Selective Separation Of Uranium Research Articles

Phytate-modified MOFs grown on carbon nanotubes for efficient adsorption of uranium(Ⅵ) from seawater

The selective separation of uranium through adsorption remains a formidable challenge. Therefore, a one-step hydrothermal method was initially employed to anchor the metal-organic framework onto carbon nanotube oxides (NH2-MIL-101@MWCNT, the BET surface area of 1017.63 m2·g−1). Subsequently, a surface-functionalized composite nanoparticle (named PA-MIL-101@MWCNT, the BET surface area of up to 368.14 m2·g−1) was synthesized through phosphorylation via the Mannich reaction for uranium adsorption. Batch adsorption experiments unequivocally demonstrated that the modification with phytic acid led to a significant improvement in the uranium adsorption capacity of the composite material, achieving a maximum adsorption capacity of 599.77 mg·g−1. The initial adsorption rate of PA-MIL-101@MWCNT was exceptionally rapid, achieving 73.84 % of the maximum adsorption capacity within 10 min. Adsorption kinetics and thermodynamics indicated that uranium adsorption follows a single-molecule chemisorption mechanism. PA-MIL-101@MWCNT exhibits exceptional resistance to ionic interference within natural seawater, demonstrating excellent stability and recyclability. XPS and DFT calculations strongly supported the notion that the uranium adsorption mechanism was associated with the oxygen atoms in the PO and P-O functional groups. These findings suggest that PA-MIL-101@MWCNT can be considered an excellent material for uranium extraction from seawater, which is significant to the sustainable utilization of nuclear energy materials.

Shielding process for the effect of anions on uranium selective recovery and heavy metal removal from simulated mine effluents

The selective separation of uranium from uranium tailing wastewater is of great importance for environmental protection and nuclear energy development. The complexation of Cl−, SO42−, NO3–, and PO43− with UO22+ seriously hindered the achievement of this goal. Herein, a process for achieving it with the coexistence of anions and cations by shielding the influence of anions was designed. Thermodynamic calculations indicated that CO32– could enhance the retention of uranium in the solution by complexing with UO22+ and capturing UO22+ in UO2SO4 and UO2HPO4 to form water-soluble uranyl-carbonate. The capturing ability of CO32– was not diminished by the increase in anion concentration. And the electrochemical experiments revealed the high efficiency of uranium electrochemical extraction in the above system. In addition, the results showed that uranium could be separated from Co2+, Cd2+, and Ni2+ ions under the coexistence of Cl−, SO42−, NO3–, and PO43−, thus achieving the selective separation of uranium in the wastewater. And the retention ratio of impurity cations in the liquid phase after separation was less than 0.003. Overall, this method provides new insights into the selective separation of uranium and heavy metal removal in real uranium tailings wastewater.

Selective separation of uranium, zirconium and iodine from various fission products by 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and phosphoramide-functionalized ionic liquid

Selective separation of uranium, zirconium and iodine from various fission products by 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and phosphoramide-functionalized ionic liquid

Selective separation of uranium using modified Dowex 1X8 /TOA from carbonate leaching of Dolostone ore, Allouga area, Sinai

AbstractLeaching of uranium from a technological sample (680 mg/Kg U) in SW Sinai of Um Bogma Formation is carried out using a mix of sodium carbonte/sodium bicarbonate in presence of an oxidant (MnO2 or H2O2). The relevant factors e.g. (grain size=−200 mesh, alkali concentration= 100 g/l (3 : 1) mixed Na2CO3/NaHCO3, time=2 h, solid/liquid ratio=1/3, T=50 °C and H2O2=60 ml) of alkaline leaching of uranium have been optimized. This is followed by uranium recovery using an anion exchange resin, modified Dowex 1X8/TOA. Therefore, highly 92 % pure product of uranium has been obtained as sodium di‐urinate Na2U2O7.

Graphene Oxide Membranes for Tunable Ion Sieving in Acidic Radioactive Waste.

Graphene oxide (GO) membranes with unique nanolayer structure have demonstrated excellent separation capability based on their size‐selective effect, but there are few reports on achieving ion–ion separation, because it is difficult to inhibit the swelling effect of GO nano sheets as well as to precisely control the interlayer spacing d to a specific value between the sizes of different metal ions. Here, selective separation of uranium from acidic radioactive waste containing multication is achieved through a precise dual‐adjustment strategy on d. It is found that GO swelling is greatly restricted in highly acidic solution due to protonation effect. Then the interlayer spacing is further precisely reduced to below the diameter of uranyl ion by increasing the oxidation degree of GO. Sieving uranyl ions from other nuclide ions is successfully realized in pH =3–3 mol L−1 nitric acid solutions.

