Journal of Rare Earths最新文献

{"title":"La3+ doping-induced enhancement of dielectric performance in CdCu3Ti4O12 ceramics","authors":"Sirawit Promsai, Udomsilp Pinsook, Jakkree Boonlakhorn, Pornjuk Srepusharawoot","doi":"10.1016/j.jre.2025.10.011","DOIUrl":"10.1016/j.jre.2025.10.011","url":null,"abstract":"<div><div>This study explores the structural, microstructural, electrical, and dielectric properties of Cd<sub>1–3<em>x</em>/2</sub>La<sub><em>x</em></sub>Cu<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub> ceramics (<em>x</em> = 0, 0.025, 0.05 mol) synthesized via the solid-state reaction method, using both experimental and theoretical approaches. X-ray diffraction analysis confirms the formation of a main structure of CaCu<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub> in La<sup>3+</sup>-doped CdCu<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub>. Microstructural study reveals significant grain growth in La<sup>3+</sup>-doped CdCu<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub> samples, likely due to the liquid phase sintering mechanism caused by excess Cu resulting from La<sup>3+</sup> substitution, as supported by energy dispersive spectroscopy analysis. La<sup>3+</sup> doping significantly enhances the dielectric permittivity, particularly at low frequencies. La<sup>3+</sup>-doped samples exhibit dielectric permittivity of approximately 1 × 10<sup>5</sup>, compared to approximately 10<sup>4</sup> for undoped CdCu<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub>. Additionally, the doped samples show a low loss tangent of 0.037–0.050. This increase is attributed to space charge polarization and the formation of oxygen vacancy, supporting the internal barrier layer capacitor (IBLC) model. The <em>x</em> = 0.025 and 0.05 mol samples show the most stable dielectric property across −70 to 100 °C. Impedance spectroscopy confirms the IBLC structure. Impedance spectroscopy also indicates the impact of La<sup>3+</sup> doping on the improved grain boundary response. X-ray photoelectron spectroscopy (XPS) indicates mixed valence states, namely Cu<sup>+</sup>/Cu<sup>2+</sup> and Ti<sup>3+</sup>/Ti<sup>4+</sup>. These defects promote electron hopping and enhance the dielectric response. Density functional theory (DFT) calculations confirm structural stability of <em>x</em> = 0 and 0.05, showing that oxygen vacancies are mainly induced by external factors rather than directly by La<sup>3+</sup> incorporation. Electron density analysis links the formation of Cu<sup>+</sup> and Ti<sup>3+</sup> to the presence of oxygen vacancy. Overall, the superior dielectric performance results from the interplay between intrinsic lattice characteristics and extrinsic defect contributions. La<sup>3+</sup> doping may also lead to the formation of insulating boundary phases, contributing to reduced loss tangent. The presence of oxygen vacancy in the La<sup>3+</sup>-doped CdCu<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub> structure leads to changes in the oxidation states from Cu<sup>2+</sup> and Ti<sup>4+</sup> to Cu<sup>+</sup> and Ti<sup>3+</sup>, respectively, through a charge compensation mechanism. oxygen vacancy tends to form away from La atoms, indicating that it is not directly caused by doping but rather by external processes such as sintering. These changes result in local charge rearrangements, which enhance th","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 10","pages":"Pages 3008-3020"},"PeriodicalIF":9.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149072186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Highly efficient selective separation of scandium and zirconium by 331 resin","authors":"Minyu Zhu,&nbsp;Yan Liao,&nbsp;Chunlin He,&nbsp;Huan He,&nbsp;Guowang Wei,&nbsp;Qiankun Wei,&nbsp;Jun Wu,&nbsp;Zhenhai Huang","doi":"10.1016/j.jre.2025.10.009","DOIUrl":"10.1016/j.jre.2025.10.009","url":null,"abstract":"<div><div>In the defense industry and high-tech fields, scandium (Sc) has become one of the most commercially valuable strategic resources due to its unparalleled performance and diverse applications. However, the effective separation of Sc(III) and Zr(IV) remains a significant challenge owing to their nearly identical ionic radii and chemical properties. This study introduces a novel approach for Sc-Zr separation using a commercially available weakly basic epoxy-based anion exchange resin (331 resin) in HCl medium. Unlike conventional adsorbents, the 331 resin exhibits significantly higher affinity for Sc(III) over Zr(IV), achieving a remarkable separation factor (SF_Sc/Zr) of 756.2 under weakly acidic conditions (pH 2), with excellent repeatability demonstrated over 5 cycles. The adsorption process follows the pseudo-second-order kinetic model and Langmuir isotherm model, with a saturated adsorption capacity of 63.99 mg_Sc/g at 318 K. Column experiments demonstrate practical applicability, achieving Sc(III) purity exceeding 99.99% using 1 mol/L NaCl eluent. The Thomas model perfectly predicts column behavior under the studied conditions, validating its inherent Langmuir-type adsorption kinetics and equilibrium assumptions (<em>R</em>² = 1 and low <em>χ</em>²). Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) analyses and density functional theory (DFT) calculations demonstrate that Sc(III) adsorption occurs through coordination with amine groups (–NH) on the resin, where these groups act as electron-donating ligands. This study provides a commercially viable, high-efficiency solution for strategic metal purification with significant implications for advanced material production.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 10","pages":"Pages 3031-3043"},"PeriodicalIF":9.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147331194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recent progress in photocatalytic green hydrogen production using rare earth metal-based photocatalysts","authors":"Ahmadullah Hridoy,&nbsp;Mohammad Tawfiqur Rahman,&nbsp;Rafid Bin Siddique,&nbsp;Md. Yeasin Arafat,&nbsp;A.K.M. Ahsanul Habib","doi":"10.1016/j.jre.2025.12.020","DOIUrl":"10.1016/j.jre.2025.12.020","url":null,"abstract":"<div><div>Photocatalytic procedures for green hydrogen production through water splitting processes now demand substantial study as a viable renewable technology to substitute fossil fuels. The combination of rare earth metals proves highly effective in photocatalysis because their light-absorption capabilities match well with unique electronic features while showing steady performance under irradiation. The paper offers an extensive summary of present developments in rare earth metal photocatalysts for artificial photosynthesis applications in clean hydrogen production. The materials demonstrate critical importance in solving the worldwide need for a sustainable energy supply. The review investigates how rare earth metals possess advanced electronic characteristics, which strengthen photocatalytic functioning as well as stability, and presents methods for preparation that include sol–gel processes, hydrothermal synthesis, and chemical vapor deposition production techniques. The article examines nano-structuring along with doping techniques and composite development, and band gap controller advances, which serve to boost solar illumination durability and photoactivity. Large-scale hydrogen production systems that integrate rare earth metal-based photocatalysts must have practical implementation examined in addition to economic efficiency and environmental impact analysis. A forward-looking analysis of rare earth metal-based photocatalyst development for artificial photosynthesis is presented in this review by examining new trends and research opportunities and technical hurdles to expect in the coming years, according to technological, environmental, and economic factors. The research highlights how rare-earth metal-based photocatalysts can serve as a medium to transform clean hydrogen production methods.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 10","pages":"Pages 2787-2815"},"PeriodicalIF":9.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149072205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Giant luminescence enhancement in Li2MSiO4:Eu2+ (M = Sr, Ba) via two-step synthesis and charge compensation","authors":"Chengyan Gao,&nbsp;Guojun Zhou,&nbsp;Yawen Deng,&nbsp;Qiufeng Shi,&nbsp;Lei Wang,&nbsp;Haijie Guo,&nbsp;Jianwei Qiao","doi":"10.1016/j.jre.2026.07.026","DOIUrl":"10.1016/j.jre.2026.07.026","url":null,"abstract":"<div><div>Eu²⁺-activated phosphors are prominent candidates for next-generation solid-state lighting, but their performance is often limited by incomplete Eu³⁺ reduction and poor thermal stability. Herein, we present a universal strategy combining a two-step synthesis with charge compensation to simultaneously stabilize Eu²⁺ centers and suppress parasitic Eu³⁺. Initially, M₂SiO₄:Eu²⁺ (<em>Pnma</em>) precursors were synthesized to promote effective Eu²⁺ incorporation. Subsequent P⁵⁺ co-doping induces charge-compensated substitution (Si⁴⁺→P⁵⁺). This structural evolution yields the target phosphor phases: the yellow-emitting Li₂SrSi_0.96P_0.04O₄:Eu²⁺ (<em>P</em>3₁21) and the green-emitting