Recovery Of Eu Research Articles

Recovery of europium from E-waste using redox active tetrathiotungstate ligands

Rare-earth elements (REEs) are critical to our modern economy, yet their mining from natural ores bears a profound environmental impact. Traditional separation techniques are chemical and energy-intensive because their chemical similarities make REEs very challenging to purify, requiring multiple extraction steps to achieve high purity products. This emphasizes the need for sustainable and straightforward separation methods. Here we introduce a strategy for the direct separation of europium (Eu) from complex mixtures under ambient conditions, leveraging on the redox non innocence of purely inorganic tungsten tetrathiolate (WS42−) ligands. The recovery of Eu is achieved upon reduction of Eu(III) to a Eu(II) coordination polymer, driven by an induced internal electron transfer from the tetrathiotungstate ligand. Applying this strategy to unconventional feedstock such as spent energy-saving lamps allows selective europium recovery with separation factors over 1000 and recovery efficiency as high as 99% without pre-treatment of the waste.

Extraction of rare earth Eu from waste blue phosphor strengthened by microwave alkali roasting

Spent phosphor is an important secondary resource for extracting rare earth elements. Microwave absorption properties and enhanced extraction of Eu from blue phosphor by microwave alkali roasting were studied. Dielectric properties of alkali roasting system were measured by resonator perturbation method. Dielectric constant increases linearly from 250 °C until it reaches a peak at 400 °C. The dielectric loss reaches a higher value at 400–550 °C, due to the strong microwave absorption properties of molten alkali and roasted products. Effects of roasting temperature, roasting time and alkali addition amount on Eu leaching were investigated. The phosphor was completely decomposed into Eu2O3, BaCO3 and MgO at 400 °C. The alkaline decomposition process of phosphor is more consistent with diffusion control model with Eα being 28.9 kJ/mol. Effects of the main leaching conditions on Eu leaching were investigated. The leaching kinetic of Eu was in line with diffusion control model with Eα being 5.74 kJ/mol. The leaching rules of rare earths in the mixed phosphor were studied. The results showed that the presence of red and green phosphor affected the recovery of blue phosphor. The optimum process parameters of rare earth recovery in single blue phosphor and mixed phosphor were obtained, and the recovery of Eu were 97.81% and 94.80%, respectively. Microwave alkali roasting promoted the dissociation of phosphor and leaching of rare earths. The results can provide reference for the efficient and selective recovery of rare earths in phosphors.

Recovery and concentration of Eu(III) from phosphogypsum leachate using ouricuri endocarp

Ouricuri endocarp was utilized as a biosorbent for the recovery of europium (Eu(III)) from aqueous solutions and rare earth elements (REEs) from authentic leachate derived from phosphogypsum, which encompasses various REEs. Various characterization techniques were applied to analyze the physicochemical and adsorptive properties of the biosorbent. The results indicate that the adsorption kinetic data conform well to the pseudo-first-order model, while the Liu model describes the equilibrium data well. Ouricuri endocarp and Eu interactions are favorable and spontaneous. The maximum adsorption capacity for Eu(III) is determined to be 22.9 mg/g according to the Liu model. Based on experimental results and adsorbent characteristics, the proposed adsorption mechanisms between ouricuri endocarp and Eu include ion exchange and electrostatic interactions as the primary mechanisms. The Eu(III) recovery is also feasible as a continuous flow process demonstrating inclined breakthrough curves and lower values of the length of the mass transfer zone. Ouricuri endocarp demonstrates its selectivity for recovering various REEs from authentic phosphogypsum leachate. It achieves a 98% recovery rate for Eu and approximately 60% for Ce, La, and Nd, affirming its efficacy under real-world conditions. Finally, concentration of REE was done by ashing loaded ouricuri endocarp, and a solid with around 34% (in weight) of REE is obtained.

