Rare Earth Sm Research Articles

Separation and solvent extraction of rare earth elements (Pr, Nd, Sm, Eu, Tb, and Er) using TBP and Cyanex 572 from a chloride medium

In this study, synergistic effect of Cyanex 572 mixed with TBP on the extraction and separation of six selected light, medium and heavy rare earth elements (REE), namely neodymium (Nd), praseodymium (Pr), samarium (Sm), europium (Eu), terbium (Tb), and erbium (Er), from the chloride medium was investigated. The results demonstrated that sole TBP is not a suitable extractant for the separation of the REEs from the chloride media. However, Cyanex 572 was identified as a suitable extractant for the separation of heavy REEs, Er, and Tb. At initial pH (pHi) of 1.5, the mixture of 25% TBP + 75% Cyanex 572 extracted about 70% and 85% of Er and Tb, respectively. The separation factor (SF) results of some couples were noteworthy: SFEr/Pr = 30.08, SFEr/Nd = 29.95, SFTb/Pr = 12.22, SFTb/Nd = 12.16, SFEr/Sm = 9.96. Furthermore, the extraction mechanism of these two heavy REEs was studied using slope analysis and Fourier transform infrared measurements (FT-IR). The results showed that Er and Tb were extracted as ErCl2R(HR)3TBP and TbCl2R(HR)3TBP complexes (presumably R and HR refers to Cyanex 572), respectively. The FT-IR spectra confirmed these obtained results qualitatively.

Electrochemical Recovery and Behaviors of Rare Earth (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb) Ions on Ni Sheets.

The electrochemical behaviors of rare earth (RE) ions have extensively been studied because of their high potential applications to the reprocessing of used nuclear fuels and RE-containing materials. In the present study, we fully investigated the electrochemical behaviors of RE(III) (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb) ions over a Ni sheet electrode in 0.1 M NaClO4 electrolyte solution by cyclic voltammetry between +0.5 and −1.5 V (vs. Ag/AgCl). Amperometry electrodeposition experiments were performed between −1.2 and −0.9 V to recover RE elements over the Ni sheet. The successfully RE-recovered Ni sheets were fully characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and photoluminescence spectroscopy. The newly reported recovery data for RE(III) ions over a metal electrode provide valuable information on the development of the treatment methods of RE elements.

Rare earth insitu-doped ZIF-67 derived N doped C encapsulated Sm2O3/Co nanoparticles as excellent oxygen reduction reaction catalyst for Al-air batteries

A novel carbon coupled rare earth Sm doped zeolitic imidazolate framework-67 (ZIF-67) derived Sm2O3–Co/NEC300J electrocatalyst with an encapsulated structure was prepared via a composite synthetic strategy, which owns highly dispersed active sites and high conductivity. The introduction of Sm2O3 significantly improves the oxygen reduction reaction (ORR) electrocatalytic performance due to the strong synergistic effect between promoter Sm2O3 and guest Co species, in which the onset potential, half-wave potential and limiting current density are all improved compared to pristine ZIF-67 derived Co/NC. The introduction of Ketjen black EC300J (EC300J) brings high conductivity, so the precursor can be calcined under relative low temperature, and huge highly dispersed ORR active sites are created, meanwhile the EC300J offers a restricted pyrolysis environment to form carbon encapsulated structure. Therefore, Sm2O3–Co/NEC300J exhibits excellent activities and stability compared to Sm-doped ZIF-67 derived Sm2O3–Co/NC. For practical application, the designed Al-air battery with an air-cathode catalyst of Sm2O3–Co/NEC300J achieves the specific capacity of 1588 mAh·g-1Al at the discharge current density of 20 mA·cm−2, which almost equals to that of Pt/C. Furthermore, the peak power density and discharge voltage of Sm2O3–Co/NEC300J based Al-air battery are much higher than the Sm2O3–Co/NC, Co/NC and Pt/C counterparts.

Hazardous motherboards: Changes in metal contamination related to the evolution of electronictechnologies.