Li₂BaSi_0.96P_0.04O₄:Eu²⁺ (<em>P</em>6₃<em>cm</em>) with excitation/emission maxima at 394/580 and 365/520 nm, respectively. Importantly, the heterovalent substitution facilitates the Eu³⁺→Eu²⁺ reduction and optimizes the defect distribution. Consequently, the photoluminescence quantum yield (PLQY) is significantly enhanced from 26% to 78% for Li₂SrSi_0.96P_0.04O₄:Eu²⁺ and from 32% to 83% for Li₂BaSi_0.96P_0.04O₄:Eu²⁺, along with improved thermal stability (93.3%@450 K). Fabricated near-UV pumped white light-emitting diodes (LEDs) incorporating these phosphors demonstrate superior color rendering (<em>Ra</em> = 91.1) and stable electroluminescence across varying currents. The robust Eu²⁺ stabilization and charge compensation paradigm paves the way for rational design of high-performance phosphors for advanced lighting.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 10","pages":"Pages 2843-2851"},"PeriodicalIF":9.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149072222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Luminescence of garnet-structure NaLu2Ga3Ge2O12: Tb3+ green long afterglow phosphor for latent fingerprints and information encryption applications","authors":"Jiahui Zhang,&nbsp;Junhao Li,&nbsp;Linyun Zeng,&nbsp;Chunli Li,&nbsp;Wenjing Huang,&nbsp;Ziying Hong,&nbsp;Wenjia Xie,&nbsp;Liya Zhou,&nbsp;Mubiao Xie,&nbsp;Haiyong Ni,&nbsp;Xinguo Zhang","doi":"10.1016/j.jre.2026.01.001","DOIUrl":"10.1016/j.jre.2026.01.001","url":null,"abstract":"<div><div>In this work, a new garnet-type NaLu₂Ga₃Ge₂O₁₂: Tb³⁺ phosphor was successfully prepared by solid-state reaction, which exhibits strong green emission at 543 nm under 272 nm ultraviolet excitation with long-lasting afterglow (&gt;1200 s). Thermoluminescence (TL) curves reveal the existence of trap level with depth (0.367 eV), which plays a crucial role in charge carrier storage and release. The appropriate trap depth results in the long afterglow luminescence of NaLu₂Ga₃Ge₂O₁₂: Tb³⁺. This green phosphor can realize level I–III latent fingerprints on various substrates with high contrast and resolution. Mixing NaLu₂Ga₃Ge₂O₁₂: Tb³⁺ with commercial Y₂O₃: Eu³⁺ red phosphor, the information encryption is achieved, which displays different fluorescent information under sunlight, UV light and in the dark. This study provides a potential long afterglow green phosphor, which has good application prospects in the fields of latent fingerprints and information encryption.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 10","pages":"Pages 2860-2870"},"PeriodicalIF":9.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149072224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optically, magneto-dielectrically, and ferroelectrically modified Zn-Co-Cu-Ce/GNPs nanocomposites for dielectric energy storage applications","authors":"Atta Ur Rehman,&nbsp;Nasir Amin,&nbsp;Muhammad Ajaz-un-Nabi,&nbsp;Kiran Mehmood,&nbsp;Kashif Javaid,&nbsp;Mongi Amami,&nbsp;Lamia ben Farhat,&nbsp;Muhammad Imran Arshad","doi":"10.1016/j.jre.2026.02.019","DOIUrl":"10.1016/j.jre.2026.02.019","url":null,"abstract":"<div><div>This study explored the structural, optical, magneto-dielectric, ferroelectric, and dielectric energy storage behavior of Zn_0.5Co_0.25Cu_0.25Ce_0.037Fe_1.963O₄/graphene nanoplatelets (ZCCCF/GNPs) nanocomposites with varying GNPs content (0 wt% −5 wt%), synthesized via self-combustion followed by bath sonication. Structural analysis confirmed the spinel phase for all compositions, with ZCCCF/3.75 wt% GNPs exhibiting the largest crystallite size (57.90 nm) and improved crystallinity. Optical studies reveal a tunable energy bandgap (<span><math><mrow><msub><mi>E</mi><mi>g</mi></msub></mrow></math></span>), and find that <span><math><mrow><msub><mi>E</mi><mi>g</mi></msub></mrow></math></span> is 3.20 eV for the 3.75 wt% GNPs composite. Dielectric results show the maximum dielectric constant (<em>ε</em>′ = 22.60), low loss tangent (tan<em>δ</em> = 0.3), and maximum quality factor for the 3.75 wt% GNPs composite. Magnetic measurements indicate enhanced soft magnetic behavior, with maximum saturation magnetization (<em>M</em>_s) (155 A·m²/kg) and minimum coercivity (41 × 10⁻⁴ T). Ferroelectric analysis reveals an increase in polarization from 1.45 × 10⁻⁴ μC/cm² (ZCCCF) to 9.07 × 10⁻⁴ μC/cm² (3.75 wt% GNPs). The maximum energy density (3.99 × 10⁻⁴ mJ/cm³) also occurs at 3.75 wt% GNPs, while higher addition of GNPs (5 wt% GNPs) leads to efficiency recovery (<em>η</em> = 58%) but reduces energy storage due to increased dielectric losses. A comparative analysis with literature reports highlights the superior energy storage performance of ZCCCF/GNPs nanocomposites over conventional ferrites, making them promising candidates for dielectric energy storage applications.