Enhancing the adsorptive recovery of europium from real-world solid samples through the synergistic impact of lysozyme fibril and melamine phytate

Rare earth elements and precious metals have key multiple applications in varying fields inclusive of electronics, renewable energy and healthcare. Europium is often recovered in the recycling process as an essential metal having utility in several electronic items. Here, we report the preparation of a bio-sorbent, a self-assembly technique of lysozyme fibrils on phytate melamine (named LF-MP) for the recovery of Eu(III) from compact fluorescent lamps (CFL) waste. Spectroscopy-related techniques and electron microscopy not only confirms their interaction between the LF-MP and Eu(III) but also provided new insight into the morphology behavior, structure and chemical composition. The maximum Eu(III) adsorption was shown at a pH = 6.0, with an adsorption (Langmuir) capacity of 540 mg g−1. We further elucidated the mechanism of interaction between Eu(III) and LF-MP, mainly through electrostatic attraction followed by the formation of coordination bonding. It has been demonstrated that the LF-MP can recover Eu(III) from a wide range of europium-containing waste materials.

Scrutiny of variation of process parameters in the extraction of Eu(III) using [THAH]+[DEHP

Europium is classified as a crucial element by the energy department,USA.Its major applications includes use in phosphors and optical fiber owing to the optical as well as luminescent properties it shows.Europium is found in monazite, bastnaesite and xenotime minerals alongwith other lanthanides.Ionic liquids are known to extract neutral and charged species of metal from the feed which mostly depend on the type of metal ion, nature of the complex formed and composition of the aqueous feed. Bifunctional ionic liquid [THAH]+[DEHP]- in kerosene was employed to extract Eu(III) from aqueous nitrate solution in the presence of NaNO3 by solvent extraction.The process parameters like shaking time variation,salt molarity variation,aqueous phase pH variation, influence of diluent and temperature were examined to find conditions for extremum extraction of Eu(III).With increasing the shaking time between both the phases, the extraction percentage gets improved.Temperature displays unfavorable effect on the distribution ratio.Stripping studies show quantitative results for the recovery of Eu(III) from the loaded organic extract.

Potential application of graphene oxide and Aspergillus niger spores with high adsorption capacity for recovery of europium from red phosphor, compact fluorescent lamp and simulated radioactive waste

The recovery of rare earth elements (REEs) is a global challenge and the mining of rare earths has serious environmental implications due to the toxic waste released post mining. Hence, the rising demand for rare earths and their far reaching electronic applications necessitates an effective strategy to recover the REEs from more viable sources. In this work, the graphene oxide–Aspergillus niger spores (GO–A. niger spores) blend was utilized for adsorptive recovery of a precious rare earth Eu(III) and the adsorption variables like pH of the medium, adsorbent dosage, sorption kinetics, thermodynamics, and isotherm were optimized for the developed biosorbent. The adsorption process suits the Langmuir isotherm model with a maximum adsorption capacity of 147.3 mg/g. The pseudo–second–order kinetics is a perfect fit to describe the adsorption process. The results obtained through the Van't Hoff plot show negative free energy change (ΔG0) which implies the spontaneity of the adsorption process. The negative standard enthalpy change (ΔH0) values show that the nature of the adsorption process is exothermic. The analytical characterizations including Fourier transform infrared spectroscopy (FTIR), Raman, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), thermal gravimetric analysis (TGA), and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) were employed to study the biosorbent. The features of GO–A. niger spores biosorbent were applied to recover Eu(III) from real samples such as fluorescent lamp phosphor, red phosphor powder, and a simulated radioactive waste solution.

Can the recycling of europium from contaminated waters be achieved through living macroalgae? Study on accumulation and toxicological impacts under realistic concentrations

