Discovery,"
by Donald J. Cram, published by The American Chemical Society, Washington,
DC, 1990. A discussion of host-guest complexation, its underlying
concepts, and the use of CPK models to guide the research begins on page
50.)
External
Field Effects in Multiphase Separations(David
DePaoli, Osman Basaran) Single-Molecule
Diagonistics Reveal Mechanism of Chromataographic Separations (Ed Yeung) Chromatographic
separation is a statistical process involving many repeated interactions
between the molecules in a moving stream and an immobilized surface.
The standard picture is that molecules occasionally bind to the surface
and become delayed relative to the bulk motion. For the first time,
images of individual protein molecules are recorded as they approach a
fused-silica surface. Charge interaction causes the molecules to be trapped
in the interfacial liquid layer for tens of milliseconds. This constitutes
the direct verification of the statistical theory of chromatography. Microscopic
reversibility is conserved. However, the molecules were not immobilized
as portrayed in conventional models. They are simply held near the
surface by attractive forces and can diffuse freely within the interfacial
layer. The interaction distances are also found to be much longer
than predicted by the electrostatic double-layer thickness. The results
imply that molecule/surface interactions are considerably more efficient
than expected. This is perhaps why in nature cell-surface receptors
work so well in recognizing very low concentrations of target molecules.
High
Sensitivity Infrared Spectroscopy of Silica/Solution Interfaces (Joel M.
Harris) Relaxation
Methods to Measure Sorption/Desorption Rates (Joel M. Harris) Another extremely important outcome of the research is the discovery
of an effective way to test and develop intermolecular potentials that
are used in simulations ("Direct Modeling of XAFS Spectra from Molecular
Dynamics Simulations." Palmer, B.J.; Pfund, D.M.; Fulton, J.L., J. Phys.
Chem. 1996, (100):13393-13398.). These ion-water and ion-ion intermolecular
potentials are used both for high-temperature and ambient water studies.
The existing water models that have been developed for ambient conditions
do not accurately predict structure in high-temperature water. From the
XAFS experimental results improvements hav been implemented to these models
that have significantly boosted their performance by use of more realistic
potentials.
Many different ion-water systems have been studied with XAFS starting
with an early landmark investigation of Sr2+ in supercritical
water. ("An XAFS Study of Strontium Ions and Krypton in Supercritical Water.",
Pfund, D.M.; Darab, J.G.; Fulton, J.L.; Ma, Y., J. Phys. Chem. 1994, (98):13102-13107.)
We have found significant dehydration occurring under supercritical water
conditions for mono- and di-valent cations (Sr2+ and Rb+)
("Rubidium ion hydration in ambient and supercritical water." Fulton, J.L.;
Pfund, D.M.; Wallen, S.L.; Newville, M.; Stern, E.A.; Ma, Y., J. Chem.
Phys. 1996, (105):2161-2166.) and for a monovalent anion (Br-)
("Hydration of Bromide Ion in Supercritical Water: An X-ray Absorption
Fine Structure and Molecular Dynamics Study." Wallen, S.L.; Palmer, B.J.;
Pfund, D.M.; Fulton, J.L.; Newville, M.; Ma, Y.; Stern, E.A., J. Phys.
Chem. A 1997, (101):9632-9640.) More recently we have explored NiBr2 hydration
and ion pairing in high-temperature water. ("A Transition in the Ni2+
Complex structure from six- to four-coordinate upon formation of ion pair
species in supercrtical water: an XAFS NIR and MD study." Hoffmann, M.M.;
Darab, J.G.; Palmer, B.J.; Fulton, J.L., J. Phys. Chem. A 1999, (42):8471-8482)
At room temperature, the octahedral Ni2+(H2O)6
species persists at all salt concentrations. This species is still prevalent
at 325°C, but at higher temperatures it is replaced by four-coordinate
structures. Above 425°C, at moderate pressures up to 700 bar, the stable
structures are a family of four-coordinated species (NiBr(H2O)3•Br,
NiBr2(H2O)2, NiBr3(H2O)•Na)
where the degree of Br- adduction and replacement of H2O
in the inner shell depends upon the overall Br- concentration.
The most likely symmetry of these species is a distorted tetrahedron. Thus,
we have completed the definitive structural characterization of several
ionic species at high temperatures. Most recently we have investigated
the structure about Cu+ above 300°C. We have found an unusual linear
copper halide species that has now been characterized for the first time.
Many other systems are currently under study using this powerful technique.
Evidence of a Wall Friction Effect in the Consolidation
of Beds of Packing Materials in Chromatographic Columns. Georges
Guiochon, Eric Drumm and Djamel Cherrak. Journal of Chromatography
A, 835 (1999) 41-58.
Simulation of Wall Friction Effects in High Performance
Liquid Chromatography (HPLC) Columns. B. G. Yew, E. C. Drum and G.
Guiochon. Proceedings of the Fourth International Conference on Constitutive
Laws for Engineering Materials: Experiment, Theory, Computation and Applications,
Troy, NY, 1999, pp. 513-516.
On-column Visualization of Sample Migration in Liquid
Chromatography. R. Andrew Shalliker, B. Scott Broyles and Georges
Guiochon. Analytical Chemistry, 72 (2000) 323-332.
Aggregation and association in alcohols have typically
been used to study hydrogen bonding dynamics in solutions. Methanol can
associate through hydrogen bonding, and details about the dynamics of this
interaction in solution have been investigated for both liquid and supercritical
conditions ("Density and temperature effects on the hydrogen bond structure
of liquid methanol" Wallen, S.L.; Palmer, B.J.; Garrett, B.C.; Yonker,
C.R., J Phys Chem 1996, (100):3959-3964 and "Pressure and temperature effects
on the hydrogen-bond structures of liquid and supercritical fluid methanol".
Bai, S.; Yonker, C.R., J Phys Chem A 1998, (102):8641-8647). The nuclear
shielding constant is an absolute measure of the electronic distribution
about the nucleus and its effect on the observed magnetic moment of that
nucleus in the applied magnetic field, which is sensitive to a molecule's
chemical structure and local solvation environment. For methanol the CH3,
and OH groups will each experience their own shielding environments. One
assumes that changes in pressure or temperature affect the non-specific
contributions to the nuclear shielding in a similar manner for all the
different group's resonances. Thus, the difference between the shielding
of the groups (Dd) can be related to the specific
interactions in solution, which is due to hydrogen bonding of the OH group.