Geological and radioactivity studies accompanied by uranium recovery: Um Bogma Formation, southwestern Sinai, Egypt

High radioactive anomalies were recorded in the variegated claystones at the middle member of Um Bogma Formation, the eU-content reaches 1030 ppm, while eU/eTh ratio was equivalent to 11.7 times of Clark value. Associated elements with economic values as rare earth elements, vanadium and molybdenum were detected. Beside this, work focusing on uranium recovery from collected samples was investigated using different reagents and leaching techniques. Pug-leaching process using sulfuric acid at 100 °C is the most efficient leaching condition. Selective separation of uranium with high grade (38%) was obtained using synthetic quaternary ammonium sorbent grafted on silica particles.

Selective separation of uranium from sulfuric acid media using a polymer inclusion membrane containing alamine336

This study reports the extraction of U(VI) using poly(vinyl chloride)-based polymer inclusion membrane (PIM), possessing the extractant alamine336 and the plasticizer Polyoxyethylene alkyl ether (POE). The effects of transport parameters such as alamine336 and POE concentration in the PIM composition, uranium and sulfuric acid concentration in the feed phase, and the receiving phase type and concentration were discussed. Under the optimum conditions, 91.02 ± 2% of uranium was transported through the PIM. The prepared PIM showed excellent selectivity for U(VI) from the sulfuric acid leach solution. The stability of the PIM was found to be acceptable for 5 days.

Recovery of uranium and other valuable metals from substrates and waste from copper and phosphate industries

ABSTRACT Recovery of heavy metals and other useful materials from industrial waste is crucial because it reduces the environmental impact of the production facilities. The selective separation of uranium from such waste might be very important in the context of future energy production and the still essential role of nuclear power in the energy mix. The copper ores, waste from the copper industry, phosphate rocks and phosphogypsum were considered as sources of uranium in these studies. Apart from uranium, these materials also contain other valuable metals, e.g. rare earth elements. In the present work the procedures of extraction of uranium and accompanying metals designed for specific materials – the potential sources of metals, were reported.

Highly efficient extraction and selective separation of uranium (VI) from transition metals using new class of undiluted ionic liquids based on H-phosphonate anions

In this paper, we report the development of an environmental friendly process to decontaminate uranium-containing ores and nuclear wastes by using non-fluorinated ionic liquids (ILs). The main advantages of this extraction process are the absence of any organic diluent and extra extraction agents added to the organic phase. Moreover, the process is cost-effective and maybe applied as a sustainable hydrometallurgical method to recover uranium. The distribution ratio (DU) and the extraction efficiency (%E) of uranium(VI) (UO22+) were found to be dependent on the acidity of the aqueous phase, the extraction time, the alkyl chain length in the ILs, the concentration of the aqueous feed and molar quantity of ILs. The DU value is higher than 600 and the %E is equal to 98.6% when [HNO3]=7M. The extraction reactions follows a neutral partition or ionic exchange mechanism depending on nitric acid concentration. The nature of bonding in the extracted complexes was investigated by spectroscopic techniques. The potential use of Mor1-8-OP for the separation of UO22+ from a mixture containing transition metal ions Mn+ was also examined. The UO22+ ions were separated and extracted efficiently. These ILs are promising candidates for the recovery and separation of uranium.

Uranium analysis in drinking waters in Cyprus

Uranium determination and speciation in drinking waters consumed in Cyprus has been carried out by means of alpha-spectroscopy and thermodynamic calculations. Sampling included tap waters from different areas as well as local and imported bottled waters. The alpha-spectroscopic analysis was performed after selective separation of uranium by Chelex-100 and the uranium concentration in all waters was found below the WHO guideline. Based on the experimental data the annual radiation exposure of Cypriot population resulting from water consumption has been assessed. Thermodynamic calculations have shown that the ternary CaUO2(CO3) 3 2− and Ca2UO2(CO3)3(aq) complexes are the predominant species in drinking waters.