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 10","pages":"Pages 2986-2996"},"PeriodicalIF":9.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149072183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enzyme-based hollow downconversion nanoparticle for adaptively remodeling tumor acidic microenvironment and augmenting chemotherapy","authors":"Ziluo Peng,&nbsp;Na Cao,&nbsp;Sijia Chang,&nbsp;Lin Ji,&nbsp;Jing Zhou","doi":"10.1016/j.jre.2025.12.013","DOIUrl":"10.1016/j.jre.2025.12.013","url":null,"abstract":"<div><div>The abnormal metabolism of rapidly growing tumors can create an acidic tumor microenvironment (TME) that renders cancer cells resistant to chemotherapy. Adaptive pH-elevating nanoparticles that can maintain pH within a reasonable range would enhance the efficacy of chemotherapy. Here, pH-elevating, enzyme-based nanoparticles were constructed to remodel the TME and enhance tumor chemotherapy. Hollow NaBiF₄:Nd nanoparticles were engineered for drug delivery encapsulated paclitaxel and the urea substrate. They were coated with polyacrylic acid to confer acid responsiveness and were conjugated with urease on their surface. The resulting nanoparticles (BUPAU') effectively shift the pH from acidic to neutral or alkaline in aqueous environments. Concurrently, concurrent degradation of NaBiF₄:Nd provides real-time fluorescence feedback. Importantly, <em>in vitro</em> and <em>in vivo</em> data of the urease-urea system reveal that the nanoparticles effectively neutralize the acidic TME pH, sensitizing cancer cells to subsequent chemotherapy. Thus, compared to chemotherapy alone, the therapy by remodeling the TME significantly improves the antitumor effect of paclitaxel <em>in vitro</em> and <em>in vivo</em>. The findings demonstrate that chemotherapy sensitization could be synchronized by modulating TME pH.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 10","pages":"Pages 2997-3007"},"PeriodicalIF":9.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149072184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DNA-engineered nanoprobe with single-excitation dual-emission for ratiometric luminescence detection of mercury ions","authors":"Meiqing Liu,&nbsp;Wei Zang,&nbsp;Yesen Li,&nbsp;Yong Chen,&nbsp;Yun Zhang","doi":"10.1016/j.jre.2026.01.021","DOIUrl":"10.1016/j.jre.2026.01.021","url":null,"abstract":"<div><div>The development of single-excitation dual-emission (SEDE) ratiometric nanoprobes has emerged as a crucial strategy for the detection of heavy metal ions. In this study, a rare earth-based SEDE nanoprobe, designated ZG-Tb, was developed for rapid and sensitive Hg²⁺ detection through Tb³⁺ coordination onto guanine-rich hairpin DNA (GH5)-functionalized Cr-doped zinc gallogermanate nanoparticles. Upon 260 nm excitation, ZG-Tb exhibits two distinct emission bands: an intrinsic 696 nm emission from Z nanoparticles and a Tb³⁺-mediated 545 nm emission sensitized by surface-immobilized GH5. In the presence of Hg²⁺, competitive interaction between Hg²⁺ and Tb³⁺ for GH5 results in the selective quenching of the 545 nm emission while leaving the 696 nm emission unaltered. The ratiometric luminescence response (<em>I</em>₅₄₅/<em>I</em>₆₉₆) enables quantitative detection of Hg²⁺ within 1 min, with a linear range of 0–30 nmol/L and a detection limit of 1.45 nmol/L. The nanoprobe also shows reliable performance in drinking and tap water samples, underscoring its potential for practical applications.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 10","pages":"Pages 2871-2879"},"PeriodicalIF":9.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147890461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative analysis of hydrometallurgy and biosorption techniques for recovering rare earth elements from acid mine drainage at an abandoned coal mine","authors":"Meisam Peiravi,&nbsp;Partha Protim Bhowmik,&nbsp;Sonkorson Talukder Sabuj,&nbsp;Jia Liu","doi":"10.1016/j.jre.2026.02.004","DOIUrl":"10.1016/j.jre.2026.02.004","url":null,"abstract":"<div><div>Rare earth elements (REEs) are essential components in many modern technologies. Acid mine drainage (AMD) is a low-grade REE feedstock that could serve as a potential secondary source of REEs, though sustainable REE extraction techniques remain under development. This study compared a biosorptive approach with conventional hydrometallurgical recovery of REEs from AMD generated at an abandoned coal mine. In the