Strategic Design and Optimization of Inorganic Sorbents for Cesium, Strontium and Actinides

It has been determined that poorly crystalline CST and SNT prepared at low temperature (100-150 C) exhibit much faster kinetics in uptake of Sr2+. In-situ X-ray studies has shown that SNT is a precursor phase to the formation of CST. It is possible to form mixtures of CST and SNT in a single reactant mix by control of temperature and time of reaction. It has been found that addition of a small amount of Cs+ to the reactant mix for the preparation of Nb-CST allows formation of the crystals in one day rather than ten days at 200 C. These discoveries suggest that a proper mix of sorbents (SNT, CST, Nb-CST) can be made easily at low cost that would remove all the HLW at the Savannah River site with a single in-tank procedure. The basic science goal in this project is to identify structure/affinity relationships for selected radionuclides and existing sorbents. The research will then apply this knowledge to the design and synthesis of sorbents that will exhibit increased cesium, strontium and actinide removal. The target problem focuses on the treatment of high-level nuclear wastes. The general approach can likewise be applied to non-radioactive separations

Strategic Design and Optimization of Inorganic Sorbents for Cesium, Strontium and Actinides

The basic science goal in this project identifies structure/affinity relationships for selected radionuclides and existing sorbents. The task will apply this knowledge to the design and synthesis of new sorbents that will exhibit increased cesium, strontium and actinide removal. The target problem focuses on the treatment of high-level nuclear wastes. The general approach can likewise be applied to non-radioactive separations

Hydrothermal synthesis and structural characterization of ammonium ion-templated lanthanide(III) carboxylate-phosphonates

Using N (phosphonomethyl)iminodiacetic acid (H4PMIDA), as a complexing agent, two new complexes, (NH4)La(PMIDA)(H2O)•H2O, 1 and (NH4)Yb(PMIDA), 2 have been synthesized hydrothermally. In both compounds, the metal ions are trapped in a three five-membered chelate rings by the chelating PMIDA anions giving a bi-capped trigonal prism LaO8N and capped trigonal prism YbO6N geometries for 1 and 2, respectively. The structure of 1 consists of La(PMIDA)(H2O) chelating units, linked together by the phosphonate oxygen atoms O1 and O3 to form a double chain along the c-axis. The double chains are then connected together by the bridging phosphonate oxygen O2 to form a 2D layered structure with alternating 4- and 8-membered apertures.The structure of 2 consists Yb(PMIDA) chelating units, which are connected by alternating bridging carboxylate and phosphonate groups along the [010] direction forming chains with a corrugated pattern. The third phosphonate oxygen bridges the chains together along the [001] direction to build the two-dimensional layer with 4 and 6 membered apertures in the bc plane. Under excitation of 330nm, compound 2 shows a broad emission band at λmax = 460nm, This emission is essentially in the blue luminescent region, which corresponds to ligand centered fluorescence

Final Report for Environmental Management Science Program - Strategic Design and Optimization of Inorganic Sorbents for Cesium, Strontium and Actinides: Activities at the University of Notre Dame

The basic science goal in this project identifies structure/affinity relationships for selected radionuclides and existing sorbents. The task will apply this knowledge to the design and synthesis of new sorbents that will exhibit increased cesium, strontium and actinide removal. The target problem focuses on the treatment of high-level nuclear wastes. The general approach can likewise be applied to non-radioactive separations. The project involves a collaboration among four organizations, with each focused on a different aspect of the problem. This document is the final report on the three years of activities conducted at the University of Notre Dame, where the research focus was on the use of molecular modeling to understand ion exchange selectivity in titanosilicates and polyoxoniobate materials

Evolution, and functional analysis of Natural Resistance-Associated Macrophage proteins (NRAMPs) from Theobroma cacao and their role in cadmium accumulation

The presence of the toxic metal cadmium (Cd2+) in certain foodstuffs is recognised as a global problem, and there is increasing legislative pressure to reduce the content of Cd in food. The present study was conducted on cacao (Theobroma cacao), the source of chocolate, and one of the crops known to accumulate Cd in certain conditions. There are a range of possible genetic and agronomic methods being tested as a route to such reduction. As part of a gene-based approach, we focused on the Natural Resistance-Associated Macrophage Proteins (NRAMPS), a family of proton/metal transporter proteins that are evolutionarily conserved across all species from bacteria to humans. The plant NRAMP gene family are of particular importance as they are responsible for uptake of the nutritionally vital divalent cations Fe2+, Mn2+, Zn2+, as well as Cd2+. We identified the five NRAMP genes in cacao, sequenced these genes and studied their expression in various organs. We then confirmed the expression patterns in response to variation in nutrient cation availability and addition of Cd2+. Functional analysis by expression in yeast provided evidence that NRAMP5 encoded a protein capable of Cd2+ transport, and suggested this gene as a target for genetic selection/modification

Redetermination of bis(2-amino-3-hydroxy-1-phenylpropanolato-κ 2 N , O 1 )(ethylenediamine-κ 2 N , N ′)cobalt(III) iodide monohydrate

New data for the title complex, [Co(C9,H12NO 2)2(C2H8N2)]I-H 2O, allow the modelling of previously unresolved disorder [Wardeska et al. (1979). Inorg. Chem. 18, 1641-1648] in the ethylenediamine ligand coordinated to the octahedral cation

Modified zirconium phosphates

A process for modifying various inorganic compounds defined by the formula: M(OH)z (HQO4)2 -z/2.xH2 Owherein M is a metal ion selected from Groups IVA and IVB of the Periodic Table of Elements, Q is an anion selected from Groups VA and VIB of the Periodic Table of Elements, z is any value from 0 to 2 and x is a number of from 0 to 8, by replacing a hydrogen in the inorganic compound with a metal cation. Suitable cations include those elements selected from Groups IA, IIA, IIIA, IVA, IB, IIB, IIIB including the lanthanide and activide series, IVB, VB, VIB, VIIB and VIII of the Periodic Table of Elements and ammonium. Thereafter, elevation of the temperature causes modification of the crystalline structure of the exchanged compound and provides various novel crystalline phases. Substitution of dissimilar metal cations for those present in the heat modified structure, with or without subsequent washing with acid, or washing out of the original metal cations, creates still other crystalline phases.U

Pillaring of layered compounds

A process is disclosed for pillaring layered materials which do not swell appreciably in water. The process comprises first intercalating an amine or other neutral molecule such as an amide or dimethyl sulfoxide between the layers of the material to be pillared. This allows the subsequent incorporation of inorganic pillars which are more temperature stable than the intercalated amine.U

Modified zirconium phosphates

A process for modifying various inorganic compounds defined by the formula: M(OH)z (HQO4)2 -z/2.xH2 Owherein M is a metal ion selected from Groups IVA and IVB of the Periodic Table of Elements, Q is an anion selected from Groups VA and VIB of the Periodic Table of Elements, z is any value from 0 to 2 and x is a number of from 0 to 8, by replacing a hydrogen in the inorganic compound with a metal cation. Suitable cations include those elements selected from Groups IA, IIA, IIIA, IVA, IB, IIB, IIIB including the lanthanide and activide series, IVB, VB, VIB, VIIB and VIII of the Periodic Table of Elements and ammonium. Thereafter, elevation of the temperature causes modification of the crystalline structure of the exchanged compound and provides various novel crystalline phases. Substitution of dissimilar metal cations for those present in the heat modified structure, with or without subsequent washing with acid, or washing out of the original metal cations, creates still other crystalline phases.U