Proper management of electronic waste (e-waste) represents significant economic and environmental challenges because of the tremendous quantity of e-waste, the potential of extracting precious metals from recyclable electronics, and the risks of environmental contamination with a variety of toxic compounds. This study focused on the leaching potential of 57 elements from central processing unit mainboards manufactured over time (1980s-2010s) using river water at different pHs as an environmentally-relevant extractant. The exposure time was set to one week. The calculated contamination factors allowed classification of the elements released from mainboards into five groups with increasing leachability and thus environmental concerns. Also, the results demonstrated a changing nature of e-waste related to the technologies employed and the transition of metal contamination signatures from these electronics; newer computer mainboards have a lower risk of Pb and Sn leaching but a greater release of Li, Sb, and a few rare earth elements (Sm, Eu, Dy). These specific patterns of elemental release could become powerful geochemical forensic tracers of improper recycling activities of e-waste in the environment. Most studies until now have investigated just a few key contaminants, despite the cocktail of pollutants contained in electronics. Therefore, a full assessment of the leaching potential of pollutants from non-properly recycled e-waste and further ecotoxicological studies are timely needed.

Protonated g-C3N4 cooperated with Co-MOF doped with Sm to construct 2D/2D heterojunction for integrated dye-sensitized photocatalytic H2 evolution

A dye-sensitive photocatalytic H2 evolution reaction (HER) system with photogenerated carrier directed conduction was constructed. The protonated g-C3N4 combines with the sheet-like Co MOF to form a 2D/2D heterojunction via electrostatic self-assembly. The protonated g-C3N4 and 2D Co-MOF directionally adsorb Eosin Y (EY) and triethanolamine (TEOA) molecules through hydrogen bond and complexation to achieve a whole photocatalytic system. The integral structure effectively facilitates the utilization of dye sensitizer and hole sacrificial agent to achieve the effective and stable photocatalytic H2 evolution capacity. The photocatalytic hydrogen evolution rate of g-C3N4 after protonation is 1.88 times as high as that of the original g-C3N4. On the basis of 2D/2D heterojunction, Co MOF is doped with rare earth element Sm. The 4f electrons and the difference valences (Sm3+ and Co2+) further suppress the reorganization of photogenerated excitons to achieve highly efficient photocatalytic HER. The directional coupling of sensitizer and electron sacrificial agent combined with rare earth element doping makes the photocatalytic HER rate of the composite material reached 73.42 μmol.h−1 within 5 h under simulated sunlight.

Tuning microwave absorption properties of melt-spun FeSiCo alloys based on the addition of rare earth Sm

The effects of Sm-doped on microwave absorption properties of melt-spun FeSiCo alloys were studied in this paper. The composite alloys were characterized by XRD, SEM, VSM, and vector network analysers (VNA). The phase identification shows that only α-Fe(Co) phase was observed for all samples. SEM images have revealed that the morphology of all powders were flaky shape with different particle size. The values of saturation magnetization (Ms) and coercivity (Hc) increased with the increase of Sm-doping content. In addition, the minimal reflection loss ((RL)min) is − 7.96 dB at 1.7 GHz with the thickness of 3 mm for Sm1Fe79Si10Co10 sample. The results reveal that the addition of Sm can improve the microwave absorption property of FeSiCo alloys.

Point defect engineering and machinability in n-type Mg3Sb2-based materials

Approaching practical thermoelectric devices require high-performance and machinable thermoelectric materials. However, the currently available materials are usually brittle. In this work, Nd-doped Mg3Sb2-based compounds exhibit not only excellent thermoelectric performance but also superior machinability. Mg3.2Nd0.03Sb1.5Bi0.5 exhibits a high power factor of 20.6 μW cm−1 K−2 at 725 K and a peak zT of 1.8, which mainly originates from the increased n of ~8 × 1019 cm−3 by Nd/Mg substitutional defects. Defect calculations predict that other rare earth elements (Sm, Gd, Tb, Dy and Ho) have the same effect as Nd on Mg3Sb2 and the predicted highest achievable electron concentrations at 700 K are ~1020 cm−3. The measured hardness, Young's modulus and fracture toughness of Mg3.2Nd0.03Sb1.5Bi0.5 are 1.1 GPa, 49.8 GPa and 1.4 MPa m1/2, respectively. In addition, the sample can be easily machined into the dog-bone shape with external thread at both ends, indicating the excellent machinability of Mg3Sb2-based materials. This work suggests a bright future of Mg3Sb2-based thermoelectric materials for practical applications and device fabrication.

