Europium Uptake Research Articles

Highly efficient uptake of Europium (III) and Americium (III) from acidic feeds using extraction chromatography resins containing N,N,N’,N’-tetra alkyl diglycolamides with varying alkyl chain length in an ionic liquid

A comparative study on the uptake of Eu(III) and Am(III) was carried out using four extraction chromatography (XC) resins impregnated with constant weight of the tetra-n-pentyl diglycolamide (TPDGA) ligands, viz. tetra-n-hexyl diglycolamide (THDGA), tetra-n-octyl diglycolamide (TODGA) and tetra-n-decyl diglycolamide (TDDGA) along with C4mim·NTf2, a room temperature ionic liquid (RTIL), from nitric acid feed solutions. The uptake of Eu(III) was higher than that of Am(III) while the uptake trend with the four XC resins followed the order: TPDGA > THDGA > TODGA > TDDGA, which was opposite to the alkyl chain length attached to the DGA extractant. When constant moles of the extractants were used, the observed trend was TODGA > THDGA > TDDGA > TPDGA. Also, for all the four XC resins, the uptake of both Eu(III) and Am(III) ions increased with increasing nitric acid concentration. The uptake data with all the four resins were fitted into different kinetic and isotherm models which conformed to a pseudo-second order kinetics and Langmuir monolayer sorption isotherm. Furthermore, columns were prepared with these XC resins and were used to obtain breakthrough profiles using a feed solution containing 0.55g/L Eu(III) in 3M HNO3. Subsequently, the elution of the loaded metal ion from the column was accomplished with a strippant solution containing 1M guanidine carbonate+0.05M EDTA in distilled water. Elution profiles for all the four resins showed sharp peaks with almost no tailing.

Synthesis of potential Ca–Mg–Al layered double hydroxides coated graphene oxide composites for simultaneous uptake of europium and fulvic acid from wastewater systems

High background electrolyte and natural organic matter are favorable to migration of hazardous radionuclides in geochemical repository. Herein, Ca–Mg–Al layered double hydroxide coated onto graphene oxide (Ca–Mg–Al LDH/GO) composites were successfully synthesized, characterized and adopted to decontaminate Eu(III) and fulvic acid (FA) under diverse experimental conditions. Diverse concentration gradients and different addition sequences on Eu(III) and FA were also obtained, which revealed different interaction mechanisms. The experimental results displayed that the coexistence of FA and Eu(III) respectively promoted adsorption performance of Eu(III) and FA under the ternary systems. The acquired Ca–Mg–Al LDH/GO composites were adopted to remove Eu(III) and FA, which further illustrated excellent chemo-physical stability and adsorption capacity of 1.12 × 10−3 mol/g and 3.54 × 10−4 mol/g, respectively. The remarkable adsorption performances of Ca–Mg–Al LDH/GO were confirmed through kinetic procedures and depending-temperature isotherms, illustrating that the kinetics processes were simulated using pseudo-second-order pattern, and the adsorption isotherms were splendidly simulated using Langmuir pattern. XPS spectrum analysis revealed that these containing oxygen groups took significant part in the restricting of Eu(III) and FA onto the surfaces of Ca–Mg–Al LDH/GO composites. In view of experimental results, the Ca–Mg–Al LDH/GO composites can be as potential adsorbents with availably recycled reusability for the decontamination of Eu(III) and FA from nuclear fuel partition or nuclear wastewater systems.

Magnetite nanoparticles with aminomethylenephosphonic groups: synthesis, characterization and uptake of europium(III) ions from aqueous media.

