Affinity For Uranium Research Articles

CO2-in-Water Pickering Emulsion-Assisted Polymerization-Induced Self-Assembly of Raspberry-like sorbent microbeads for uranium adsorption

• An amino oxime functionalized raspberry-like sorbent microbeads is firstly prepared for uranium extraction. • A new idea for the controllable interface assembly of nano-sized particles was provided. • RL-SMs exhibited a remarkable uranium removal efficiency when multiple metal ions coexist. • RL-SMs shows a fast adsorption equilibrium, which only need 30 min. Highly efficient adsorption of radioactive uranium from seawater is a grand challenge of mounting severity as the energy demand increases. To address this, a salicylaldoxime functionalized raspberry-like microbeads sorbent is created to achieve highly efficient uranium adsorption via the CO 2 -in-Water Pickering emulsion-assisted polymerization-induced self-assembly method. The prepared raspberry-like microbeads sorbent with a high density of accessible functional groups exhibits the maximum uranium adsorption capacity of 41.02 mg g −1 within 30 min, the time required to reach adsorption equilibrium is shorter than most of the reported amine-oxime functionalized microsphere adsorbents. In addition, under the coexistence of high-concentration metals such as Na + , Mg 2+ , K + , Ca 2+ , etc., the raspberry-like microbeads sorbent still showed the best affinity for uranium, which is mainly benefit from the specific binding between amine oxime group and uranium. Our work not only provides a general strategy for the rapid and selective adsorption of uranium from seawater, but also provides a new perspective for the controlled assembly of NSs and the preparation of nano-hybrid materials combining the advantages of micro/nano structures.

Bis(hydroxylamino)triazines: High Selectivity and Hydrolytic Stability of Hydroxylamine-Based Ligands for Uranyl Compared to Vanadium(V) and Iron(III).

The development of ligands with high selectivity and affinity for uranium is critical in the extraction of uranium from human body, radioactive waste, and seawater. A scientific challenge is the improvement of the selectivity of chelators for uranium over other heavy metals, including iron and vanadium. Flat ligands with hard donor atoms that satisfy the geometric and electronic requirements of the UVIO22+ exhibit high selectivity for the uranyl moiety. The bis(hydroxylamino)(triazine) ligand, 2,6-bis[hydroxy(methyl)amino]-4-morpholino-1,3,5-triazine (H2bihyat), a strong binder for hard metal ions (FeIII, TiIV, VV, and MoVI), reacted with [UVIO2(NO3)2(H2O)2]·4H2O in aqueous solution and resulted in the isolation of the complexes [UVIO2(bihyat)(H2O)], [UVIO2(bihyat)2]2-, and {[UVIO2(bihyat)(μ-OH)]}22-. These three species are in equilibrium in aqueous solution, and their abundance varies with the concentration of H2bihyat and the pH. Reaction of H2bihyat with [UVIO2(NO3)2(H2O)2]·4H2O in CH3CN gave the trinuclear complex [UVI3O6(bihyat)2(μ-bihyat)2]2-, which is the major species in organic solvents. The dynamics between the UVIO22+ and the free ligand H2bihyat in aqueous and dimethyl sulfoxide solutions; the metal binding ability of the H2bihyat over pyridine-2,6-dicarboxylic acid (H2dipic) or glutarimidedioxime for UVIO22+, and the selectivity of the H2bihyat to bind UVIO22+ in comparison to VVO43- and FeIII in either UVIO22+/VVO43- or UVIO22+/FeIII solutions were examined by NMR and UV-vis spectroscopies. The results revealed that H2bihyat is a superior ligand for UVIO22+ with high selectivity compared to FeIII and VVO43-, which increases at higher pHs. Thus, this type of ligand might find applications in the extraction of uranium from the sea and its removal from the environment and the human body.