New investigation of nanosized co-doped Gd-Sm anatase TiO2 structural, magnetic, optical, and first-principles study

For the time we investigated the structural, optical and magnetic properties of (Sm, Gd) co-doped TiO2 anatase nanoparticles, in addition to Sm-doped TiO2 anatase nanoparticles using sol–gel method. The X-ray diffraction confirmed the single phase of tetragonal anatase with space group I41/amd, where the crystallite size was found 7.2 nm and 8.8 nm for Ti0.99Sm0.01O2 and Ti0.99Sm0.005Gd0.005O2, respectively. The Fourier-transform infrared spectra showed the basic absorption bands in tetragonal anatase structure with a stretching vibration around 500 cm−1 assigned to Ti–O–M, M = (Gd, Sm). Raman spectroscopy demonstrated the presence of the six active vibrational modes for anatase TiO2. Scanning electron microscopy analysis revealed that the particles are spherical in nature and agglomerated. Energy-dispersive X-ray spectroscopy confirmed the high purity of the as-prepared materials. The UV–VIS analysis showed absorption in visible range, due to the electronic transition, which has been confirmed theoretically, also a slight decrease in the band gap was noticed compared to the pure TiO2 anatase. The magnetic measurements reveal the existence of weak ferro or ferrimagnetic behavior. In this work, it is the first time that experimental and theoretical results prove that rare earth ions are incorporated into the sites of the TiO2 lattice without the formation of separate phases. In addition, the experimental work carried out has revealed the importance of surface area, crystallinity, light absorption, the presence of oxygen vacancies and structural defects on the magnetic and more particularly optical properties with the highlighting of the intermediate energy level between the valence and conduction bands. This study was complemented by first-principles calculations to investigate the effects of doping anatase TiO2 with the rare-earth elements Sm and Gd on its structural, optical and magnetic properties.

Accumulation of dysprosium, samarium, terbium, lanthanum, neodymium and ytterbium by Arthrospira platensis and their effects on biomass biochemical composition

The growth of Arthrospira platensis and physiological changes in biomass under the effects of six rare earth elements Dy, Sm, Tb, La, Nd and Yb were evaluated. Elements were tested by three concentrations of 10, 20 and 30 mg/L. According to neutron activation analysis data A. platensis's accumulation capacity toward studied elements changes in the following order of La > Dy > Nd > Sm > Yb > Tb. The results show that Dy and La ions stimulate biomass growth and Yb ions inhibit it, while Sm, Tb and Nd ions do not affect biomass accumulation. The contents of proteins and chlorophyll a are not affected by the presence of rare earth elements in the cultivation medium. Studied elements affect to different extents carbohydrates, phycobilins, β-carotene, lipids and MDA contents in spirulina biomass. Changes in the antioxidant activity under applied metal loads reveal a moderate stress in exposed A. platensis. Cyanobacterium A. platensis can be successfully used for bioremediation of natural water contaminated with REEs as well as REEs recovery from low polluted industrial effluents.

Recovery of rare-earth elements from nitrate solutions using polyethylene glycol 1500

A new extraction system based on polyethylene glycol 1500 and NaNO3 was proposed for the recovery of light rare-earth elements (Ce, La, Nd, Pr, and Sm) from aqueous solutions. The equilibrium distribution coefficients and degrees of extraction of CeIII, LaIII, NdIII, PrIII, and SmIII in the proposed aqueous two-phase system were found. The dependences of the quantitative characteristics of rare-earth element extraction on the temperature, initial metal concentration, and acidity of the medium were obtained. The degree of extraction of the metal ions within one step was shown to exceed 60% at the phase ratio 1:1 without introducing additional complexation agents.