Two adsorbents with covalently bound aminomethylenephosphonic acid functions (and referred to as MNPs/AMPA and MNPs/SiO2-AMPA) were synthesized from two types of amino-functionalized magnetic nanoparticles (MNPs) via Moedritzer-Irani reaction. The sorbents with anchored dopamine ligand (MNPs/dopa) or aminopropyl groups (MNPs/SiO2-NH2), and the MNPs/AMPA were characterized by X-ray diffraction, FTIR, transmission electron microscopy and vibrating sample magnetometry. Surface modification does not adversely impact the physical properties of the starting magnetite. Compared to the size of the unmodified Fe3O4 (magnetite) nanoparticles (7-12nm), the average size of functionalized nanoparticles is increased to 10-16nm. Similarly, the magnetic saturation decreased from 67.5emu g-1 to 42.0emug-1, and the surface area is increased up to 205 m2g-1 for MNPs/SiO2-AMPA. The kinetics of the adsorption of Eu(III) on the sorbent is ultra-fast, and equilibria are attained within 5-10min at room temperature. The adsorption kinetics can be described by a pseudo-second-order model. Adsorption and desorption conditions were tested with respect to the removal of Eu(III) ions from water solution. The adsorption capacities for Eu(III) at pH7.0 are 77mgg-1 and 69mgg-1 for MNPs/AMPA and MNPs/SiO2-AMPA nanoparticles, respectively. Eu(III) was quantified by ICP-MS. The limit of detection (LOD) for Eu(III) is 0.05ngL-1 (based on the 3σ criterion), with an enrichment factor of 150. The selectivity over ions such as Tb(III), Fe(III), Zn(II), Cu(II), and Ca(II) ions was studied. Under optimal condition the distribution coefficient for Eu(III) relative to these ions is near 105mLg-1. The sorbents can be easily retrieved from even large volumes of aqueous solutions by magnetic separations. The method was tested for spiked water samples (with recoveries from 96.6-102.5%) and for rock minerals. Graphical abstract A schematic showing the regeneration of magnetite nanoparticles (MNPs), core-shell (MNPs/SiO2), and the structures with covalently bonded aminomethylenephosphonic acid (AMPA) after preconcentration of Eu(III) from largewater sample volumes onto a small specimen.

Sorption of Eu(III) on quartz at high salt concentrations

Sorption of Eu(III) onto quartz from highly saline solutions (up to 5 M NaCl) for pHc 2–9 ha s been studied by measuring sorption edges. The acid-base titrations of the silica surface suggest the rather unusual presence of two different sites that has been the object of recent discussions in the literature. Europium uptake results show the usual behaviour with a steep pH-edge and nearly complete removal at sufficiently high pH. Previous spectroscopic data on this system suggest the presence of two bidentate surface complexes with different proton stoichiometry. Based on this, a self-consistent Surface Complexation Model (SCM) was fitted to the full set of experimental data, from 0.1 to 5 M NaCl, using a coupled Pitzer/surface complexation approach. The Pitzer model was applied to aqueous species. A Basic Stern Model was used for interfacial electrostatics of the system, which includes ion-specific effects via ion-pair formation. Parameter fitting was done using the general parameter estimation software UCODE coupled to a modified version of FITEQL2 involving separate calculations of the respective ionic strength corrections. At high ionic strength (>1 M), the surface potential is strongly screened by ion-pair formation and the diffuse layer potential is negligibly low, which justifies the extension of the standard electrostatic model to these harsh conditions. Overall, our model is able to describe the full set of analysed data. To the knowledge of the authors this is the first comprehensive work studying solid surface titrations and cation uptake up to high salt levels and applying electrostatics models to describe the solid interface at these particular conditions. It is expected that these first systematic data acquisition along with the detailed modelling can serve as a benchmark for the modelling of future studies on sorption in highly saline systems.

Optimum conditions of pH, temperature and preculture for biosorption of europium by microalgae Acutodesmus acuminatus

In this study, we investigated characteristics of europium biosorption by Acutodesmus acuminatus, with particular aim to recover rare earth elements from electronical waste. The adsorption capacity of europium was compared under various time duration, pH, temperature and preculture conditions. The maximum adsorption capacity of 174.2 mg/g-dry was achieved under pH at 4.7 at 40 °C. This capacity was higher or comparable to other biosorbents in the past studies. Decrease of adsorption capacity at higher temperature indicated contribution of biological mechanisms rather than physico-chemical adsorption. Presence of intra-cellular europium particles observed by TEM-EDX and effect of preculture conditions suggested that intra-cellular uptake of europium resulted in high capacity of europium biosorption by A. acuminatus.

Effect of different complexing ligands on europium uptake from aqueous phase by kaolinite: batch sorption and fluorescence studies

The fluorescence studies suggested that the Eu(iii) sorbs as Eu(iii)–oxalate complex (binary system) onto kaolinite surface in the ternary system of Eu(iii), oxalic acid and kaolinite at circumneutral pH conditions.

