Application Of Rare Earth Elements Research Articles

Cerium(III)-induced structural transformation of hexagonal birnessite: Effect of mineral phase transition on arsenite transport and valence changes

The widespread mining and application of rare earth elements (REEs) have led to their continuous accumulation in the environment, with increasing concentrations in soil. The interaction between the most abundant REEs, cerium (Ce), and the prevalent hexagonal birnessite (HB) in the environment is worth attention. HB is one of the most effective metal oxides for the oxidation of arsenite [As(III)] and subsequent adsorption, and thus for arsenic (As) immobilization. Therefore, in this study, we investigated the effect of the presence of Ce(III) ion on the HB formation process and the influence of generating minerals on the oxidation and removal of As(III). Research has found that the interfacial reactions of REEs in manganese (Mn) minerals not only affect their cycling but also alter the properties of the Mn minerals, thereby affecting the environmental fate of As. The results indicated that the presence of Ce ions affected the structure of HB during mineral synthesis and reduced the crystallinity of the conversion products. Their substitution for Mn(IV) in the lattice increased the specific surface area of minerals, reduced particle size, and produced more hydroxyl groups that were conducive to the immobilization of As(III). Meanwhile, Ce(III) was oxidized to Ce(IV) during the formation of Ce-bearing hexagonal birnessite (Ce-HB), and CeO2 nanoparticles were formed on the mineral surface and the removal rate of As(III) by Ce-HB was greatly improved. When the As concentration was lower than 6 mg·L−1, the removal effect of Ce-HB could reach the drinking water standard. However, the oxidation rate decreased due to the decrease in the proportion of Mn(IV). This study fundamentally reveals the behavior of HB coexisting with Ce in the migration and transformation of As(III) in the environment.

Optimizing the Recovery of Rare Earth Elements from Spent Fluorescent Lamps by Living Ulva sp.

Given the significant industrial applications of rare earth elements (REEs), supply chain constraints, and negative environmental impacts associated with their extraction, finding alternative sources has become a critical challenge. Previously, we highlighted the potential of living Ulva sp. in the removal and pre-concentration of Y from a solution obtained by sequential acid leaching of spent fluorescent lamps (SFLs). Here, we extended that study to other REEs extracted from SFLs and evaluated the effect of pH (4.5-9.0), light exposure (absence, natural and supplemented with artificial light), and Hg (presence and absence). The results showed small differences in the removal of Y (23-30%) and other REEs at the different pH values, opening the scope of the methodology. However, Ulva sp. relative growth rate (RGR) was negatively affected in the higher acidity condition, without any visible signs of decay. In the absence of light, the RGR also decreased, which was accompanied by a halving of the removal efficiency compared to that with artificial light supplementation (40% for Y). Although Hg had minimal influence on the removal and concentration of REEs by Ulva sp., its presence in the enriched biomass is undesirable. Therefore, this contaminant was selectively removed from the solution using Fe3O4@SiO2/SiDTC nanoparticles before contact with the macroalgae (70% removal in 30 min; 99% in 72 h). In addition to easy solubilization, macroalgae enriched with REEs have a simpler composition compared to SFLs. Calcination of the biomass allowed the REEs to be further concentrated, with concentrations (130 mg/g for Y) up to 240 times higher than in typical apatite ore. This highlights enriched biomass as a sustainable alternative to traditional mining for obtaining these critical raw materials.

Biostimulant Response of Foliar Application of Rare Earth Elements on Physiology, Growth, and Yield of Rice.

Rare earth elements (REEs) have been intentionally used in Chinese agriculture since the 1980s to improve crop yields. Around the world, REEs are also involuntarily applied to soils through phosphate fertilizers. These elements are known to alleviate damage in plants under abiotic stresses, yet there is no information on how these elements act in the physiology of plants. The REE mode of action falls within the scope of the hormesis effect, with low-dose stimulation and high-dose adverse reactions. This study aimed to verify how REEs affect rice plants' physiology to test the threshold dose at which REEs could act as biostimulants in these plants. In experiment 1, 0.411 kg ha-1 (foliar application) of a mixture of REE (containing 41.38% Ce, 23.95% La, 13.58% Pr, and 4.32% Nd) was applied, as well as two products containing 41.38% Ce and 23.95% La separately. The characteristics of chlorophyll a fluorescence, gas exchanges, SPAD index, and biomass (pot conditions) were evaluated. For experiment 2, increasing rates of the REE mix (0, 0.1, 0.225, 0.5, and 1 kg ha-1) (field conditions) were used to study their effect on rice grain yield and nutrient concentration of rice leaves. Adding REEs to plants increased biomass production (23% with Ce, 31% with La, and 63% with REE Mix application) due to improved photosynthetic rate (8% with Ce, 15% with La, and 27% with REE mix), favored by the higher electronic flow (photosynthetic electron transport chain) (increase of 17%) and by the higher Fv/Fm (increase of 14%) and quantum yield of photosystem II (increase of 20% with Ce and La, and 29% with REE Mix), as well as by increased stomatal conductance (increase of 36%) and SPAD index (increase of 10% with Ce, 12% with La, and 15% with REE mix). Moreover, adding REEs potentiated the photosynthetic process by increasing rice leaves' N, Mg, K, and Mn concentrations (24-46%). The dose for the higher rice grain yield (an increase of 113%) was estimated for the REE mix at 0.72 kg ha-1.