Zeolitic Imidazolate Framework-67: A promising candidate for recovery of uranium (VI) from seawater

With the development of the nuclear industry and nuclear technology application, it is important to develop adsorbents with high selectivity and adsorption capacity for removal of uranium from nuclear waste and for trace uranium capture from seawater. In this report, we investigated for the first time Zeolitic Imidazolate Framework-67 (ZIF-67) for the removal of uranium from aqueous solutions and trace uranium from simulated seawater. The influence of pH, contact time and initial uranium concentration were studied. Results showed that ZIF-67 possessed an ultrahigh adsorption capacity (Qm = 1683.8 mg g−1) and high removal rate at both ppb and ppm levels (>99%) for uranium. The adsorption process fits well with the Langmuir isotherm model and pseudo-second-order rate equation. In addition to the general characterization of ZIF-67 by XRD, SEM, TEM, and FT-IR, the uranium-adsorbed ZIF-67 was investigated by X-ray photoelectron spectroscopy (XPS), which revealed a possible mechanism that involved the existence of large amounts of CoOH and active sites produced after the dispersion of ZIF-67 in water; CoOH was the key factor that ZIF-67 possessed to realise a high adsorption capacity and affinity for uranium (VI).

Enhancement of uranium(VI) biosorption by chemically modified marine-derived mangrove endophytic fungus Fusarium sp. #ZZF51

Fusarium sp. #ZZF51, mangrove endophytic fungus originated from South China Sea coast, was chemically modified by formaldehyde, methanol and acetic acid to enhance its affinity of uranium(VI) from waste water. The influencing factors about uranium(VI) adsorption such as contact time, solution pH, the ratio of solid/liquid (S/L) and initial uranium(VI) concentration were investigated, and the suitable adsorption isotherm and kinetic models were determined. In addition, the biosorption mechanism was also discussed by FTIR analysis. Experimental results show that the maximum biosorption capacity of formaldehyde-treated biomass for uranium(VI) at the optimized condition of pH 6.0, S/L 0.6 and equilibrium time 90 min is 318.04 mg g−1, and those of methanol-treated and HAc-treated biomass are 311.95 and 351.67 mg g−1 at the same pH and S/L values but different equilibrium time of 60 and 90 min, respectively. Thus the maximum biosorption capacity of the three kind of modified biomass have greatly surpassed that of the raw biomass (21.42 mg g−1). The study of kinetic exhibits a high level of compliance with the Lagergren’s pseudo-second-order kinetic models. Langumir and Freundlich models have proved to be well able to explain the sorption equilibrium with the satisfactory correlation coefficients higher than 0.96. FTIR analysis reveals that the carboxyl, amino and hydroxyl groups on the cell wall of Fusarium sp. #ZZF51 play an important role in uranium(VI) biosorption process.

Development of New Cationic Exchangers for the Recovery of Uranium (VI) from Concentrated Phosphoric Acid

The extraction of uranium (VI) from 5.3 mol.L−1 phosphoric acid with a series of phosphoric, phosphinic, dithiophosphoric, or dithiophosphinic acid derivatives (0.5 mol.L−1) in mixture with 0.125 mol.L−1 TOPO in Isane IP 185 has been investigated. In the frame of the present work, eight acidic phosphorus and thiophosphorus compounds have been synthesized: bis(1,3-diisobutoxypropan-2-yl) phosphoric acid, bis(1,3-bis-(butylthio)propan-2-yl) phosphoric acid, bis(5,8,12,15-tetraoxanonadecan-10-yl) phosphoric acid, bis(1-butoxyheptan-2-yl) phosphoric acid, bis(undecan-6-yl) phosphoric acid, bis(2-(1,3-dibutoxypropan-2-yloxy)ethyl) phosphoric acid, bis(3-butoxy-2-(butoxymethyl)-2-methylpropyl) phosphinic acid, bis(1,3-dibutoxypropan-2-yl) dithiophosphoric acid. The properties of these molecules in mixtures with TOPO have been compared with those of other extractants such as bis(2-ethylhexyl) phosphoric acid, bis(2-ethylhexyl) dithiophosphoric acid, bis(2-ethylhexyl) phosphinic acid, Cyanex® 272, and Cyanex® 301. The replacement of phosphoric acid-type extractant by their phosphinic homologues dramatically decreases the affinity for uranium (VI) whereas the replacement of the phosphoric and phosphinic acid-type extractants by their dithio homologues affects positively the distribution coefficient of uranium (VI). It also appears that the steric hindrance effect is responsible for a significant decrease of the distribution coefficient of uranium (VI). Supplemental materials are available for this article. Go to the publisher's online edition of Separation Science and Technology to view the free supplemental file.