The uptake of europium by reduced graphene oxide-supported nanoscale zerovalent iron investigated by batch and modeling techniques

The reduced graphene oxide-supported nanoscale zerovalent iron (NZVI@rGO) composites were synthesized towards the uptake of europium (Eu(III)) in environmental cleanup. In this study, the effect of environmental factors on the uptake of Eu(III) from aqueous solutions on NZVI@rGO composites was investigated under ambient conditions by batch techniques. The uptake kinetics indicated that the uptake of Eu(III) on NZVI@rGO composites can be satisfactorily fitted by pseudo-second order kinetic model. The uptake of Eu(III) on NZVI@rGO composites was independent of ionic strength at pH > 5.0, indicating that inner-sphere surface complexation dominated the uptake of Eu(III) on NZVI@rGO composites. It is demonstrated that the maximum uptake capacities of NZVI@rGO composites for Eu(III) calculated from Langmuir models was 96.675mg/g at pH 5.0 and T=293K. The thermodynamic parameters indicated that the uptake of Eu(III) on NZVI@rGO composites was an endothermic and spontaneous process. Based on surface complexation modeling, the diffuse layer model gave an excellent fits to the uptake of Eu(III) on NZVI@rGO composites with cation exchange complexes (X3Eu species) at pH<4.5, mononuclear and monodentate complexes (SOEu2+ species) at pH 5.0–7.0, and mononuclear and bidentate complexes ((SO)2Eu(OH)2− species) at pH>7.0, respectively. The results indicated that NZVI@rGO composites can be considered as a promising adsorbent for the uptake of trivalent radionuclides from wastewaters in environmental cleanup.

Efficiencies of chitosan nanoparticles and crab shell particles in europium uptake from aqueous solutions through biosorption: Synthesis and characterization

The US Department of Energy declared Europium as one of the most critical rare earth elements. Industrial and radioactive wastewater containing Europium(III) may pose a problem to the environment when discharged into the groundwater or aquatic streams. This work reports the uptake of Europium from aqueous solution by biosorption onto crab shells powder and chitosan nanoparticles as novel biosorbents for Europium(III) ion. Chitosan Nanoparticles were synthesized by the ionic gelation method. Equilibrium and kinetic studies were conducted by batch adsorption studies in order to find the optimum metal uptake conditions with the present biosorbents. The extent of adsorption was found to be a function of solution pH, contact time, metal ion concentration and adsorbent dose. The experimental data were fitted to Langmuir, Freundlich and Temkin isotherms and the data were analyzed on the basis of Lagergren pseudo-first order, pseudo-second order and Weber–Morris models. The maximum monolayer adsorption capacity of the Chitosan nanoparticles and crab shell powder was found to be 114 and 3.2 mg g−1 respectively. The results indicated the Chitosan nanoparticles could remove Europium(III) more effectively than the crab shell powder under optimum conditions. Characterization and ligand complexation behavior of the chitosan nanoparticles and crab shell powder were extensively interrogated by Dynamic Light Scattering (DLS), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy analysis (SEM).

Extraction chromatographic material with HDEHP on polyacrylonitrile (PAN)

Four composite materials with di-(2-ethylhexyl) phosphoric acid (HDEHP) as an extraction agent and PAN as a binding polymer were studied in this work. The intended use of these materials is in extraction chromatography. They were prepared by various methods and contained different amounts of HDEHP. The properties were compared by studying europium uptake from nitric acid solutions. Materials prepared by direct incorporation of extraction agent into PAN polymer during beads production and with up to 40% (w/w) of HDEHP are suitable for analytical separations. Materials with high capacity can be prepared by impregnation of ready-made PAN beads.

Study of europium and selected actinides uptake on composite material CMPO-PAN

Modified CMPO-PAN production was used and the resulting composite material was tested for purposes of extraction chromatography. A commercially available extraction agent octyl(phenyl)-N,N′-diisobutylcarbamoylmethylphosphine oxide (CMPO) and polyacrylonitrile (PAN) were used. The europium uptake kinetics by composite material was studied in two different nitric acid solutions. The dependences of weight distribution coefficients (Dg) of europium, americium, plutonium, uranium, and neptunium on nitric acid concentration (0.01–5 mol L−1) in the presence of sodium nitrate (0.1 mol L−1) were determined. High Dg-values were found in 0.1–5 M nitric acid for all elements tested. Increase in europium and americium Dg-values with decrease in nitric acid concentration (bellow 0.1 mol L−1) was observed. This behaviour in diluted nitric acid solutions differs from the behaviour of the similar materials with another support. CMPO-PAN composite material was compared with commercially available TRU Resin. Dg-values of the tested elements in all solutions used were higher for CMPO-PAN than for TRU Resin. The retention of the studied elements on CMPO-PAN in hydrochloric acid was made as a screening study.