Distribution, sources and ecological risk of trace elements and polycyclic aromatic hydrocarbons in sediments from a polluted urban river in central Bangladesh

To assess the spatial and layer-wise distributions of 26 elements (Na, Al, Mg, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Sb, Co, Ba, Zn, Rb, Cs, La, Ce, Sm, Eu, Yb, Ta, Hf, Th and U) as well as the spatial distributions of polycyclic aromatic hydrocarbons (PAHs) in a polluted urban river (Turag, Bangladesh), benthic sediment samples from 11 different sampling stations were analyzed. Concentrations of Ti, Cr, Mn, Zn, Rb and Cs ranged from 2330 to 5490, 23–116, 186–4298, 34–7345, 77–186 and 2.19–12.0 μg.g−1(dw), respectively, whereas concentrations of ∑PAHs ranged from 45.8 to 1901 with an average value of 432 μg.kg−1(dw) in surface sediments. Geo-accumulation index, enrichment factor and pollution load index were used to assess the contamination level. Among the 26 elements, Zn is identified as the major elemental contaminant which shows significant layer-wise variations (RSDs: 21.7–221 %) at all sampling sites. Similarly, Cr, Mn, Ti, V, Fe and Co show layer-wise variation in some specific sampling sites which invokes variable contamination flux over the industrialization and/or urbanization period. Principal component analysis (PCA) and correlation study ascertained several anthropogenic sources for heavy metal contaminations. Although rare earth elements (La, Ce, Sm, Eu and Yb) seem to have crustal origin, their layer-wise variations are assumed to represent the sediment response toward the pollution load. Integrated study based on the diagnostic ratios and PCA depicted that pyrolytic origins mostly govern the PAHs distributions. Sediments quality guidelines (SQGs) indicated that the highest potential ecological risks occurred for Zn and fluorene at some specific sampling sites.

Transparent and conductive Sm-doped SrSnO3 epitaxial films

Abstract Perovskite-structured (SmxSr1-x)SnO3 (SSSO) films with x = 0–0.15 were epitaxially grown on LaAlO3(001) substrates by pulsed laser deposition, and the microstructure, transport and optical properties were investigated in detail. X-ray diffraction results show that the lattice constants gradually decrease with the Sm content increasing. Atomic force microscopy images confirm that all the films possess a smooth surface with low surface roughness. X-ray photoelectron spectroscopy measurements prove the existence of Sm3+ state in the doped SSSO films. Hall-effect measurements show that the film at x = 0.06 has the lowest room-temperature resistivity of 5.91 mΩcm and the highest electron mobility of 14.8 cm2/Vs. Temperature-dependent resistivity curves were fitted and explained by weak localization effect and e--e- interactions at low temperatures for films at x = 0.04 to 0.10. Optical transparency of all the films is more than 70% in the wavelength range from 600 to 1800 nm, and the band gaps increase gradually from 4.27 to 4.60 eV with increasing Sm content to 0.06, which can be ascribed to Burstein-Moss effect. Furthermore, the insertion of pure SrSnO3 buffer layer between the substrate and the SSSO film considerably reduces the density of dislocations, thereby leading to the improved electrical transport property. All these results bring rare-earth element Sm a step closer to optoelectronic applications of all-perovskite transparent and conductive oxides.

Synthesis of Enantiopure Lanthanide Complexes Supported by Hexadentate N,N'-Bis(methylbipyridyl)bipyrrolidine and Their Circularly Polarized Luminescence.

We report the synthesis of lanthanide complexes supported by enantiopure N,N'-bis(methylbipyridyl)bipyrrolidine and subsequent characterization through luminescence studies. Complexes of this ligand with the visibly emissive lanthanides Sm, Eu, Tb, and Dy are luminescent (ϕf of ≤0.32) and demonstrate strong preferential emission of circularly polarized light in all four cases (|glum| of ≤0.26). Notably, all four possess at least one transition with a |glum| of >0.2, and the strongest preferential emission is measured from the complexes of Sm and Dy.