Europium (Eu) strategic importance for the manufacturing industry, high economic value and high supply risk, categorizes it as critical raw material. Due to anthropogenic contamination, Eu levels in ecosystems have been growing, which opens opportunities for innovation: its recovery and recycling from contaminated water as element source – circular economy. In this pioneering study, six widely available living marine macroalgae (Ulva intestinalis, Ulva lactuca, Gracilaria sp., Osmundea pinnatifida, Fucus vesiculosus and Fucus spiralis) were characterized (water content and specific surface area) and evaluated in the pre-concentration and recovery of Eu from contaminated seawater, under different relevant contamination scenarios (10, 152 and 500 μg L−1). U. lactuca and Gracilaria sp. (3 g L−1, fresh weight) proved to be the most effective in removing Eu, reaching up to 85% in 72 h, while the highest Eu enrichment was observed in U. intestinalis biomass, up to 827 μg g−1 (bioconcentration factor of 1800), which is higher than Eu levels in common apatite ores. The effect of Eu exposure on macroalgae growth rate and organism biochemical performance (LPO, SOD, GPx and GSTs) was also evaluated for the first time, to the best of our knowledge. Although no cellular damage was recorded, findings revealed toxicity and defence mechanisms activation, emphasizing the need of further studies on the potential risks associated with the presence of this emerging contaminant in aquatic ecosystems.

Lanthanide recovery by silica-Cyanex 272 material immobilized in alginate matrix.

Mesoporous silica impregnate with Cyanex 272 (bis/2,4,4-trimethylpentyl/phosphinic acid) extractant was immobilized into an alginate matrix to obtain a composite sorbent easy to use and applicable in fixed-bed column continuous systems. The sorption efficiency of this material was tested for the recovery of Eu(III) ions from aqueous solutions in batch and continuous mode. The competition among rare earths ions (europium, lanthanum, and lutetium) and among rare earths and calcium or sodium ions was investigated. High calcium concentrations strongly reduce the sorption capacity of the alginate matrix that composes the hybrid material and the Cyanex 272 impregnated into silica powder improves the rare earths' sorption performance in this calcium charged media. The experimental breakthrough curves obtained were satisfactory fitted by Thomas model.

Recovery of Eu from waste blue phosphors (BaMgAl10O17: Eu2+) by a sodium peroxide system: Kinetics and mechanism aspects

An efficient process for recycling Eu from BaMgAl11O19: Eu3+ (BAM) waste phosphors has been developed. The treatment of BAM by the sodium peroxide (Na2O2) calcining process followed by acid leaching was investigated. The results demonstrated that the calcination temperature and time more significantly influence the recovery efficiencies of metals than does the mass ratio of Na2O2 to BAM. More than 99% of Eu was recovered under the optimal conditions of 425 °C, mass ratio 1:1 and 30 min duration. The decomposition kinetics of BAM were studied using a series of typical solid-solid reaction kinetic models. The apparent activation energies Ea for the decomposition reactions of Eu, Ba, Al and Mg were calculated as 52.3 kJ/mol, 64.6 kJ/mol, 87.1 kJ/mol and 88.9 kJ/mol, respectively. XRD analysis indicated that the decomposition of BAM involved a multistep reaction. The reaction mechanism was also analyzed at the crystal structure level, which indicated that Ba and Eu atoms in the mirror plane of the unit cell of BAM were replaced by Na from Na2O2 at the beginning, and that BaO2 and Na2MgAl10O17 were produced. Then, Na2MgAl10O17 was decomposed to NaAl7O11 and MgAl2O4, and finally, NaAlO2, MgO, BaCO3 and Eu2O3 were generated at a higher temperature (600 °C). SEM and EDS analysis also demonstrated the proposed substitution and decomposition reactions. This work is expected to open new avenues and provides a theoretical basis for the highly efficient recovery of Eu from waste rare earth phosphors.

Selective Recovery of Europium and Yttrium Ions with Cyanex 272-Polyacrylonitrile Nanofibers.