For methanol, the Dd
data was obtained over a wide range of pressure and temperature (50 to
500°C and 2 kbar). A dramatic change of Dd
in the vicinity of the methanol critical point, 239.4°C, at low pressure
was observed. This is related to the large changes in density and thus
hydrogen bonding of solution in this region. As pressure is increased through
this temperature region, hydrogen bonding increases which contributes to
a change in shielding of the nucleus and thus to a change in Dd.
The slope ((¶Dd/¶P)T)
for methanol increases with increasing temperature. This observation can
be explained within the framework of the hydrogen bonding occurring in
solution. Hydrogen bonding removes electron density from the vicinity of
the 1H nucleus contributing to the deshielding of the proton. Qualitatively,
an increase in Dd correlates with an increase
in the deshielding of the OH proton relative to that of the CH3 group
and thus an increase in hydrogen bonding in solution. This could be due
to a change in both the extent and strength of the hydrogen bond network
at high temperatures as one changes pressure as compared to a change in
hydrogen bond strength alone at low temperatures with increasing pressure.
The results demonstrate that increasing temperature at constant pressure
tends to decrease the extent of hydrogen bonding in methanol, while increasing
pressure at constant temperature increases hydrogen bonding in solution.
One would anticipate that increasing temperature would more readily disrupt
hydrogen bonds in solution. Increasing pressure at high temperatures should
have a large effect on the solutions' hydrogen bond network, contributing
to the larger slope ((¶Dd/¶P)T)
seen at the higher temperatures. However, the NMR chemical shift data clearly
indicates that significant hydrogen bond interactions exist for methanol
at high temperatures and pressures and in the critical region.
Department of Chemistry Thanks
in advance for your help. Dick
Gordon Charlie
Byers SUPPORT OF BASIC CHEMISTRY
BY
THE DEPARTMENT OF ENERGY & PREDECESSOR AGENCIES
The Beginning
In 1947, the Atomic Energy Commission's (AEC's) chemistry research program
was inherited from the wartime Manhattan Project. Mostly, that program
had been directed at the needs of the plutonium project, e.g., chemical
processes for separating uranium, plutonium, and fission products, necessarily
developed on a micro-scale. There were also studies of the chemistry
of plutonium, neptunium, etc. Naturally, the effects of extremely
high levels of radiation were important, as was the problem of radioactive
wastes. Unusually high purities were required in some key materials,
e.g., graphite, uranium, and zirconium. For the gaseous diffusion
project (isotopic enrichment of uranium) the chemistries of UF6, diffusion
barriers, etc. were studied.
Late-War and Early Post-War Transition
In 1945-47, after the plutonium production and processing facilities
were operating successfully, the extreme concentration on process development
and trouble-shooting was relaxed. Longer range studies were undertaken,
such as searches for transplutonium elements and studies of their properties,
chemical studies of nuclear reactions, the chemistry of power reactors
and breeders, isotope effects, and radiation chemistry.
During that period the research was done at five major laboratories.
The Clinton Laboratories in Tennessee became the Oak Ridge National Laboratory.
Some management problems were experienced until a change of contractors
was made, but then the Laboratory flourished. The University of Chicago's
laboratories supporting the plutonium project were moved from campus to
Du Page County and became the Argonne National Laboratory. Universities
in the northeastern U.S. formed the Associated Universities, Inc., which
signed a contract in 1946 with the Army to install and operate Brookhaven
National Laboratory. The University of California Radiation Laboratory,
where Emest O. Lawrence had launched the cyclotron, became the Lawrence
Radiation Laboratory. At Iowa State University, Frank Spedding's
wartime laboratory for uranium and plutonium metallurgy and associated
fields became the Ames Laboratory. During these changes there had
not yet begun the support of individual investigators' projects at universities.
Early AEC Days
In the period 1946-48 several thrusts were shaping the framework for
research support. Vannevar Bush's report, "Science, the Endless Frontier"
provided a powerful impetus to major involvement of the Federal Government
in scientific research and technological development. A National
Science Foundation (or National Research Foundation) was being debated.
The Office of Naval Research was moving aggressively to keep alive the
scientific capabilities built up during the war. The Atomic Energy
Act of 1946 included a broad authority and requirement for conducting research
with several purposes. These included: assisting and fostering private
R&D to encourage maximum scientific progress in understanding and use
of nuclear phenomena, and conducting a federally supported R&D effort
to assure the Government of adequate scientific and technological accomplishment.
The Division of Research was a statutory division "authorized and directed
to make arrangements for conduct of R&D activities relating to" nuclear
processes, production of atomic energy, utilization of fission and radioactive
materials, etc. The language was important: "The commission
is directed to ...insure the continued conduct of R&D [in the above
fields] and to assist in the acquisition of an ever-expanding fund of theoretical
and practical knowledge in such fields."
The size of the chemical research program taken over by the Division
of Research of the AEC in 1947 was about $6-7 million and was at first
still confined to Oak Ridge, Argonne, Brookhaven, Berkeley, and Ames (in
order of decreasing size).
Honeymoon, 1947-52
The first year or two were hectic times for the Commission-- questions
were faced such as: What laboratories? Who will manage them, government
or private contractors? How will power reactor development be handled?
What role will security matters play? But, after these questions
had settled down, there was a honeymoon period in relations with Congress,
within the Executive Branch, and with the general public. Why a honeymoon?
Because during the war, atomic energy and radar had given science and technology
a reputation for being capable of almost anything and this was reinforced
by the Bush and Smythe reports.
In those five years the Chemistry Research Program approximately doubled,
to $10-12 million. Much of the increase was due to establishment
of the university contract program: from nothing in 1947 to $2-3 million
in 1951. The makeup of the program also changed, becoming more basic
in nature and broader in its content. Still, the research topics
were easily identified as being AEC-related. The important areas
included solution chemistry of inorganic ions and complexes; radiation
chemistry -- how to deal with radiation and how to use it to advantage;
chemical and nuclear studies of heavy elements; isotope effects; high temperature
chemistry; and materials chemistry. It was about this time that one
of us (Miller) joined the staff of the AEC Division of Research.