Preparation and evaluation of cerium(IV) tungstate powder as inorganic exchanger in sorption of cobalt and europium ions from aqueous solutions

Cerium(IV) tungstate powder was chemically synthesized and exploited as adsorbent material for the decontamination study of cobalt and europium ions from radioactive waste solutions under simulated conditions using batch technique. The influences of pH, particle size and temperature have been reported. The uptake of europium was found to be slightly greater than that of cobalt and the apparent sorption capacity increases with increase in temperature. Thermodynamic parameters such as changes in Gibbs free energy (Δ G°), enthalpy (Δ H°), and entropy (Δ S°) were calculated. The numerical value of Δ G° decreases with an increase in temperature, indicating that the sorption reaction of each ion was spontaneous and more favorable at higher temperature. The positive values of Δ H° correspond to the endothermic nature of sorption processes and suggested that chemisorption was the predominant mechanism. A comparison of kinetic models applied to the sorption rate data of each ion was evaluated for the pseudo first-order, the pseudo second-order, intraparticle diffusion and homogeneous particle diffusion kinetic models. The results showed that both the pseudo second-order and the homogeneous particle diffusion models were found to best correlate the experimental rate data. The numerical values of the rate constants and particle diffusion coefficients were determined from the graphical representation of the proposed models. Activation energy ( E a) and entropy (Δ S ‡) of activation were also computed from the linearized form of Arrhenius equation.

Study of solid extractants based on malonamides, diglycolamides, and bipyridines for the partitioning of minor actinides from high active wastes

In this work, the performance of the solid extractants with polyacrylonitrile (PAN) binding matrix was studied for the separation of lanthanides and actinides from nitric acid solutions. As extractants, incorporated into the PAN matrix, the N,N′-dimethyl-N,N′-dibutyltetradecylmalonamide (DMDBTDMA), N,N′-dimethyl-N,N′-dioctyl-hexy-loxyethylmalonamide (DMDOHEMA), N,N,N′,N′-tetraoctyldiglycolamide (TODGA), 6,6′-bis-(5,6-dipentyl-[1,2,4]triazin-3-yl[2,2′]bipyridinyl (C5BTBP) were used. Weight distribution coefficients Dg of europium and several actinides have been determined for all the composite materials. The kinetics of europium uptake, practical dynamic extraction capacities, and extraction isotherms were also determined. The results obtained revealed that the solid extractants studied are prospective for the partitioning of lanthanides and actinides from liquid radioactive wastes.

Ion exchange studies of europium on uranium antimonate

Uranium antimonate (USb) has been prepared by the precipitation reaction between uranyl nitrate and potassium pyroantimonate and it has been characterized by X-ray diffraction (XRD), thermal analysis, energy disperse X-ray florescence, and pH titration. Ion exchange of europium on USb as a function of time, temperature, concentration of nitric acid and europium has been studied. The distribution coefficient of europium on USb was found to decrease from ∼10 5 ml g −1 at 0.05 M nitric acid to 22 ml g −1 at 2 M nitric acid. Uptake of europium was fitt to a particle diffusion equation and the diffusion coefficient ( D i) was calculated from the slope of Bt– t plots. The energy ( E a) and entropy (Δ S ∗) of activation for the sorption of europium were found to be 17 kJ mol −1 and −67.9 J mol −1 K −1, respectively. Sorption data obtained at various concentrations of europium were fitted into a Langmuir adsorption isotherm and the enthalpy change accompanied by the sorption of europium was determined by the temperature variation method.

Europium uptake and partitioning in oat (Avena sativa) roots as studied by laser-induced fluorescence spectroscopy and confocal microscopy profiling technique.

The uptake of Eu3+ by elongating oat roots was studied by fluorescence spectroscopy, fluorescence lifetime measurement, and a laser excitation time-resolved confocal fluorescence profiling technique. The results of this work indicated that initial uptake of Eu3+ was highest within the undifferentiated cells of the root tip just behind the root cap, a region of maximal cell growth and differentiation and with incomplete formation of the Casparian strip around the central vascular cylinder. Distribution of assimilated Eu3+ within the root's differentiation and elongation zone was nonuniform. Higher concentrations of Eu3+ were observed within the vascular cylinder, specifically in the phloem and developing xylem parenchyma. Elevated levels of the metal were also observed in the root hairs of the mature root zone. Fluorescence spectroscopic characteristics of the assimilated Eu3+ suggested that the Eu3+ exists as inner-sphere mononuclear complexes inside the root. This work also demonstrated the effectiveness of a time-resolved Eu3+ fluorescence spectroscopy and confocal fluorescence profiling techniques for the in vivo, real-time study of metal [Eu3+] accumulation by a functioning intact plant root. This approach can prove valuable for basic and applied studies in plant nutrition and environmental uptake of actinide radionuclides.