Selective separation of radium and uranium from aqueous solutions by Chelex-100

The affinity of Chelex-100 for radium has been investigated as a function of pH and salinity compared to the Chelex-100 affinity for uranium to assess possible application of the resin for the selective separation of the two naturally occurring radionuclides from aqueous solutions. According to the experimental data the maximum chemical recovery of Chelex-100 is observed for uranium at pH 5 and for radium at pH 3 indicating a pH controlled selectivity of the resin for the two radionuclides. Moreover, the effect of salinity on the chemical recovery of radium is significant, resulting in a dramatic decrease of the former with increasing salinity. On the other hand, there is almost no effect of the salinity on the chemical recovery of uranium, indicating the higher affinity of Chelex-100 for uranium, which could be attributed to the formation of inner-sphere complexes of U(VI) with the iminoacetic moieties of the resin. The method has been successfully applied for the uranium separation from a radionuclide mixture.

The effect of physicochemical parameters on the separation recovery of plutonium and uranium from aqueous solutions by cation exchange

The effect of physicochemical parameters such as pH, salinity (e.g. [NaCl]) and competitive cation (e.g. Ca2+ and Fe3+) concentration on the separation recovery of plutonium and uranium from aqueous solutions by cation exchange has been investigated. The investigation was performed to evaluate the applicability of cation exchange as separation and pre-concentration method prior to the radiometric analysis of uranium and plutonium isotopes in natural water samples. Application of the method to test solutions of constant radionuclide concentration and variable composition (0.1, 0.5 and 1 M NaCl; 0.1 and 0.5 M Ca(NO3)2; 0.1 and 1 mM FeCl3; 10) has generally shown that: (1) the optimum pH is 4.5 for uranium and plutonium, (2) increasing salinity results in slightly lower for uranium and significantly higher chemical recovery plutonium and (3) the presence of Ca(II) cations doesn’t significantly affect the chemical recovery of both radionuclides. Contrary, the presence of Fe(III) cations ([Fe(III)] > 0.1 mM) results in significantly lower chemical recovery for both radionuclides (<50%). The later is attributed to the formation of Fe(III) colloids, which present increased chemical affinity for uranium and plutonium and hence compete with the radionuclide binding by the resin. Nevertheless, the results indicate that the method could be successfully applied to a wide range of natural waters.

Geophysical natural γ-ray well logging and spectrometric signatures of south AL-Abter phosphatic deposits in Syria

A combination of several exploration techniques was carried out in AL-Abter region, aiming at outlining the main characteristics of the phosphatic layers in this region. The techniques used in this research are natural γ-ray well logging, gamma and alpha-spectrometry. It is shown that uranium concentrations in the samples taken from the wells studied vary between 42.8 and 112.5 ppm with a standard deviation of 15.2 ppm. The P 2O 5 content varies between 20.5% and 28.31% with a standard deviation of 3.11% and the radioactive intensities vary between 150 and 275 counts per second (cps) with a standard deviation of 31 cps. The ratio of 234U/ 238U in the analyzed samples indicates that the study region is in radioactive equilibrium. The affinity of uranium and P 2O 5 to some trace elements, such as V, Sr, Cu and Ni has been verified through studying the correlation matrix of these elements.

Extraction of uranium from aqueous solution by coal and some other materials

Uranium in nature is commonly associated with carbonaceous material. Laboratory studies were therefore conducted to determine the relative ability of various types of carbonaceous material and some other substances to remove uranium from solution. The results of these experiments indicate that the low-rank coals are more effective in extracting uranium than any of the other materials used. A chemical determination shows that nearly 100 percent of the available uranium in solution is removed by subbituminous coal. The uranium is apparently retained in the coal by an irreversible process. The notable affinity of uranium for coalified plant remains suggests that some uranium deposits may have been formed over a long period of time by the extraction of uranium from dilute ground-water solutions. A possible application of the results of this work may be the extraction of uranium by coal from natural water or from waste solutions from uranium-processing industrial plants.