The initial administrative arrangements of the University Contract Research
Program were borrowed heavily from on-going programs of other agencies,
especially NIH and ONR. Examples were: 8% overhead, no academic-year
salary for academic principal investigators, only 2 months of summer salary,
the 2-column budget. Fixed-price contracts were used behaving much
like grants.
About 1952 the arrangements changed to "joint participation" cost sharing.
One-column budgets reflected total costs (full overhead, academic-year
salaries, etc.), and only in the total were the respective government and
university contributions specified. The contracts were almost all
unclassified. In parallel fashion, the national laboratory programs
were becoming more unclassified.
New long-range research in uranium and thorium chemistry was started,
aimed at bases for their processing. A lot of geochronology and isotope
geology was encouraged, giving an important initial boost to these now
very important fields.
"Honeymoon's Over" (1952-56)
These were the first Eisenhower years, with tight budgets. Chemistry
Programs held at the same budget level or moved up slowly, at around $15
million, with the content of the program approximately stable.
Post-Sputnik (1956-60)
Sputnik shook our national pride, the country was reminded that progress
in science and technology was absolutely critical, and the AEC chemistry
research programs benefited, moving in 1958 to about $22 million, including
$5 million for 180 contracts "offsite," i.e., at universities.
The Joint Committee on Atomic Energy (JCAE) held hearings for two weeks
in February of 1958 and established a record that basic research related
to atomic energy was at an inadequate level, not enough to take advantage
of the scientific opportunities or to serve AEC needs. JCAE, with
a few exceptions, had always been a sort of kindly, but stern, grandfather.
Also in this period, under the aegis of the President's Science Advisory
committee, the Seaborg report, "Scientific Progress, the Universities,
and the Federal Government", was issued, endorsed by President Eisenhower.
It made some very important observations:
"Basic research and the education of scientists go best together,” and
"they are inseparable functions of universities."
The Seaborg era at AEC saw relative stability and slow growth.
The Westheimer report (1965, National Research Council) recommended a higher
level of support for research and instrumentation, and more basic research
in the federal laboratories. It was valuable as a planning tool,
but precipitated no major changes. (Interestingly, a circulated draft
of the report covered all of the federal science agencies except AEC!)
The 1970's -- Transitions
The energy shortage of 1973 led to a time of great change, with major
upheavals in AEC's research program. The content of Chemistry Programs
was broadened into topics related to solar, geothermal, fossil, and other
energy areas. Physical Research was reorganized:
Materials chemistry was divided along properties- vs. -processes lines,
and the properties part was moved to a (renamed) Materials Sciences Division.
Chemistry Programs was moved into a newly created Molecular, Mathematical,
and Geosciences Division.
Then in 1977 ERDA was dissolved, and its programs were taken over by
the new Department of Energy. Redirection of programs, addition of
administrative procedures and organizational changes continued. Molecular
Sciences became the Division of Chemical Sciences, and a new Division of
Engineering, Mathematical and Geosciences initiated a new program of basic
research in engineering; one of us (Pierce) headed both of these divisions
and their predecessors for about five years, until sanity was restored.
There were key changes of programmatic emphasis during all this:
From physical chemistry to chemical physics, especially combustion-related.
In mass spectrometry, from nuclear systems to coal structure/chemistry
and hydrocarbon mixtures.
Introduction of new areas of emphasis: catalysis, surface chemistry,
biomass conversions.
Major Research Facilities
From the 1950's on, AEC and its successor agencies took the lead in
providing major, expensive research facilities or products required for
research. Most of these have been particle accelerators, but also
among them are research reactors, radiation facilities, a laser-centered
combustion diagnostics laboratory, and the separation of enriched isotopes
by electromagnetic separation. In the early years most of these facilities
were used nearly exclusively by national laboratory scientists and their
collaborators at universities. During the 1970's and 8O's they were
increasingly turned into user facilities, meaning more collaboration, more
independent use and more competition throughout the scientific and technological
communities for using them.
Principal among the major facilities or research materials provided
with full or large support by AEC's Chemistry Programs and its successors
have been these:
The story of the short-lived National Resource for Computation in Chemistry
is probably the saddest in the annals of chemistry in AEC-ERDA-DOE.
It met two timely needs, was carefully conceived, was strenuously competed
for, and recruited its director very carefully. But after only a
year of operation, it was killed by authorities higher than Chemical Sciences.
This story was probably the original basis for the saying, "When chemists
get into trouble, they pull their wagons in a circle and shoot inward."
Accomplishments
Each Federal agency that has supported significant numbers of researchers
in chemistry has a collection of accomplishments of which to be proud.
The list for AEC's Chemistry Programs and its successors is long, but an
incomplete list of selected items shows its progression from focus on things
nuclear to things bearing on energy in general:
Discovery of many nuclear properties.
Original applications of isotopes to geochemical problems, including
proof of plate tectonics.
Neutron activation analysis.
Discovery and characterization of the hydrated electron.
Advancing chemical measurements from milliseconds to picoseconds and,
with others, femtoseconds.
Separations by ion exchange and solvent extraction
Photosynthesis: synthesis of and major research progress using
fully deuterated chlorophyll; special pair photosynthetic reaction center
and its intricacies.
Discovery of ozone-layer effects of chlorofluorcarbons.
Revolutionized understanding of coal structures.
Laser-based diagnostics of combustion chemistry and physics.
Major contributions on metal cluster behavior. ELLIOT S. PIERCE received his B.S. M.S. and
Ph.D. degrees from Yale. After a year of teaching at the University
of Massachusetts and 10 years with American Cyanamid he joined the staff
of the Air Force Office of Scientific Research. In 1961 he
moved to the Research Division of the Atomic Energy Commission, and in
1967 became Director of the Nuclear Education and Training Division.