Rare earth elements (REEs), which include lanthanides as yttrium and europium became crucial in the last decade in many sectors like automotive, energy, and defense. They contribute to the increment efficiency and performance of different products. In this paper nanofiber membranes have been successfully applied for the selective recovery of Eu(III) and Y(III) from aqueous solutions. Polyacrylonitrile (PAN) electrospun nanofibers were impregnated with a commercial organic extractant, Cyanex 272, in order to increase their affinity to rare earth metals ions. The coated nanofibers were characterized by SEM, ATR-FTIR, and TGA. Firstly, the adsorption of Eu(III) and Y(III) were evaluated in batch mode. Experimental data showed that the adsorption of Y(III) and Eu(III) corresponds to pseudo-second order model, with Langmuir sorption model being the best fit for both target ions. The results demonstrated that the adsorption capacity was high, showing a maximum capacity of 200 and 400 mg/g for Y(III) and Eu(III), respectively. Additionally, the presence of interfering ions does not show significative effects in the adsorption process. Finally, experiments in continuous mode indicated that the adsorption of the target elements is close to 100%, showing that PAN-272 is a promising material for the recovery of earth metal ions.

Eu (III) 'un Narcissus Tazetta L. Yaprak Tozu Üzerine Biyosorpsiyonu

In the present study, biosorption behaviours of novel biosorbent, Narcissus Tazetta L. leaf powder, were investigated for the separation of Eu(III) from aqueous solution. Batch experiments were conducted to examine the effect of various parameters such as contact time, initial pH, initial Eu(III) concentration, biosorbent dosage and temperature on the Eu(III) uptake. The biosorption process is fast, and equilibrium was established in 30 min. of contact time. It was found that the material has a significant biosorption capacity for europium in the pH range of 4-7. The results showed that the biosorption data fit Langmuir monolayer isotherm and pseudo-second order kinetic model well. Biosorption capacity of leaf powder was obtained as 122.0 mg g -1 at pH 7. Thermodynamic analysis indicates that the biosorption was spontaneous and endothermic in nature. Desorption efficiency(%) of 97.17 was achieved in single step using 0.1 mol L -1 HNO 3 solution. Surface area of the biosorbent and the average pore size were determined as 1.725 mg g -1 and 1.75 nm, respectively. The critical functional groups -CH, C-O, O-H, C=O and COO- which may have taken part for the biosorption were identified by infrared spectra data. It was deduced that N. Tazetta leaf powder can be used as an effective, costless, and eco-friendly biosorbent for the separation and recovery of Eu(III) from aqueous solution.

Hydroxyapatite/NiFe2O4 superparamagnetic composite: Facile synthesis and adsorption of rare elements

A magnetic hydroxyapatite composite (CaHAP/NF) derived from calcium hydroxyapatite [Ca10(PO4)6(OH)2] and nickel ferrite [NiFe2O4] was successfully synthesized by a coprecipitation method. The synthesized composite was characterized using Fourier transform infrared spectroscopy (FT–IR), X-Ray diffractometer (XRD), thermogravimetric differential thermal analysis (TG-DTA), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). Results clarify that the composite is a crystalline in nature, thermally stable up to 800 °C and possesses a high porous structure. The synthesized CaHAP/NF composite is a superparamagnetic material easily separated from aqueous solutions and would dissociate to some extent in strongly acidic conditions. The synthesized material was successfully applied as a solid phase for separation of Eu(III) and Tb(III) ions from aqueous solutions. The effect of various parameters (e.g. solution pH, equilibrium time and ionic strength) on sorption process was studied in static conditions. The synthesized sorbent could be considered as an efficient candidate for separation and recovery of Eu(III) and Tb(III). The sorption process was very fast initially, reached equilibrium within 6 h of contact and independent of ionic strength. The maximum sorption capacity values were 137.35 and 130.43 mg g–1 for Eu(III) and Tb(III), respectively. Desorption of Eu(III) and Tb(III) from loaded sample was studied using various eluents and maximum recovery was obtained using FeCl3 and EDTA solutions. More importantly, both FeCl3 and EDTA were individually applied as eluents in chromatographic separation of Eu(III) and Tb(III) in CaHAP/NF packed column and the best separation results were obtained by EDTA.

Carbon Cloth Supported Nano-Mg(OH)2 for the Enrichment and Recovery of Rare Earth Element Eu(III) From Aqueous Solution.