Study on uptake of europium by the thin film of apatite and smectite mixture using RBS and micro-PIXE

Uptake of Eu, one of the rare earth elements, by a thin film of apatite and smectite mixture has been studied. The thin film of approximately few tens of μm in thickness was contacted with Eu solution between 1.0×10 −5 and 1.0×10 −3 mol l −1 for 2 days at 25°C and at pH 4.5. After separating the thin film from the solution, depth and spatial distributions of Eu were determined by Rutherford backscattering spectroscopy (RBS) system and micro-proton-induced X-ray emission (μ-PIXE) analyzing system, respectively, in the TIARA facility of Japan Atomic Energy Research Institute. RBS spectrum shows that Eu is distributed from the surface to deeper position. This indicates that Eu is not only sorbed on the surface of the thin film, but also penetrates to deeper from the surface. The spatial distribution of Eu obtained by μ-PIXE does not correspond to Si but to P. This is the direct evidence that most of the sorbed Eu are associated with apatite in the thin film. Therefore, it is concluded that RBS and μ-PIXE analyses are effective to examine the sorption behavior of elements on the mixture.

Uptake of cesium, strontium and europium by a poly(sodium acrylate-acrylic acid) hydrogel

The uptake of cesium, strontium and europium from dilute nitric acid solutions by a poly(sodium acrylate-acrylic acid) PAA hydrogel has been investigated. pH variations are consistent with cation exchange processes: COO −, Na + H + , COO −, Na + M m+ ( M m+ = Cs + and Sr 2+) and COOH Eu 3+ . Saturation of the gel is achieved for metal/carboxylate ratios R = 0.5. The swelling ratios of gels loaded with metal cations are those of uncharged, shrunk gels (Sr, Eu) or of charged, swollen gels (Cs) in agreement with the formation of uncharged (COO) 2Sr, (COO) 2EuX (X = NO 3 or OH) type complexes and (COO −, Cs +) ion pairs. The metal cations are extracted in the gels following the order of their affinities with carboxylic groups Eu 3+ > Sr 2+ > Cs +. An increase of the ionic strength of the metal aqueous solution up to 0.5 M NaNO 3 leads to slightly decrease the europium uptake by the PAA hydrogel, but 0.1 M NaNO 3 is sufficient to prevent the Sr and Cs extractions.

Distribution and excretion of lanthanides: comparison between europium salts and complexes

Europium (152,154Eu) was intravenously injected into rats as: (i) the chloride salt at pH 7.4, (ii) the chloride salt at pH 3, (iii) the albumin complex and (iv) the DTPA complex, and tissue uptake was determined 24 h later. For the chlorides, the target organ for uptake was liver (about 60% of dose) whilst europium complexes were rapidly excreted in urine and were predominantly taken up into the kidney (about 0.5% of dose) and bone. Liver uptake of EuCl3, pH 7.4, corresponded to that of a colloidal material with most 152Eu present in the non-hepatocyte population; however, EuCl3, pH 3, was handled in a different manner, with significant uptake by hepatocytes. The differing tissue distributions of EuCl3 and Eu-albumin suggest that plasma albumin does not readily bind injected EuCl3. Renal uptake of europium, although a relatively low proportion of the injected dose, was associated with many subcellular fractions, including lysosomes, suggesting significant intracellular uptake and thus possible retention.

Europium uptake and accumulation in the cells of the crab, carcinus maenas

1. 1. 152Eu has been given to crabs, Carcinus maenas, in seawater or by gastric intubation to see how its metabolism correlates with that of 241Am which is accumulating in the environment from the decay of plutonium. 2. 2. Europium is mainly adsorbed onto skeletal structures but small amounts are absorbed from the stomach and accumulated in the digestive gland and muscle. Absorption appears to occur via the ionic form and is facilitated by the calcium ionophore Lasalocid. 3. 3. Studies were made on the intracellular distribution of 152Eu in the hepatopancreas. Most of the isotope is associated with the supernatant fraction although some occurred in granules. 4. 4. The role of ionic radius and charge is discussed in relation to the metabolism of europium and its effects on calcium and iron pathways. It is concluded that in many ways europium is a good analogue for the much more radiotoxic americium and that its use in risk assessment should be considered further.