Materials under extreme conditions: panel membersPlenary Closing Session October 14, 2010
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A guide to improve performances
New stripping strategy
What basic thermodynamic and kinetic properties of amidoxime complexation processes?
Synthesis of model compounds
Spectroscopic and structural characterization
Plenary Closing Session October 14, 2010
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Synthesis of simple analogs
Solution studies to characterize binding affinity, selectivity and kinetics of binding.
Model potential species using electronic structure calculations
Uranium complexation in AO polymers is not understood.
What is the main uranyl binding motif in these materials?
Fundamental understand of why these polymers work.
Provide a basis to design improved adsorbents based on the amidoxime functional group.
Improved adsorbent performance will result in significant cost reduction
5 - 10 years
Plenary Closing Session October 14, 2010
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Refine technology (mooring design, process optimization)
Carry out tests to optimize system design for present chemistry
Document the intersection of appropriate temperatures, appropriate currents and legally permissible sites
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Plenary Closing Session October 14, 2010
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New composite materials built from nanoporous components to enhance extractant transport, diffusion, and binding
Can stable polymeric or inorganic supports with significantly enhanced surface areas and mass transport properties be developed to increase both capacity and efficiency of uranyl adsorption under seawater conditions?
More efficient extraction
Higher binding capacity
Increase system durability
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Plenary Closing Session October 14, 2010
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Identify donor groups (phosphate, amide, imine, hydroxamate, etc.)
Computer-aided design of candidate ligand structures that can be incorporated in adsorbents
Synthesis of compounds
Solution studies to characterize binding affinity, selectivity and kinetics of binding.
Develop improved ligands for removal of uranyl cation from seawater:
• increased affinity and selectivity
How variation in donor groups influences uranyl binding – cooperativity effects
Improved adsorbent performance will result in significant cost reduction
5 - 10 years
Plenary Closing Session October 14, 2010
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To study fundamental uranium complexation experimentally and to model these processes computationally
What are the unique thermodynamic and kinetic properties of polymer adsorbents associated with uranyl sorption processes?
Better understanding of uranium coordination chemistry
Better methodologies for computing metal-ligand coordination thermodynamics
Development of chelators with better binding characteristics
More efficient uranium extraction
Plenary Closing Session October 14, 2010
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Develop New functional group incorporation, grafting, and attachment chemistries
Are there new synthetic techniques for incorporation of a high density of binding sites into adsorbent supports?
Higher binding capacity
More efficient extraction
New surface chemistry
Resource Extraction:
Plenary Closing Session October 14, 2010
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Develop new nanostructured materials as novel sorbents for selective uranium binding
Can recent breakthroughs in nanotechnology be used to make advanced adsorbents for recovery of uranium from seawater?
Enhanced extractant transport and diffusion
New nanoscience and nanotechnology
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Plenary Closing Session October 14, 2010
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High capital cost and availability of high energy radiation.
Can reasonable degree of grafting be achieved using lower energy radiation?
Radical decay between irradiation and grafting.
This approach opens door for widespread research in uranium absorption.
Wide range of chemistries (e.g. thiol ‘click’, living radical) available.
Primarily surface modification which could lead to more efficient adsorption and preserved fiber integrity, durability, and longevity.
This approach opens door for widespread research in uranium absorption.
Simultaneous radical generation and grafting.
Initial evaluation of effectiveness within 3 years.
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Plenary Closing Session October 14, 2010
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To better understand uranium coordination chemistry to identify best stripping methods
Is any better and cleaner stripping process or recycling strategy to efficiently recycle adsorbents?
New knowledge about uranium chemistry
Improved product separation and recovery techniques
Less secondary wastes
Selective stripping for better uranium purity and for recovery of other valuable co-products
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Plenary Closing Session October 14, 2010
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Recognition of the [UO2 (CO3)3]2- dianion
Evaluate speciation as a function of concentration up to the lower limit of the technique and then extrapolate to the seawater concentration.
De novo structure-based design and high throughput screening to identify host structures that complement the targeted species.
Speciation of uranyl ion at seawater concentrations
Achieving significant binding affinity for an anionic metal complex
Better understanding of uranyl speciation in seawater
Development of characterization techniques applicable to extremely low concentrations and complex media.
Demonstrate the feasibility of outer-sphere host-guest complexation
Significant improvement of selectivity for uranyl over competing transition metals
5 - 10 years
Plenary Closing Session October 14, 2010
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Impact of biofouling on extraction technologies
Need for actual field testing, or raw seawater studies in controlled tanks
New antifouling strategies
System design concerns to ameliorate fouling
3-5 years for early impact
Determine potential impact biofouling may have on extraction technologies:
Interference of molecular foulants (peptides, polysaccharides, nucleic acids) on nanomaterials
Impact of fouling coatings on U-recovery process (calcite or silica oozes)
Potential for organisms to degrade sorbants
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Plenary Closing Session October 14, 2010
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Site Selection and Permitting for Sorbent fields
Lab tank testing of U-saturated sorbant materials with model organisms. Test uptake potential, leaching, grazing
Industry cannot begin to write an environmental impact statement without conducting basic research to understand issues such as:
Potential toxicity and leaching of sorbant chem
Potential entry of concentrated U into food web
Durability of material under field conditions
Model and test the impact of design local ocean current, benthic ecology, marine mammals, fish
May result in the selection or rejection of certain chemistries.
Empirical testing will provide valuable data about bioaccumulation of U in primary producers through higher order predators
Impacts system design and location considerations
What’s the timescale in which that impact may be felt?
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Plenary Closing Session October 14, 2010
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Consider site selection issues for marine hydrokinetic power
Will impact ability to conduct field tests and to engage industry– no industry investment likely if no clear path to approval
Will impact site selection and feasibility studies– may never be able to leave the laboratory
Minimum of 3-5 years
Policy concern: begin dialogue to determine who has oversight for site selection and environmental impact statements (EIS)
State, EPA, NOAA, Coast Guard, Navy, DOE, etc
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Plenary Closing Session October 14, 2010
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Cost analysis of tying U-extraction to desalination
Full analysis of water technologies, need, new and existing plant expansion, implementation forecasts
Model extraction potential for various desal technologies (RO, MSF, emerging methods)
Model flow dynamics (shorter residence time on materials
Less environmental impact and lower permitting barriers
Use of enriched brines at elevated temperatures may improve extraction efficiency for some ligand materials
Fewer complications: no field deployment and recovery
Value added for another industry
Desalination will grow as an industry– Water wars in the west coast are worsening, demand is growing, and CA cannot continue to drain the Colorado River. Florida’s aquifers are not meeting demand. Pumping costs are not a factor for U extraction- the water is the primary commodity and will drive the creation of the pump facility. The waste flow is an untapped byproduct concentrated brine at an elevated temperature.
Need to forecast the growth of desal in US and model extraction potential from various desal technologies (brine types). U extraction (and other minerals) becomes added value to desal facility
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Plenary Closing Session October 14, 2010
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Phage display, clone and subclone active sites from chelators, metaloproteins, reductases
Molecular modeling and synthetic biological design
Clone and mass-express ligands
Low cost, green fabrication
New classes of ligands
Minimum of 3-5 years
Explore the use of biogenic ligands (e.g. metalloproteins, U-reductase, peptide aptamers) for U extraction; these offer the potential for lower cost “green” fabrication and easier recovery of the extracted U (partial denaturation using mild heat, salt wash, or pH change)
Explore efficiency, stability, and cost
Compare with synthetic ligands for same parameters
Explore best substrates and attachment methods