Selective capture of radionuclides (U, Pu, Th, Am and Co) using functional nanoporous sorbents.

This work evaluated sorbent materials created from nanoporous silica self-assembled with monolayer (SAMMS) of hydroxypyridinone derivatives (1,2-HOPO, 3,2-HOPO, 3,4-HOPO), acetamide phosphonate (Ac-Phos), glycine derivatives (IDAA, DE4A, ED3A), and thiol (SH) for capturing of actinides and transition metal cobalt. In filtered seawater doped with competing metals (Cr, Mn, Fe, Co, Cu, Zn, Se, Mo) at levels encountered in environmental or physiological samples, 3,4-HOPO-SAMMS was best at capturing uranium (U(VI)) from pH 2-8, Ac-Phos and 1,2-HOPO-SAMMS sorbents were best at pH < 2. 3,4-HOPO-SAMMS effectively captured thorium (Th(IV)) and plutonium (Pu(IV)) from pH 2-8, and americium (Am(III)) from pH 5-8.

Improved deposition and deprotection of silane tethered 3,4 hydroxypyridinone (HOPO) ligands on functionalized nanoporous silica.

An improved synthesis of a 3,4 hydroxypyridinone (HOPO) functionalized mesoporous silica is described. Higher 3,4-HOPO monolayer ligand loadings have been achieved, resulting in better performance. Performance improvements were demonstrated with the capture of U(VI) from human blood, plasma and filtered river water.

Functionalized nanoporous silica for the removal of heavy metals from biological systems: adsorption and application.

Surface-functionalized nanoporous silica, often referred to as self-assembled monolayers on mesoporous supports (SAMMS), has previously demonstrated the ability to serve as very effective heavy metal sorbents in a range of aquatic and environmental systems, suggesting that they may be advantageously utilized for biomedical applications such as chelation therapy. Herein we evaluate surface chemistries for heavy metal capture from biological fluids, various facets of the materials' biocompatibility, and the suitability of these materials as potential therapeutics. Of the materials tested, thiol-functionalized SAMMS proved most capable of removing selected heavy metals from biological solutions (i.

Functional sorbents for selective capture of plutonium, americium, uranium, and thorium in blood.

Self-assembled monolayer on mesoporous supports (SAMMS) are hybrid materials created from attachment of organic moieties onto very high surface area mesoporous silica. SAMMS with surface chemistries including three isomers of hydroxypyridinone, diphosphonic acid, acetamide phosphonic acid, glycinyl urea, and diethylenetriamine pentaacetate (DTPA) analog were evaluated for chelation of actinides ((239)Pu, (241)Am, uranium, thorium) from blood. Direct blood decorporation using sorbents does not have the toxicity or renal challenges associated with traditional chelation therapy and may have potential applications for critical exposure cases, reduction of nonspecific dose during actinide radiotherapy, and for sorbent hemoperfusion in renal insufficient patients, whose kidneys clear radionuclides at a very slow rate.

Selective capture of cesium and thallium from natural waters and simulated wastes with copper ferrocyanide functionalized mesoporous silica.

Copper(II) ferrocyanide on mesoporous silica (FC-Cu-EDA-SAMMS) has been evaluated against iron(III) hexacyanoferrate(II) (insoluble Prussian Blue) for removing cesium (Cs(+)) and thallium (Tl(+)) from natural waters and simulated acidic and alkaline wastes. From pH 0.1-7.

Phosphate removal by anion binding on functionalized nanoporous sorbents.

Phosphate was captured from aqueous solutions by cationic metal-EDA complexes anchored inside mesoporous silica MCM-41 supports (Cu(II)-EDA-SAMMS and Fe(III)-EDA-SAMMS). Fe-EDA-SAMMS was more effective at capturing phosphate than the Cu-EDA-SAMMS and was further studied for matrix effects (e.g.

Selective removal of lanthanides from natural waters, acidic streams and dialysate.