In 1973 he became Director of the Chemical Sciences Division for AEC and
its successors, the Energy Research and Development Administration and
Department of Energy, serving concurrently during 1975-1979 as Director
of Engineering, Mathematical and Geosciences. He retired from federal
service in 1986 but remains active in the governance of the American Chemical
Society. Last Modified: September 14, 2000
This document lists some of the accomplishments
made possible by the research program over the last 20 years. It
is important to keep in mind that all of the advances listed below resulted
from the pursuit of knowledge at the most fundamental level. The
application of that knowledge to specific problems often enabled major
technological innovations. It is a characteristic of basic research that
its products often have impact on an unanticipated and broad scale.
This characteristic is illustrated in these accomplishments. They
serve as a testament to the value of open, undirected research.
Charles H. Byers, Editor, February 7,
2000
Aqueous
Diphonix: A New Ion-Exchange Resin for the Removal of Radioactive and Hazardous
Metal Ions from Solution (Mark L. Dietz)
Ion-Water
Structure in Hydrothermal Water (ClemYonker)
Center
for Green Manufacturing (Robin Rogers)
NSF
Science and Technology Center for Environmentally Responsible Carbon Dioxide
Processes (Keith Johnston)
Adsorption
Energy Distribution (Georges Guiochon)
Affinity
of a Surface Substrate for a Protein (Georges Belfort)
Single-Molecule
Diagonistics Reveal Mechanism of Chromataographic Separations (Ed Yeung)
High
Sensitivity Infrared Spectroscopy of Silica/Solution Interfaces (Joel M.
Harris)
Relaxation
Methods to Measure Sorption/Desorption Rates (Joel M. Harris)
Application
of Molecular Recognition to Capillary Scale Separations (Michael Sepaniak)
Fission
Product Separation using Room Temperature Ionic Liquids (Sheng Dai)
Improvements
in Applications orPractice
In
Situ FTIR Internal Reflection Spectroscopy (Jan Miller)
DNA
Hybridization using a New Polymer Chain Growth Method (Mary Wirth)
Commercialized
Research Results
Commercialized
Technologies
Uranium From Phosphate
Rock Processing (ORNL)
Commercialization
Of CO2-Based Green Chemistry (Hank D. Cochran)
Cleanup of High-Level
Waste Benefits from Fundamental Studies on Crown Ethers (Bruce Moyer)
Since
the promising discovery in 1967 that crown ethers could selectively bind
alkali metals, scientists have regarded these large cyclic molecules as
a possible solution to the decades-old cesium decontamination problem. Until
recently however, no compound of this type has possessed sufficient selectivity
and extraction strength. This
changed with the advent of new calixarene-crown compounds in Europe. Even
so, key gaps in fundamental knowledge stood in the way of developing a
functional industrial process. Contributions toward this end came
from ORNL. First, a soluble
calixarene-crown extractant would have to be synthesized. Techniques
discovered in basic research made possible ORNL's cesium extractant shown
here, called "BOB Calix". The
extractant is shown together with a positively charged ion of cesium (Cs+)
inside one of its cavities. As
shown more precisely in the 3-dimensional structure above, the rather precise
fit of the Cs+ ion in the cavity gives rise to the remarkable
selectivity for Cs+ ion.Making
BOB Calix function properly required understanding the molecular details
of its extraction and subsequent release of Cs+ ions.A
critical step was the use of special fluorinated alcohols that enhance
BOB Calix's extraction strength, allowing the expensive extractant to be
effective at economical concentrations.
One
of the alcohols is shown to the right. Understanding
the details of the chemical reactions taking place through mathematical
modeling of extraction data then revealed how to make the complex release
its bound Cs+. This closed
the cycle allowing the solvent to be used over and over again.
Crown Ethers for
Removing Technetium from Alkaline Waste Solutions (Bruce Moyer)
Basic Research
Reduced Cost of Uranium Production (Bruce Moyer)
In
extractions, usually this anion is exchanged for a larger anion. A
structure for a common type of extraction complex formed in such extractions
is shown in the figure. This
complex consists of the long-chain ammonium ions and two anions X-
and Y- of different sizes. The
small anion X- receives two hydrogen bonds from a pair of ammonium
ions, and the larger anion Y- receives none. In
the molybdenum problem studied at ORNL, the small anion was chloride Cl-
and the large anion had the complicated formula PMo12O403-. The
entire complex contained this large anion, three chloride ions, and six
ammonium ions. Unfortunately,
an X-ray structure of this unwieldy complex could not be obtained, but
the general structure shown at right was in fact demonstrated for the first
time on a related compound. The
latter has two tributylammonium ions, one chloride, and one tetraphenylborate. Thus,
an investigation related to a real-world problem explained a great deal
about an important class of separations.
Low Fouling Ultrafiltration
and Microfiltration Aryl Polysulfone (Georges
Belfort)
DEPA-TOPO
(ORNL)
Separation of Lanthanides
(Ames Lab)
Zirconium-Hafnium
Separation (ORNL -Ames)
The hafnium
separated from the zirconium also has important applications. The very
quality that makes hafnium a poor material for cladding is its high neutron
absorption cross section. This renders it ideal for use in nuclear reactor
control rods. Other desirable characteristics of hafnium include good ductility,
machinability, and hot water corrosion resistance. Most of the U.S. hafnium
production is used for control rods in naval reactors for nuclear powered
ships and submarines. Other uses for hafnium include additives in high-strength
materials, corrosion-resistant steels, cutting tool alloys, and optical
glass.
The Calutrons -
Isotope Separations (ORNL)
Fast Fluid Analyzer
(ORNL)
Continuous Annular
Chromatography (David DePaoli)
Emulsion Phase
Contactor (David DePaoli)
Dielectric
Filter (David DePaoli)
The
imposition of a high electric field to a granular bed of dielectric material
like titania or glass imparts remarkable filtration properties to the dielectric
bed. If a fluid phase containing nanometer or larger solid particles or
droplets in the same size range, virtually complete removal of the dispersed
phase can be accomplished.This
technology has been applied by Dow Corning in its silicone production.It
has several other applications as diversified a cleaning the smallest of
metal cutting from machine oil to the breaking of aerosol. The photos show
a simulation of the cutting oil example, where submicron particles of hematite
are trapped in glass granules.