hydrometallurgical method, solvent extraction with di-(2-ethylhexyl) phosphoric acid (D2EHPA) under natural AMD pH (∼2.5) recovers nearly all REEs from the aqueous phase, maintaining performance over three consecutive cycles. Stripping with 6 mol/L HNO₃ achieves high recovery of light (96.61% ± 4.32%), heavy (98.91% ± 4.51%), and total REEs (98.92% ± 4.52%) across three cycles. Subsequent oxalic acid precipitation yields total rare earth element (TREE) recoveries of 46.69% ± 0.73% and 56.17% ± 1.81% at pH 1.0 and pH 2.0, respectively. In comparison, biosorption using a <em>Serratia</em> spp. consortium achieves &gt;99% extraction of light, heavy, and total REEs within 90 min at pH 4.0 with a reduced biomass dosage. The biosorbent exhibits an irregular, rough, and porous surface containing numerous cavities and folds that serve as potential binding sites for metal ions. The experimental data fit well to the Freundlich isotherm, suggesting multilayer adsorption on a heterogeneous surface. Kinetic analysis indicates that the adsorption follows a pseudo-second-order model, with an equilibrium TREE adsorption capacity of 0.62 μg/mg biomass. Nitric acid stripping of REEs from the biomass preferentially recovers REEs over non-REE impurities. In contrast, oxalic acid precipitation also exhibits pH-dependent recovery but shows much lower selectivity, with higher pH promoting REE precipitation while simultaneously increasing co-precipitation of non-REE impurities. Both approaches demonstrate high efficiency, achieving comparable TREE recoveries through the sequential steps of mixing, stripping, and precipitation. However, transition-metal interference, particularly from Fe at elevated pH, affects the purity of the biosorption-derived stripped solution, even though similar amounts of REEs are recovered. This study demonstrates the potential of biosorption as a complementary approach to conventional methods, offering comparable REE recovery with lower reagent use and reduced secondary waste generation. Future work should include comprehensive environmental evaluations, such as life-cycle assessment and energy use analysis, to substantiate these benefits and guide scale-up for field applications.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 10","pages":"Pages 3021-3030"},"PeriodicalIF":9.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149072108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sm/Gd and Sm/Gd/Nd co-doping for tailoring magnetic, dielectric, and optical properties in CoFe2O4 nanomaterials","authors":"Mohammed Ahmed Wahba,&nbsp;Rabab K. Khaled","doi":"10.1016/j.jre.2025.11.009","DOIUrl":"10.1016/j.jre.2025.11.009","url":null,"abstract":"<div><div>CoFe₂O₄ (CFO) nanoparticles were synthesized and co-doped with Sm/Gd (SGCF) and Sm/Gd/Nd (SGNCF) using an assisted hydrothermal method to systematically examine the impact of rare earth substitution on their structural, magnetic, dielectric, and optical properties. X-ray diffraction (XRD) confirmed the formation of a single-phase spinel structure across all samples, with increased crystallite size observed upon doping. X-ray photoelectron spectroscopy (XPS) reveals Fe³⁺ and Co²⁺ oxidation states and noticeable shifts in Fe 2p and Co 2p binding energies, indicating changes in the electronic structure and local chemical environment. O 1s spectra further evidence doping-induced modulation of surface oxygen species and vacancies. Cation distribution analysis shows balanced Co occupancy in CFO, with SGCF favoring tetrahedral stabilization and SGNCF displaying a shift toward octahedral coordination. Magnetically, SGCF exhibits enhanced saturation magnetization (<em>M</em>_s = 65.92 emu/g) and coercivity (<em>H</em>_c = 915.80 Oe), compared to undoped CFO, while SGNCF shows a reduced saturation magnetization with magnetic moment of 2.51 <em>μ</em>_B. Dielectric measurements reveal decreased permittivity and AC conductivity at low frequencies in the doped samples, attributed to reduced interfacial polarization and grain boundary effects. Optical studies indicate a slight band gap narrowing from 1.36 eV (CFO) to 1.34 eV (SGCF) and 1.31 eV (SGNCF), suggesting quantum confinement and structural distortion. These findings demonstrate that rare earth co-doping effectively tunes the multifunctional properties of CFO, enhancing its suitability for spintronic, dielectric, and optoelectronic applications.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 10","pages":"Pages 2961-2972"},"PeriodicalIF":9.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149072181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}