First-Principles Integrated Adsorption Modeling for Selective Capture of Uranium from Seawater by Polyamidoxime Sorbent Materials.

Nuclear power is a relatively carbon-free energy source that has the capacity to be utilized today in an effort to stem the tides of global warming. The growing demand for nuclear energy, however, could put significant strain on our uranium ore resources, and the mining activities utilized to extract that ore can leave behind long-term environmental damage. A potential solution to enhance the supply of uranium fuel is to recover uranium from seawater using amidoximated adsorbent fibers.

Amidoxime Polymers for Uranium Adsorption: Influence of Comonomers and Temperature.

Recovering uranium from seawater has been the subject of many studies for decades, and has recently seen significant progress in materials development since the U.S. Department of Energy (DOE) has become involved.

Iron-complexed adsorptive membrane for As(V) species in water.

Selective preconcentration of a target analyte in the solid phase is an effective route not only to enhance detection limit of the conventional analytical method but also for elimination of interfering matrix. An adsorptive membrane was developed for selective preconcentration and quantification of ultra-trace (ppb) amounts of As(V) present in a variety of aqueous samples. The precursor membrane was prepared by UV-initiator induced graft polymerization of sulphate and phosphate bearing monomers (1:1 mol proportion) in pores of the host microporous poly(propylene) membrane.

Matrix supported tailored polymer for solid phase extraction of fluoride from variety of aqueous streams.

Fluoride related health hazards (fluorosis) are a major environmental problem in many regions of the world. It affects teeth; skeleton and its accumulation over a long period can lead to changes in the DNA structure. It is thus absolutely essential to bring down the fluoride levels to acceptable limits.

Silver nanoparticles embedded polymer sorbent for preconcentration of uranium from bio-aggressive aqueous media.

Adsorptive sorbent for bio-aggressive natural aqueous media like seawater was developed by one pot simultaneous synthesis of silver nanoparticles (Ag nps) and poly(ethylene glycol methacrylate phosphate) (PEGMP) by UV-initiator induced photo-polymerization. The photo-polymerization was carried out by irradiating N,N'-dimethylformamide (DMF) solution containing appropriate amounts of the functional monomer (ethylene glycol methacrylate phosphate), UV initiator (α,α'-dimethoxy-α-phenyl acetophenone), and Ag(+) ions with 365 nm UV light in a multilamps photoreactor. To increase mechanical strength, nano-composite sorbent (Ag@PEGMP) was also reinforced with thermally bonded non-woven poly(propylene) fibrous sheet.

Galvanic reactions involving silver nanoparticles embedded in cation-exchange membrane.

Galvanic reactions of Hg(2+), Rh(3+), and AuCl(4)(-) ions with Ag nanoparticles positioned near the surface and throughout the matrix of host poly(perfluorosulfonic) acid membrane have been studied.

Exchanges of uranium(VI) species in amidoxime-functionalized sorbents.

Amidoxime (AO)-functionalized polymer sorbents used in this study were prepared by two different routes involving UV grafting and electron-beam grafting of acrylonitrile (AN) into poly(propylene) fibrous and microporous sheets, and subsequent conversion of AN to AO groups by reacting the precursor sorbent with hydroxylamine. The values of self-diffusion coefficient (D(s)) of UO(2)(2+) in fibrous and sheet AO sorbents were found to be 1.1 x 10(-6) and 2.

Pore-functionalized polymer membranes for preconcentration of heavy metal ions.

Functionalized membranes containing carboxylate, phosphate and sulfonate groups were prepared by UV-initiator induced graft polymerization of the functional monomer (acrylic acid, ethylene glycol methacrylate phosphate (EGMP) and 2-acrylamido-2-methyl-1-propane sulfonic acid) with a crosslinker (methylenebisacrylamide) in the pores of poly(propylene) host membranes. The functionalized membranes thus obtained were characterized by gravimetry, FTIR spectroscopy, radiotracers and scanning electron microscopy for the degree of grafting and water uptake, presence of functional groups, ion-exchange capacity, and physical structure of the membranes, respectively. The uptakes of Cs(+), Ag(+), Sr(2+), Cd(2+), Hg(2+), Zn(2+), Eu(3+), Am(3+), Hf(4+) and Pu(4+) ions in the functionalized membranes were studied as a function of acidity of the equilibrating aqueous solution.