Micelles and Microemulsions
in Supercritical Fluids (Clam Yonker)
Pioneering work at PNNL in the area of micelles and
microemulsion in supercritical fluids has led to the commercialization
of an important new cleaning technology utilizing CO2.
Patents developed under the BES projects have been licensed to Micell,
Inc. for dry cleaning applications. This new company was founded by Joe
DeSimone who has made important discoveries in the design and synthesis
of CO2 surfactants. The technology
has won numerous awards during the last 5 years. In 1999, PNNL received
the "Federal Laboratory Consortium for Technology Transfer" Award for Excellence
for technology transfer of the reverse micelle technology to Micell Inc.
PNNL's excellence in surfactant technology, their decade-long effort in
CO2
cleaning and their involvement in the Joint Association for the Advancement
of Supercritical Fluid Technology (JAAST) all played a role. In 1998, the
significance of the PNNL/MICELL combined technology earned it an R&D
100 Award from Research and Development Magazine. In 1997, the Presidential
Green Chemistry Challenge Award was presented to DeSimone and his collaborators
(including PNNL) by EPA Director Browner and Vice President Gore.
Stabilized Expanded
Bed (David DePaoli)
Products in Commerce
Aqueous Diphonix : A New Ion-Exchange Resin for the
Removal of Radioactive and Hazardous Metal Ions from Solution (Mark L.
Dietz)
Considerable effort has been devoted to the development
of ion-exchange resins capable of the selective removal of actinides from
mixed and radioactive waste solutions and of hazardous metal ions (e.g.,
Zn , Cd, Pb) from industrial waste streams. Although effective under certain
conditions, most commercially available ion-exchange resins suffer from
one or more drawbacks that limit their utility. For example, commercial
resins are typically ineffective at moderate (pH 1-4) to high (>0.1 M H+)
acidities and in the presence of high concentrations of alkali metal salts.
In addition, the rates of metal ion uptake and desorption are typically
slow. Finally, each resin is typically capable of sorbing only a few types
of metal ions from aqueous solution under a given set of conditions.
A New Generation
Of Selective Polymer Beads (Spiro Alexandratos)
Bifunctional Anion
Exchange Resin for Groundwater Cleanup (Bruce Moyer)
To
solve this problem, the researchers created the bifunctional resin they
call "BiQuat," shown in the figure below.The
secret to BiQuat is the presence of both small and large positively charged
groups within the resin.The small
groups promote fast exchange, while the large groups provide highly selective
sites.In field tests at Paducah,
BiQuat performed five-fold better than the resin used at the site.Field
tests for a similar ion, perchlorate, have shown equally impressive results.A
patent application is pending, and a commercial material is in development
by the Purolite Company, a major producer of ion-exchange resins.A
1999 Lockheed Martin Technical Accomplishment Award recognized this work.Both
applied and fundamental research continues.
Surfactants
For Dry Cleaning (Keith Johnston)
Insoluble Drug
Formulations (Keith Johnston)
Separation Methods
Technologies, Inc. (Mary Wirth)
Commercialized
Techniques
Solvent-Extraction
Research Provides Basis for Commercialization of Sensitive Analytical Methodology
(Bruce Moyer)
Sensitive Instrumentation
for Measuring Radionuclides has Revolutionized Radioanalytical Laboratories
(Bruce Moyer)
Evaporative Light
Scattering Detector (ELSD) For HPLC (Georges Guiochon)
Polymer Chain Growth
On Surfaces (Mary Wirth)
Laser-Based Detectors
For Liquid Chromatography (Ed Yeung)
Ionization Laser
Vaporization for Mass Spectrometry (Ed Yeung)
Applications of
Small Drop Generation Technology (Osman Basaran)
High-Temperature
Fiber Optic Spectroscopic Instrumentation Magnesium
Industry (Sheng Dai)
Spectroscopic Sensors
for the Aluminum Industry (Sheng Dai)
Spectroscopic Titanium
Complex Sensors For The Titanium Industry (Sheng Dai)
Research Beneficial
to Society
Beneficial Technologies
Principle of Bifunctionality
(Spiro Alexandratos)
Room Temperature
Ionic Liquids (Robin Rogers)
Synergism Changes
Course of Research on Crown Ethers for Extraction of Metal Ions (Bruce
Moyer)
From Nuclear Waste to Nuclear Medicine: Improved Chemistry
for the Production of Yttrium-90 for Medical Applications (Mark L. Dietz)
Considerable effort has recently been directed toward
the development of site-specific methods for the treatment of various forms
of cancer using radionuclides. Among the more attractive radionuclides
for such applications is yttrium-90 (Y-90). Researchers throughout the
United States have been assessing its effectiveness (as part of labeled
monoclonal antibodies) in treating lymphomas, leukemia, and ovarian, colorectal,
esophogeal, and bone cancer. Others are exploring its application to the
treatment of rheumatoid arthritis. Safe clinical use of Y-90 requires that
it be made essentially free of its parent radioisotope, strontium-90 (an
isotope known to cause bone marrow suppression), and any other elements
that could interfere with radiolabeling. Many processes for effecting the
necessary separation and purification have been described. All of them,
however, suffer from shortcomings that make an improved process desirable,
most notably, complexity, generation of yttrium in a form unsuitable for
direct antibody labeling, or a gradual fouling of the strontium-90 stock
(from which the Y-90 is obtained) by accumulation of process impurities.
SREX : A New Process for the Extraction and Recovery
of Radiostrontium from Acidic High Level Liquid Wastes (Mark L. Dietz)
Decades of nuclear weapons production have resulted
in the generation of large quantities of highly radioactive liquid wastes.
Much of this material, whose total volume is estimated to be nearly 60
million gallons, is currently stored at various USDOE sites in a series
of underground steel tanks. Because of the obvious potential environmental
and safety hazards posed by the extended storage of such waste liquids,
there has been considerable interest in the development of methods by which
the waste can be rendered suitable for safe, stable, long-term storage.
Of the options now under consideration, the most promising involves the
incorporation of the material into a glass matrix and placement of this
solidified waste deep underground in a geologic repository. Because of
the enormous expense associated with waste conversion to glass, it is desirable
to perform a preliminary separation and preconcentration of the most hazardous
radionuclides, reducing the volume of waste requiring conversion and leaving
the balance of the waste suitable for comparatively inexpensive near-surface
disposal. Among these hazardous radionuclides is Sr-90. As one of the major
heat-producers in nuclear wastes, its presence greatly complicates waste
treatment, as unless it is removed, it could become necessary to remove
a significant amount of heat from the stored solid wastes.