The increased demand for the lanthanides in commercial products result in increased production of lanthanide containing ores, which increases public exposure to the lanthanides, both from various commercial products and from production wastes/effluents. This work investigates lanthanide (La, Ce, Pr, Nd, Eu, Gd and Lu) binding properties of self-assembled monolayers on mesoporous silica supports (SAMMS), that were functionalized with diphosphonic acid (DiPhos), acetamide phosphonic acid (AcPhos), propionamide phosphonic acid (Prop-Phos), and 1-hydroxy-2-pyridinone (1,2-HOPO), from natural waters (river, ground and sea waters), acid solutions (to mimic certain industrial process streams), and dialysate. The affinity, capacity, and kinetics of the lanthanide sorption, as well as regenerability of SAMMS materials were investigated.

Effect of the ligand shell composition on the dispersibility and transport of gold nanocrystals in near-critical solvents.

The development of more efficient and environmentally benign methods for the synthesis and manipulation of nanomaterials has been a major focus of research among the scientific community. Supercritical (ScFs) and near-critical fluids (NcFs) offer numerous advantages over conventional solvents for these purposes. Among them, ScFs and NcFs offer dramatic reductions in the volume of organic waste typically generated during advanced material processes with the feasibility of changing a number of physicochemical properties by discrete variations in solvent pressure or temperature.

Advancements toward the greener processing of engineered nanomaterials--effect of core size on the dispersibility and transport of gold nanocrystals in near-critical solvents.

The ability to process and purify engineered nanomaterials using near critical or supercritical fluids (NcFs or ScFs) has enormous potential for the application at various stages of the development of green nanomaterials. The dispersibility of octanethiol-stabilized gold nanocrystals of different core sizes is explored, which were chosen to serve as model nanomaterials of general interest in compressed ethane and propane over a wide range of fluid conditions. Both solvents have enormous potential for the environmentally benign processing and transport of engineered nanomaterials due to their nominal toxicity and high degree of tunability and processability that can essentially eliminate solvent waste.

A simple method for the prevention of non-specific adsorption by nanocrystals onto surfaces.

In this work we introduce an efficient method for averting non-specific adsorption of various nanoparticles to typical oxide surfaces, such as glass, quartz, and sapphire, through the attachment of a fluorinated self-assembled monolayer (SAM) that minimizes the interactions between stabilized nanoparticles and these surfaces. This surface treatment is shown to be effective for a variety of nanoparticles in a range of solvent systems. As a result, monitoring and characterization of nanoparticles and their surface chemistry is allowed, while simultaneously preventing loss of expensive nanomaterials to the various surfaces inherent in laboratory apparatus.

Removal of heavy metals from aqueous systems with thiol functionalized superparamagnetic nanoparticles.

We have shown that superparamagnetic iron oxide (Fe3O4) nanoparticles with a surface functionalization of dimercaptosuccinic acid (DMSA) are an effective sorbent material for toxic soft metals such as Hg, Ag, Pb, Cd, and Tl, which effectively bind to the DMSA ligands and for As, which binds to the iron oxide lattices. The nanoparticles are highly dispersible and stable in solutions, have a large surface area (114 m2/g), and have a high functional group content (1.8 mmol thiols/g).

An unprecedented mode of ligation for a bridged amido-cyclopentadienide (constrained geometry) ligand; pi-olefinic interactions with gallium and indium.

The surprising reaction of GaCl3 or InBr3 with the di-Grignard reagent [Me2Si(C5Me4)(N-t-Bu)](MgCl)2 x THF results in salts of the bimetallic anions of composition [X3M[C5Me4(N-t-Bu)]MX2]- (M = Ga, X = Cl; M = In; X = Br) in which the MX2 moiety undergoes an eta2-interaction with one of the double bonds of the localized cyclopentadienide ring.

The contrasting behaviour of bridged amido-cyclopentadienyl (constrained geometry) group 15 chlorides and cations derived therefrom.

The first group 15 amido-cyclopentadienyl (constrained geometry) cations have been prepared and structurally characterized; the structure of the stibenium cation is different from those of the corresponding phosphenium and arsenium cations.