Selective separation of uranium from nuclear waste solution by bis(2,4,4-trimethylpentyl)phosphinic acid in ionic liquid and molecular diluents: a comparative study

Selective separation of uranium using bis(2,4,4-trimethylpentyl)phosphinic acid in xylene and C8mimNTf2 was investigated. For ionic liquid based system, the extraction kinetics was found to be slower with the predominance of ion exchange mechanism through [UO2(NO3)·2L]+, while for xylene based system solvation mechanism. The nature of the extracted species was found to be different in both the media as observed in luminescence study. Ionic liquid based system was more radioresistant than that of molecular diluents. Na2CO3 was successfully used for stripping. The selectivity was investigated by processing simulated high level waste of pressurized heavy water reactor origin.

Three novel triazine-based materials with different O/S/N set of donor atoms: One-step preparation and comparison of their capability in selective separation of uranium

Cyanuric chloride was chosen as a core skeleton which reacted with desired linker molecules, urea, thiourea and thiosemicarbazide, to prepare three novel functional covalent triazine-based frameworks, CCU (O-donor set), CCTU (S-donor set) and CCTS (S, N-donor set) respectively, designed for selective adsorption of U(VI). The products have high nitrogen concentration (>30wt%), regular structure, relatively high chemical and thermal stability. Adsorption behaviors of the products on U(VI) were examined by batch experiments. CCU and CCTU can extract U(VI) from simulated nuclear industrial effluent containing 12 co-existing cations with relatively high selectivity (54.4% and 54.2%, respectively). Especially, effects of donor atoms O/S on adsorption were investigated, and the outcomes indicate that the difference in coordinating ability between the donor atoms is weakened in large conjugated systems, and the related functional groups with originally very strong coordination abilities may not be the best choice for the application in selective adsorption of uranium and also other metals. The as-proposed approach can easily be expanded into design and preparation of new highly efficient adsorbents for selective separation and recovery of uranium through adjusting the structures, types and amounts of functional groups of adsorbents by choosing suitable linkers.

Synthesis of surface ion-imprinted magnetic microspheres by locating polymerization for rapid and selective separation of uranium(vi)

New surface ion-imprinted magnetic microspheres are developed by locating polymerization for uranium(vi) adsorption with ultrafast kinetics and high selectivity.

Selective separation of uranium(VI) from aqueous solutions using amine functionalized cellulose

Amine-modified grafted cellulose was obtained and its adsorption behaviour using batch technique towards U(VI) in aqueous solutions was studied. Maximum uptake capacity obtained at 25 °C was 150 mg/g. Selective separation of U(VI) from a mixture containing V(V) was achieved. Calculated thermodynamic parameters indicated exothermic nature of the adsorption process, while calculated kinetic parameters indicated that the interaction followed pseudo-second order kinetic model with relatively fast kinetics. Regeneration was achieved using 0.1 M H2SO4 with regeneration efficiency up to 95 % over three cycles.

Analysis of twenty five impurities in uranium matrix by ICP-MS with iron measurement optimized by using reaction collision cell, cold plasma or medium resolution

An analytical procedure was developed to determine the concentration of 25 impurities (Li, Be, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, Ag, Cd, In, Sm, Eu, Gd, Dy, W, Pb, Bi and Th) in a uranium matrix using the quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS). The dissolution of U3O8 powder was made with a mixture of hydrochloric acid and nitric acid. Then, a selective separation of uranium using the UTEVA column was used before measurement by Q-ICP-MS. The procedure developed was verified using the Certified Reference Material “Morille”. The analytical results agree well except for 5 elements where values are underestimated (Li, Be, In, Pb and Bi). Among the list of impurities, iron was particularly investigated because it is well known that this element possesses a polyatomic interference that increases the detection limit. A comparison between iron detection limits obtained with different methods was performed. Iron polyatomic interference was at least reduced, or at best entirely resolved in some cases, by using the cold plasma or the collision/reaction cell with several gases (He, NH3 and CH4). High-resolution ICP-MS was used to compare the results obtained. A detection limit as low as 8ngL−1 was achieved.

Selective Separation of Uranium(VI), Thorium(IV), and Lanthanum(III) from Their Aqueous Solutions using a Chelating Resin Containing Amine Functionality

A glycidyl methacrylate/divinylbenzene resin containing triethylenetetramine functional group was synthesized. The adsorption behavior of the obtained resin toward U(VI), Th(IV), and La(III) in aqueous solutions was investigated by batch and column techniques at different experimental conditions. Kinetic and thermodynamic characteristics of the adsorption process have been investigated. The regeneration of the loaded resin was also studied.