Beneficial Techniques
Technical Consulting
Impact of ORNL Actinide Program (Sheng Dai)
Surface Chemistry
Details Of Alkyl Carboxylate Adsorption (Jan Miller)
Flotation Of Fine
Particles In A Centrifugal Field (Jan Miller)
Filtering Protein
Solutions (Georges Belfort)
Perfectly Insulating
Ultra-thin Silica Layers Immobilized on Metal Surfaces (Jeanne E. Pemberton)
The interest in silica surface chemistry relevant to separations science
in the Pemberton group at the University of Arizona has led to the development
of a new method for the formation of extremely thin (<100 Å),
homogeneous and dense layers of silica immobilized on metal surfaces. These
layered systems could be extremely important as dielectric layers in new
ultra-small electronic and optoelectronic technologies, especially those
based on organic polymer systems (such as organic-based transistors which
are representative molecular electronic devices and organic light-emitting
diodes which are being studied for use as pixels in display devices.) As
shown in figure on the right, these unique layered structures are formed
starting with a "molecular adhesive" layer that is comprised of a single
layer of (3-mercaptopropyl)trimethoxysilane (hereafter called 3MPT) molecules
that are directly bonded to the metal surface and which provide sites for
bonding (i.e. "adhesion") of the thin silica layer on their outer edges.
The thin silica layer is then formed by spin-coating a very small quantity
of a dilute solution which contains reactive molecular precursors (molecules
called tetramethoxysilane or TMOS) to silica. These TMOS precursors react
with the 3MPT layer and with each other through a process called sol-gel
chemistry to give the final solid silica layer. Our original interest in
these systems was driven by our studies in separations chemistry; however,
these thin silica layers have been found to possess some unexpected but
quite remarkable insulating properties which have not been previously observed.
Even when these layers are extremely thin (~30 Å or in other words
approximately one-millionth the thickness of a human hair) they behave
as perfect insulators with dielectric strengths and resistances better
than or comparable to those of thermally grown silica (~10 MV/cm and >TS,
respectively), which is the material universally used as insulating layers
in virtually all microelectronics devices today. Even more noteworthy is
the fact that these film qualities are realized through a strictly room-temperature
process with no heating steps required. We believe that the unprecedented
insulating qualities of our films are due to their unique microstructure
that results from the sol-gel preparation conditions used coupled with
the spin-coating chemistry on the 3MPT-modified metal surface. Although
many other researchers have tried to fabricate truly insulating ultra-thin
films from both inorganic and organic materials, none have exhibited the
outstanding insulating characteristics of our ultra-thin silica films.
In addition to the unique electronic characteristics of these films, they
also can be modified and used as models of silica surfaces for spectroscopic
characterization of chromatographic stationary phases.
Molecularly Imprinted Ordered Nanoporous
Materials for Separation (Sheng Dai)
This
method makes use of the unique surface environment of hexagonally packed
mesopore surfaces of selected pore sizes and coats such surfaces with functional
ligands by binding to a target metal ion template (see Fig. 1).This
procedure produces much more uniform imprints that have the ideal size
and stereochemical requirements (see Fig. 2) for binding target metal ions
and has led to the preparation of mesoporous sorbents that exhibit unprecedented
binding selectivities not observed in sorbents prepared by conventional
coating methods. This development has resulted in a new class of ordered
mesoporous sorbents with molecular recognition capabilities.We
view these sorbents as solid state analogues to crown ether ligands, which
can be tailored for a specific target ion.The
simplicity of this technique should lead to a wide variety of new highly
selective sorbents, the properties of which can be optimized for many metal
ions with the proviso that they form stable coordination complexes with
a suitable bifunctional ligand containing a silane group.Furthermore,
this surface imprinting methodology should not be limited to the binding
of metal ions.If complexes or molecules
can be formed between targeted organic molecules and functional groups
containing a silane group, application of the above methodology should
lead to the synthesis of sorbents, which exhibit molecular recognition
of organic molecules.The design
principles illustrated by these results highlight opportunities for application
in such areas as selective sorption, chemical sensing, and catalysis offered
by imprint/coated mesoporous materials of special status as a timely and
urgent communication.
Fig. 2 Schematic representation of the difference between the cavities
generated by conventional coating (left) and imprint coating (right).
Paradigm-changing
understanding
Studies to design, synthesize, and evaluate cyclic organicligands have
produced compounds that selectively complex metal salts and solubilize
them in organic solvents. These cyclic organic ligands
are applicable to procedures for separating metal salts by differential
distributions between water and organic solvents containing the ligands.
The organic compounds possess charged cavities that match the sizes and
charges of metal ions they are designed to encapsulate. Compounds
that will differentiate between actinides, lanthanides and other products
of spent reactor fuels are being sought.” (The underlines are his.)
Solvation In Supercritical
Fluid Systems, A Molecular View (Frank V. Bright)
Expanding the paradigm on membranes. (William
Koros)
Recently, research supported at the University of Texas has demonstrated
a fundamentally based approach to expand the use of membranes to
other important feed streams such as natural gases, petrochemical gases,
and even liquids.Early tests show
that the method, based on selective crosslinking of polymers, can be practically
implemented.This development has
the potential to double or triple the potential application of membranes
to replace more energy intensive methods.This
should have a huge impact on both membrane sales and the more effective
use of natural gas that currently cannot be economically processed by traditional
methods.This is especially useful
for offshore and isolated sites.
Center
for Green Manufacturing (Robin Rogers)
The primary
motivation of the multiphase separations research is an understanding of
the behavior of fluid-fluid and solid-fluid flows and how they are affected
by the application of external fields, including electric, magnetic, and
gravitational. Of particular
interest is the behavior of interfaces in applied field situations.In
the latter area, some of the primary contributions of the past decade have
been made at Oak Ridge.Some of
the specific contributions include:
Droplets
and bubbles are at the basis of many separations processes and as such
are the fundamental limitations of such processes.Understanding
what leads to smaller, more turbulent droplets is a primary consideration,
as are the dynamics of dispersion and coalescence.Oak
Ridge workers have explored experimentally the formation of
drops in fields, and their publications have greatly extended the understanding
of such areas as formation in fields, oscillation dynamics, and hysteresis.