Nano-Mg(OH)2 is attracting great attention as adsorbent for pre-concentration and recovery of rare earth elements (REEs) from low-concentration solution, due to its superior removal efficiency for REEs and environmental friendliness. However, the nanoparticles also cause some severe problems during application, including aggregation, blockage in fixed-bed column, as well as the difficulties in separation and reuse. Herein, in order to avoid the mentioned problems, a carbon cloth (CC) supported nano-Mg(OH)2 (nano-Mg(OH)2@CC) was synthesized by electrodeposition. The X-ray diffraction and scanning electron microscopy analysis demonstrated that the interlaced nano-sheet of Mg(OH)2 grew firmly and uniformly on the surface of carbon cloth fibers. Batch adsorption experiments of Eu(III) indicated that the nano-Mg(OH)2@CC composite maintained the excellent adsorption performance of nano-Mg(OH)2 toward Eu(III). After adsorption, the Eu containing composite was calcined under nitrogen atmosphere. The content of Eu2O3 in the calcined material was as high as 99.66%. Fixed-bed column experiments indicated that no blockage for Mg(OH)2@CC composite was observed during the treatment, while the complete blockage of occurred to nano-Mg(OH)2 at an effluent volume of 240 mL. Moreover, the removal efficiency of Mg(OH)2@CC was still higher than 90% until 4,200 mL of effluent volume. This work provides a promising method for feasible application of nanoadsorbents in fixed-bed process to recycle low-concentration REEs from wastewater.

Damage recovery and dopant migration of Eu+ ion implanted KTiOAsO4 crystals

Damage formation and annealing of Eu implanted KTiOAsO4 crystals is investigated. Ion implantation was done with 400 keV Eu2+ ions and an ion fluence of 5 × 1015 ions/cm2 at room temperature. The damage of as-implanted and annealed samples was analysed by Rutherford backscattering spectrometry in channelling configuration using 2.1 MeV He+ ions. After implantation, a thick RBS-amorphous layer is obtained. The damage in the Eu2+ implanted KTiOAsO4 layer decreases significantly after annealing at 700° C for 30 min in Ar atmosphere. Interestingly, the Eu peak firstly migrated to the surface after annealing at 600° C for 30 min, and then appeared narrower after annealing at 700° C for 30 min. Furthermore, arsenic loss by evaporation and titanium enrichment at the surface are observed during the annealing process.

Sorption behavior of Eu(III) from an aqueous solution onto modified hydroxyapatite: kinetics, modeling and thermodynamics

ABSTRACTNano-pore hydroxyapatite (HAP) was prepared using physical activation of raw and chemically modified [using Acid; HNO3 (HAPA) or Base; NaOH (HAPB)] bone char (BC) by heating at 900°C for 1 hr to obtain HAP9, HAPA9 and HAPB9, respectively. Investigation the effects of thermal and chemical treatment of prepared nano-hydroxyapatite on elemental analysis, FTIR, scanning electron microscopy, surface area and consequently, the sorption behavior of Eu (III) ions onto the prepared nano-pore hydroxyapatite. Batch adsorption technique was used and the obtained results revealed that the optimum pH = 5.0. The % removal of europium (III) using HAPA9 and HAPB9 reach to 100% within 15 min, while HAP9 after 180 min and the pseudo-second-order was found to be fit to the experimental data. According to Langmuir model, the maximum sorption capacities (qm) were 123.8, 384.9 and 74.2 mg g−1 for HAP9, HAPA9 and HAPB9, respectively. The reaction is spontaneous according to ΔG° value. HCl (0.5 M) was the most efficient desorbing agent for recovery of Eu(III) and regeneration of adsorbents. Finally, nano-pore hydroxyapatite (HAP) was low cost and very effective adsorbent for sorption or recovery of Eu(III) from aqueous solutions and remediation of environmental pollution.

ChemInform Abstract: Complete Recovery of Eu from BaMgAl10O17:Eu2+ by Alkaline Fusion and Its Mechanism.