Chromatographic separation of uranium(VI) from other elements using L-valine and poly[dibenzo-18-crown-6

A selective and effective column chromatographic separation method has been developed for uranium(VI) using poly[dibenzo-18-crown-6]. The separation was carried out in L-valine medium. The adsorption of uranium(VI) was quantitative from 1.0 × 10−4 to 1 × 10−1 M of L-valine. Amongst various eluents 2.0–8.0 M hydrochloric acid, 1.0–4.0 M sulfuric acid, 1.0–5.0 M perchloric acid, 6.0–8.0 M hydrobromic acid and 5.0–6.0 M acetic acid were found to be efficient eluents for uranium(Vl). The capacity of poly[dibenzo-18-crown-6] for uranium(VI) was 0.25 ± 0.01 mmol/g of crown polymer. Uranium(VI) was separated from number of cations and anions in binary mixtures in which most of the cations and anions show a very high tolerance limit. The selective separation of uranium(VI) was carried out from multicomponent mixtures. The method was extended to determination of uranium(VI) in geological samples. The method is simple, rapid and selective with good reproducibility (approximately ∼2%).

Selective ion exchange separation of uranium from concomitant impurities in uranium materials and subsequent determination of the impurities by ICP-OES

An ion exchange method has been developed for the separation of uranium from trace level metallic impurities prior to their determination by inductively coupled plasma optical emission spectrometry (ICP-OES) in uranium materials. Selective separation of uranium from trace level metallic impurities consisting Cr, Co, Cu, Fe, Mn, Cd, Gd, Dy, Ni, and Ca was achieved on anion exchange resin Dowex 1 × 8 in sulphate medium. The resin (100–200 mesh, in chloride form) was packed in a small Teflon column (7.8 cm × 0.8 cm I.D.) and brought into sulphate form by passing 0.2 N ammonium sulphate solution. Optimum experimental conditions including pH and concentration of sulphate in the liquid phase were investigated for the effective uptake of uranium by the column. Uranium was selectively retained on the column as anionic complex with sulphate, while impurities were passed through the column. Post column solution was collected and analyzed by ICP-OES for the determination of metallic impurities. Up to 2,500 μg/mL of uranium was retained with >99% efficiency after passing 25 mL sample through the column at pH 3. Percentage recoveries obtained for most of the metallic impurities were >95% with relative standard deviations <5%. The method established was applied for the determination of gadolinium in urania–gadolinia (UO2–Gd2O3) ceramic nuclear fuel and excellent results were achieved. Solvent extraction method using tributylphosphate (TBP) as extractant was also applied for the separation of uranium in urania–gadolinia nuclear fuel samples prior to the determination of gadolinium by ICP-OES. The results obtained with the present method were found very comparable with those of the solvent extraction method.

Extractive separation of uranium(VI) as perchlorate/chloroacetate complexes with 1-phenyl-2,3 dimethyl-5-pyrazolone and its applications

The extraction of U(VI) with 1-phenyl 2,3 dimethyl-5-pyrazolone, at a pH of 2.5, in the presence of common anions, like perchlorate and tri-, di-, and monochloroacetates has been investigated. The optimum experimental conditions have been evaluated by studying various parameters such as pH, equilibration period, reagent concentration, metal concentration, and solvents. Effect of diverse anions and cations on the extraction has also been studied. The extracted species, determined by log D - log R plots are represented as, [UO2(Apy)4(ClO4)2], [UO2(Apy)2(TCA)2], [UO2(Apy)2(DCA)2], [UO2(Apy)(H2O)(MCA)2]. The conditional stability constants of the quantitatively extracted complexes are calculated. The proposed method allows the selective separation of uranium(VI) from multicomponent mixtures and geological matrices and is also applied for the separation and chemical characterization of impurities at trace and ultratrace levels.

Solvent extraction and spectrophotometric determination of uranium(VI) with pyridine-2-carboxaldehyde 2-hydroxybenzoylhydrazone

Pyridine-2-carboxaldehyde 2-hydroxybenzoylhydrazone (PAHB) is proposed as an extractant for the separation and spectrophotometric determination of uranium(VI). The optimum extraction conditions have been evaluated by studying various parameters such as pH, diluents, equilibration time and reagent concentration. PAHB forms yellow colored complex with uranium(VI) in the pH range of 3.5-4.6 which can be extracted by isobutyl methyl ketone. The extracted complex exhibits an absorption maximum at 375 nm. Beer's law was obeyed in the concentration range 1.0-5.6 ppm of uranium(VI). The nature of the extracted species (1:2) was determined by log D-log c plot. The proposed method permits selective separation of uranium(VI) from its binary mixtures. The method is also applied for the estimation of uranium in multicomponent mixtures and monazite sand.