NSF Science and
Technology Center for Environmentally Responsible Carbon Dioxide Processes
(Keith Johnston)
Adsorption Energy
Distribution (Georges Guiochon)
Affinity of a Surface
Substrate for a Protein (Georges Belfort)
To understand the mechanisms governing chromatographic separation of
molecules by liquid chromatography, it is critical to know the structure
of adsorbates at a silica/solution interface and the chemical interactions
that are responsible for retention on the surface. Under DOE support,
we have developed a vibrational spectroscopy that is allowing us to acquire
in situ infrared absorption spectra of monolayers on the surfaces of silica
in contact with mobile-phase liquids. We have captured a thin layer
of colloidal silica particles onto an internal-reflection element (zinc
selenide or germanium) to provide a high area surface for internal-reflection
infrared measurements of molecules at silica/solution interfaces.
Unlike planar silicon substrates, this approach opens up the spectral window
to the entire mid-infrared range; it also provides a significant (nearly
1000-fold) increase in surface area for sensitive detection of sub-monolayer
species. We used this method to study the adsorption of polar adsorbates
to silica from nonpolar solvents. The vibrational spectroscopy has shown
that previous models developed to explain nonlinear isotherm behavior are
incorrect, and that the nonlinearity derives from site heterogeneity on
the silica surface. We can report vibrational spectra both from the
adsorbate as well as from sites on the surface. These provide information
that help in the development of a model for retention. Competitive
adsorption was also investigated, which is important for understanding
solute displacement and elution programming in normal-phase liquid chromatography.
Most of our understanding of chromatographic processes has been inferred
from solute retention measurements. These measurements do not generally
provide information about the role of sorption and desorption kinetics
on retention equilibria. With DOE support, we pioneered a temperature-jump
relaxation technique to monitor reversible kinetics at the chromatographic
liquid/solid interfaces. A Joule-discharge apparatus was used to
heat a packed bed of chromatographic silica on microsecond time scales.
We investigated the sorption/desorption relaxation kinetics for fluorescent
probes at a C18-modified silica surface. On a 100 ms
time scale, a biexponential relaxation was detected for ionic solutes,
where the slow rate increased as retention of the solute was increased
(by changes in mobile phase composition). This behavior suggested
that sorption kinetics were controlling the relaxation rate; a linear dependence
of the rate on the concentration of the probe in the mobile phase verified
this hypothesis. The results showed further that the sorption rate
of ionic probes is slower than diffusion-limited and exhibits significant
influence over the sorption equilibrium constant. The sorption rates
of two neutral probes, however, were indistinguishable from a diffusion
limit indicating a negligible barrier to sorption.
A similar study of adsorption kinetics onto a C1-derivatized silica surface
showed that a slow relaxation rate arose from the adsorption of ionic solutes
from solution. These results helped us understand the origins of
the two steps for sorption onto longer chain ligands on silica surfaces.
For adsorption of neutral probes onto a C1-surface, no barrier could be
detected. To compare the response of an intermediate chain-length
surface, we measured adsorption/desorption relaxation kinetics for an ionic
fluorescent probe at C4-derivatized silica. A biexponential relaxation
was detected having comparable rates that linearly increase as solute concentration;
this behavior shows that adsorption kinetics on the intermediate chain
length interface are different from the kinetics on both C1 and C18 surface.
The relaxation rate of a neutral probe was also measurable in our experiments,
which indicate the kinetic barrier to sorption cannot be neglected as in
C1 and C18 cases. These results show that retention of molecules
on surfaces having alkyl-chain length arise from different underlying kinetic
mechanisms.
Application of
Molecular Recognition to Capillary Scale Separations (Michael Sepaniak)
Fission Product
Separation using Room Temperature Ionic Liquids (Sheng Dai)
Ion-Water Structure in
Hydrothermal Water (Clem Yonker)
Supercritical water has important potential applications in (1) oxidative
destruction of hazardous waste, (2) organic synthesis and oxidation reactions,
and (3) salt separation and solubility. Coordination structure and redox
chemistry in supercritical water are also of high interest to the area
of geochemistry and corrosion. Due to the difficulty of experimentally
probing this extreme solvent environment there is a severe lack of fundamental
structural information. In ongoing studies at PNNL, scientists are using
XAFS (X-ray Absorption Fine Structure) to study the structure of supercritical
water at the Advanced Photon Source at Argonne National Laboratory. In
the first studies of this kind it has been shown that XAFS is a powerful
method to determine the local solvent environment around an ion in terms
of the number of nearest solvent neighbors and the hydration distance.
("An XAFS Study of Strontium Ions and Krypton in Supercritical Water.",
Pfund, D.M.; Darab, J.G.; Fulton, J.L.; Ma, Y., J. Phys. Chem. 1994, (98):13102-13107.)(
"The ion pairing and hydration structure of Ni2+ in supercritical
water at 425°C determined by x-ray absorption fine structure and molecular
dynamics studies." Wallen, S.L.; Palmer, B.J.; Fulton, J.L., J. Chem. Phys.
1998, (108):4039-4046.)
Improvements in
Applications or Practice
In Situ FTIR Internal
Reflection Spectroscopy (Jan Miller)
DNA Hybridization
using a New Polymer Chain Growth Method (Mary Wirth)
Packing Density
Homogeneity in Chromatographic Columns (Georges Guiochon)
See, e. g.:
Consolidation of Particles Beds and Packing of Chromatographic
Columns. Georges Guiochon, Tivadar Farkas, Hong Guan - Sajonz, Joon-Ho
Koh, Matilal Sarker, Brett J. Stanley and Tong Yun. Journal of Chromatography
A, 762 (1997) 83-88.