AbstractEu is completely recovered from BaMgAl10O17:Eu2+ (I) by disintegration via alkaline fusion using NaOH and (I) in a 1:1 mass ratio for ball milling followed by heating (Fe crucible, 150‐375 °C, 2 h).

Complete recovery of Eu from BaMgAl10O17:Eu2+ by alkaline fusion and its mechanism

An environmentally friendly and efficient process for recycling waste phosphors has been developed.

Process development for the recovery of europium and yttrium from computer monitor screens

This work describes the development of a process for the recovery of Eu and Y from cathode ray tubes (CRTs) of discarded computer monitors with the proposition of a flow sheet for the metals dissolution. Amongst other elements, europium and yttrium are presented in the CRTs in quantities – 0.73 w/w% of Eu and 13.4 w/w% of Y – that make their recovery worthwhile. The process developed is comprised of the sample acid digestion with concentrated sulphuric acid followed by water dynamic leaching at room temperature. In the CRTs, yttrium is present as oxysulphide (Y2O2S) and europium is an associated element – Y2O2S:Eu3+ (red phosphor compound). During the sulphuric acid digestion, oxysulphide is converted into a trivalent Eu and Y sulphate, in solid form, with the liberation of H2S. In the second step, metals are leached from the solid produced in the acid digestion step by dynamic leaching with water. This study indicates that a proportion of 1250 g of acid per kg of the sample is enough to convert Eu and Y oxysulphide into sulphate. After 15 min of acid digestion and 1.0 h of water leaching, a pregnant sulphuric liquor containing 17 g L−1 Y and 0.71 g L−1 Eu was obtained indicating yield recovery of Eu and Y of 96% and 98%, respectively. Both steps (acid digestion and water leaching) may be performed at room temperature.

Studies on the Radiochemical Degradation of Tetraethylhexyl Diglycolamide and Ethylhexylphosphoric Acid in n-Dodecane Solution

The organic solvent phase composed of N,N,N’,N’-tetra-2-ethylhexyl diglycolamide (TEHDGA) and bis(2-ethylhexyl)phosphoric acid (HDEHP) in n-dodecane (n-DD) is regarded as a promising candidate for single-cycle separation of americium (III) from high-level liquid waste. The radiochemical degradation of a solution of TEHDGA + HDEHP/n-DD was investigated by irradiating the solvent to various absorbed dose levels of γ-radiation. The neat extractants or a solution of extractants in n-dodecane were irradiated in the presence and absence of nitric acid. The degree of degradation was assessed by measuring the variation in the extraction behavior of Am(III), Eu(III) and other metal ions in irradiated solvent systems. The distribution ratio of americium and europium decreased with increase of absorbed dose. The presence of n-dodecane enhanced the radiolytic degradation of the solvent; however, the role of nitric acid during degradation was insignificant. The recovery of Am(III) and Eu(III) from the irradiated solvent system was studied. The recovery of Am(III) was quantitative in 3 contacts; however, the separation factor of Eu(III) over Am(III) during stripping decreased marginally with increase of absorbed dose.

Separation and Recovery of Eu(III) and Y(III) with Solvent Impregnated Resin Coated by Crosslinked Chitosan

Separation of europium (Eu3+) and yttrium (Y3+), using a solvent impregnated resin (SIR) containing 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester, coated by water-soluble chitosan crosslinked by glutaraldehyde, was investigated. Coating of the SIR successfully suppressed leakage of the extractant during adsorption processing. Adsorption of Eu3+ with both coated and uncoated SIRs was progressed with Langmuir mechanism, and the maximum adsorption amount of Eu3+ at equilibrium pH = 2.27 was 0.294 mol/kg with coated SIR and 0.310 mol/kg with uncoated SIR. Decrease in the maximum adsorption amount by coating SIR with polymer can be suppressed rather than the other coated SIRs previously reported. The coated SIR was then applied to column separation of Eu3+ and Y3+. Complete separation of the metals could be achieved by gradient elution with a gradual increase in the concentration of a dilute nitric acid. The coated SIR could also be reused for repeated adsorption-elution processing.