Effects of Sm-doping on microstructure, magnetic and microwave absorption properties of BiFeO3

In this paper, polycrystalline samples of Bi1–xSmxFeO3 (x = 0, 0.05, 0.1, 0.15) were successfully synthesized by sol-gel method. The effects of Sm concentration on the crystal structure, morphology, chemical states, magnetic properties and microwave absorption performance were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), a vibrating sample magnetometer (VSM) and a Vector network analyzer (VNA), respectively. The results show that the rare earth Sm doping causes the crystal structure to change. When x ≤ 0.1, Bi1–xSmxFeO3 is the distorted rhombohedral structure with space group R3c. With the increase of Sm doping amount to x = 0.15, the phase structure of Bi1–xSmxFeO3 changes from rhombohedral structure to cubic structure with the space group Pm3¯m. The particle size decreases with the increase of the Sm doping amount. The analysis results show that Sm doping can effectively reduce the oxygen vacancies and significantly improve its magnetic properties. The results exhibit that moderately doped rare earth Sm element can effectively improve microwave absorption properties of Bi1–xSmxFeO3 powders. When Sm doping amount of x is 0.1, the Bi0.9Sm0.1FeO3 compound has good microwave absorption performance, and the minimum reflection loss value of Bi0.9Sm0.1FeO3 powder reaches about −32.9 dB at 11.7 GHz, and its effective absorption bandwidth (RL < −10 dB) is 2.6 GHz with the optimal matching thickness of 2.0 mm.

Magnetic characteristics and optical band alignments of rare earth (Sm+3, Nd+3) doped garnet ferrite nanoparticles (NPs)

Yttrium iron garnet (YIG) nanoparticles (NPs) doped with rare earth (RE) metal ions (Y2.5Sm0.5Fe5O12, Y2.5Nd0.5Fe5O12) were successfully synthesized by sol-gel auto combustion approach. The cubic crystalline structure and morphology of the prepared garnet ferrite NPs were analyzed by X-ray diffractometer (XRD) and field emission scanning electron microscopy (FESEM). The cubic crystalline garnet phase of the synthesized YIG, Sm-YIG and Nd-YIG samples was successfully achieved at 950 °C sintering temperature. The force constant and absorption bands were estimated by using Fourier transform infrared spectroscopy (FTIR). The doping effect of RE metal ions on the chemical states of YIG were examined by x-ray photoelectron microscopy (XPS). The valence band (from 12.63 eV to 13.22 eV), conduction band (from 10.89 eV to 11.34 eV) edges and optical bandgap values of RE doped YIG samples were calculated using UV–Vis spectroscopy and ultraviolet photo electron spectroscopy (UPS). The magnetic analysis of the prepared NPs was studied using vibrating sample magnetometer (VSM). The XPS analysis of RE doped YIG samples exhibit the existence of RE (Sm+3, Nd+3) contents on the surface of YIG ferrite by decreasing the oxygen lattice in garnet structure. The optical bandgap (from 1.74 eV to 1.88 eV) explains the semiconducting nature of the synthesized NPs. The UPS results confirm the valence band position of YIG doped samples. The saturation magnetization and remanence of RE doped garnet ferrite samples increased from 13.45 to 18.83 emu/g and 4.06–6.53 emu/g, respectively.

Effects of various rare-earth additives on the sintering and transmittance of γ-AlON

Several rare earth elements (Sc, La, Pr, Sm, Gd, Dy, Er, and Yb) were evaluated to develop a sintering additive for transparent γ-AlON. After adding 0.2 wt. % of each of the rare earth additives to the α-Al2O3 and AlN starting material, hot pressing was performed at 1850 °C for 1 h under 20 MPa as a screening test, whereby the γ-AlON with Pr-nitrate showed the highest transmittance of 60.4 % at 632 nm. Two-step pressureless sintering was conducted as a separate test for the same starting material after adjusting the amount of Pr-nitrate to 0, 0.1, or 0.2 wt. % to enhance transmittance. The γ-AlON with 0.1 wt. % Pr-nitrate showed the highest transmittance of 80.36 % after 1st and 2nd sintering steps at 1610 and 1940 °C, respectively, indicating that Pr can be an alternative sintering additive to conventional Y2O3, MgO, and La2O3 for the fabrication of transparent γ-AlON.