Flotation of
Mineral Particles from Saturated Brines (Jan Miller)
Analysis of the
Long Range Hydrophobic Attractive Force (Jan Miller)
Emulsification
of Water and CO2 with Surfactants (Keith Johnston)
Program for Modeling
Liquid-Liquid Extraction Data (Bruce Moyer)
As
a research tool, the program thus allows researchers to gain a deep understanding
of a system and allows prediction of behavior over a wide range of conditions,
even those that have not been tested.This
understanding has in turn helped make it possible to develop both analytical
and process applications of crown ethers.For
example, an understanding of the model below allowed ORNL researchers to
find suitable process conditions for cesium extraction from nuclear waste.
Exploration of
Fluorescence Lifetime Measurements (Linda McGown)
Viscous Fluid Overturn
during Rupture (Osman Basaran)
Satellite Drop
Elimination (Osman Basaran)
High Pressure NMR (Clem Yonker)
Since the mid 90's, work at PNNL has focused on the
investigation of supercritical fluid solutions using high-pressure NMR.
There are numerous experimental techniques that have been used to investigate
supercritical fluids. These range from FTIR, UV-Visible, fluorescence,
ESR, and x-ray spectroscopies. NMR is a technique that has seen limited
application to supercritical fluid solvents due to the specialized need
for the design of a high pressure, non-magnetic probe and its associated
electronics. There have been different successful solutions to a functioning
high pressure NMR probe ("A new apparatus for the convenient measurement
of NMR spectra in high-pressure liquids", Yonker, C.R.; Zemanian, T.S.;
Wallen, S.L.; Linehan, J.C.; Franz, J.A., J Magn Res A 1995, (113):102-107)
and each of these probe designs has its own strengths and weaknesses. Overall,
NMR is an information rich spectroscopic technique, which can describe
the solvent environment about a solute molecule, determine self-diffusion
coefficients, ascertain molecular structure, measure hydrogen bonding in
solution, and describe molecular clustering as a function of density. NMR
can provide important molecular level information about the density dependence
of rotational and translational dynamics in supercritical fluid solutions.
Similarly, high-pressure kinetics and chemical equilibria can be investigated
by the use of NMR.
Conclusions
References
Appendix A: Contributors
Spiro D. Alexandratos
Osman
Basaran
Georges Belfort
Frank V. Bright
Hank D. Cochran
Sheng Dai
David DePaoli
Mark
L. Dietz
Georges
Guiochon
Joel
M. Harris
University of Utah
315 South 1400 East
Salt Lake City, UT 84112 -0850
Phone: 801-581 - 3585
Fax: 801-581-8433
harrisj@chemistry.chem.utah.edu
Keith P. Johnston
William J. Koros
Linda B. McGown
Jan D. Miller
Bruce A. Moyer
Robin D. Rogers
Michael J. Sepaniak
Mary J. Wirth,
Edward S. Yeung
Dr. Clement R. Yonker
Appendix B: Request
Letter
(The following is from the Proceedings of a Symposium on the Early
History of Chemistry at the Research Support Agencies, held in Washington,
DC, August 30, 1990.)
The 1960's
"In science, the excellent is not just better than the ordinary; it
is almost all that matters."
Nuclear Chemistry was moved from Chemistry to a newly created
Nuclear Sciences Division run by physicists.
In 1975 AEC was divided in two, one part moving into the new Energy Research
and Development Administration. ERDA took over the AEC's, production
and military programs, in the process redirecting programs and initiating
more complex administrative procedures.
From radiation chemistry to solar-related photochemistry.
During the 1950's, 60's and 70's, Chemistry Program and its successors
relied on universities for about 1/3 of its performers, who, on a part-time
basis, received about 1/4 of the funds. In the late 1970's, with
the advent of the Department of Energy, those fractions rose to about 1/2
and 1/3, respectively. At the same time there began the process of increasing
collaborations among national laboratories, universities, and industry.
Argonne's Atomic Spectroscopic Facility.
Argonne's 4.5-MV Dynamitron Accelerator.
Argonne's Linear Electron Accelerator.
Argonne's Premium Coal Sample Program.
Berkeley's National Resource for Computation in Chemistry.
Brookhaven's High Flux Beam Reactor.
Brookhaven's National Synchrotron Light Source.
Kansas State University's Atomic Physics Accelerators.
Notre Dame University's Electron LINAC,
Oak Ridge's Calutrons (isotope separators).
Oak Ridge's EN-Tandem Van de Graaff Accelerator.
Oak Ridge's High Flux Isotope Reactor.
Oak Ridge's Transuranium Processing Facility.
Pacific Northwest Laboratory's Molecular Sciences and
Environmental Research Center
Sandia's Combustion Research Facility.
Stanford's Synchrotron Radiation Laboratory.
The NRCC
Transplutonium elements -- discovery and characterization.
There is another accomplishment, made not in any laboratory.
DOE's Division of Chemical Sciences made it possible for the National Research
Council's (NRC's) Committee on Chemical Sciences (now the Board on Chemical
Sciences and Technology) come into existence. It functioned for its
first two years with support from only DOE, until other agencies joined
in. Ably guided by Bill Spindel, it served as an improved force for
chemical interests in the NRC. Among the Board's stellar studies
is the highly respected Pimentel Report. For the record, although
titles changed during the several reorganizations, the heads of the basic
research programs in chemistry at AEC-ERDA-DOE were:
DANIEL R. MILLER received his B.S. and M.S.
degrees from the University of Wisconsin and his Ph.D. from the University
of California at Berkeley. He then accepted an appointment as Assistant
Professor of Chemistry and Nuclear Studies at Cornell University,
In 1951 he joined the staff of the Atomic Energy Commissioner’s Division
of Research, rising to become Assistant Director for Chemistry Programs
and then Deputy Director of the Division, carrying on with corresponding
duties in the successor organizations of ERDA and DOE. He retired
in 1979 but as a consultant continues to assist in the administration of
the DOE Small Business Innovation Research Programs.
Spofford G. English 1947-1958
Daniel R. Miller 1958-1961
Alexander R. Van Dyken 1961-1973
Elliot S. Pierce 1973-1986
Robert Marianelli 1986-1998
(Current Staff of The Chemical Sciences, Geosciences, and Biosciences
Division can be found at
http://www.sc.doe.gov/production/bes/chm/Staff/staff.html)