Sol-Gel Synthesis of NiO/CuO Nanocomposites for Uptake of Rare Earth Elements (Ho, Yb, and Sm) from Aqueous Solutions

NiO/CuO nanocomposites are synthesized successfully by sol-gel method and employed for the uptake of rare earth elements (Ho, Yb, and Sm) from aqueous solutions. NiO/CuO nanocomposites have been characterized by FT-IR, SEM-EDAX, and X-ray diffraction (XRD). Results of XRD analysis show the crystal structure of NiO/CuO with average sizes between 50–80 nm. The SEM photographs show granular and plate morphology of nanoparticles with high uniformity. FTIR spectra show a broad band at 480–486 cm–1, which are corresponded to the Cu–O bond in the CuO structure and a broad band in the range of 440–470 cm–1, this band is assigned to the Ni–O bond stretching vibrations. Various parameters including pH, contact time; initial concentration and temperature were optimized to achieve maximum adsorption capacity. The adsorption efficiency of Yb(III), Sm(III), and Ho(III) are 97, 96, and 96% on NiO/CuO-500 and 92, 94 and 93% on NiO/CuO-800, respectively, under room temperature, pH 5 and 300 min. The adsorption kinetics of Ho(III), Yb(III), and Sm(III) have been described by pseudo-first order mechanism. The thermodynamics studies confirm that the adsorption is exothermic. The results indicate that the nanocomposite is an efficient adsorbent with good adsorption capacity for Ho(III), Yb(III), and Sm(III).

Giant current performance in lead-free piezoelectrics stem from local structural heterogeneity

Piezoelectric materials, which convert mechanical vibration energy into electric energy, are essential for vibration energy harvester. Nevertheless, the piezoelectric energy harvesting also encounters the bottleneck that piezoelectric materials generally produce only micro scale current due to its high impedance. In this work, the developed lead-free (Ba0.85Ca0.15)0.9985Sm0.001(Ti0.9Zr0.1)O3 (BCSm0.001TZ) piezoelectric ceramic possesses both high piezoelectric charge constant and low impedance, boosting its energy harvesting performance: an extremely high short-circuit current (60 µA) and large power density (2.1 µW/mm3) in a cantilever-type energy harvester, which is superior to those of other reported ones. Due to the giant current performance, the related charging speed of BCSm0.001TZ energy harvester possessed ~100% enhancement relative to the non-doped counterpart. Electrical property measurement and nanostructure observation revealed that the outstanding electromechanical properties as well as energy harvesting performances in BCSm0.001TZ ceramic benefits from a complex domain architecture and low concentration of defect, which is closely associated with the local structural heterogeneity induced by the rare-earth Sm doping. This work provides a new important paradigm for developing high-performance viable green energy materials and devices, especially for the fast recharging microelectronic storage devices in wireless sensor network.

Effect of rare earth (Sc, Y, La, Sm and Gd) doping on mechanical and thermodynamic properties of Al12Mg17 intermetallic compounds

The structural, electronic, mechanical and thermodynamic properties for [Formula: see text] and [Formula: see text] (RE = Sc, Y, La, Sm and Gd) compounds have been calculated by first-principles theory. The obtained structural parameters and elastic constants of two kinds of doped [Formula: see text] are compared with some theoretical and experimental data. The electronic structure analysis, such as density of states, explains the bonding character of Al–Mg–RE. All the doped [Formula: see text] are influenced by the high-energy electrons directly. Furthermore, the basic mechanical properties which are derived from the elastic constants and the thermal stability of doped [Formula: see text] are discussed. The predicted brittleness of [Formula: see text] and [Formula: see text] is consistent with the available experiments.

Silver(I)-selective electrodes based on rare earth element double-decker porphyrins

Various double-decker porphyrins accommodating rare earth elements (Sm, Tb, Y) were investigated as ionophores in potentiometric ion sensors. The studied ion-selective electrodes based on double-decker porphyrins were primarily selective to Ag+ ions. The experimentally derived selectivity coefficients were compared to theoretical predictions based on density functional theory (DFT) calculations of the metal-binding energies (ΔE) of double-decker porphyrin-metal ion complexes. Although DFT calculations were performed in vacuo, without taking into account ion-solvent and ion-membrane interactions, this computational approach showed relatively good correlation with the experimentally observed selectivity patterns of the ion-selective electrodes. Thus, DFT calculations were found to be a useful predictive tool when designing new ionophores for ion-selective electrodes.