A distinctive rare earth element signature for pyrite oxidation and glacial weathering

The application of rare earth elements (REE) and neodymium (Nd) isotopes to authigenic Fe-(oxyhydr)oxide phases leached from marine sediments can be used for reconstructing past ocean circulation and chemical weathering patterns on nearby continental landmasses. To explore the behaviour of REE during chemical weathering in glacial environments, we analyzed the authigenic fraction of glacimarine sediments from the continental shelf off northern Svalbard (Arctic Ocean), where the evolution of ice sheet dynamics since the last deglaciation is well constrained. Our results show that leached authigenic fractions in Svalbard sediments exhibit shale-normalized REE patterns characterized by anomalously high mid-REE enrichment relative to both light- and heavy-REE, as expressed by concavity index values (CI > 2.5) that significantly depart from typical REE signatures for leached fractions in marine and river sediments worldwide. Using a compilation of literature data, we provide compelling evidence that the occurrence of pronounced mid-REE enrichment in authigenic fractions of Svalbard marine sediments links to terrestrial oxidation of pyrite following glacial weathering. While future investigation will be required to further understand the detailed mechanism accounting for the observed REE decoupling and its link to pyrite oxidation, we propose that preferential dissolution of mid-REE-enriched rock-bearing minerals such as apatite following glacial erosion, sulfide weathering and subsequent release of sulfuric acid could release a distinctive REE signature in glacial surface environments. Our findings suggest that the use of authigenic REE in the sedimentary record could provide a means for tracing glacial weathering and associated biogeochemical sulfur and iron cycling across geological times.

Associations between urinary rare Earth elements with renal function: Findings from a cross-sectional study in Guangxi, China

BackgroundWith increased applications of rare earth elements (REEs) across various industries, evaluating the relationship between REEs exposure and potential health effects has become a public concern. In vivo experiments have established that REEs impact renal function. However, relevant epidemiological evidence on this relationship remains scarce. The objective of this study is to examine the impact of exposure to REEs on renal function. MethodsIn this cross-sectional study, 1052 participants were recruited from Guangxi, China. We measured urinary concentrations of 12 REEs using an inductively coupled plasma-mass spectrometer (ICP-MS). Multiple linear regression models were developed to explore the relationship between a single REEs exposure and the estimated glomerular filtration rate (eGFR), a marker of renal function. Weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) were used to examine the combined effects of REE co-exposure on eGFR. ResultsIn the multiple linear regression analysis, increasing the concentrations of lanthanum (La, β: 8.22, 95% CI: 5.67–10.77), cerium (Ce, β:6.61, 95% CI: 3.80–9.43), praseodymium (Pr, β: 8.46, 95% CI: 5.85–11.07), neodymium (Nd, β:8.75, 95% CI: 6.10–11.41), and dysprosium (Dy, β:7.38, 95% CI: 4.85–9.91) significantly increased the eGFR. In the WQS regression model, the WQS index was significantly associated with eGFR (β: 4.03, 95% CI: 2.46–5.60), with Pr having the strongest correlation with eGFR. Similar results were obtained in the BKMR model. Additionally, interactions between Pr and La, and Pr and Nd were observed. ConclusionsCo-exposure to REEs is positively associated with elevated eGFR. Pr is likely to have the most significant influence on increased eGFRs and this might be exacerbated when interacting with La and Nd. Mixed exposure to low doses of REEs had a protective effect on renal function, which can provide some evidence for the exposure threshold of REEs in the environment. Trial registrationThe study has been approved by the Guangxi Medical University Medical Ethics Committee (#20170206–1), and all participants provided written informed consent.

Rare earth elements reveal the human health and environmental concerns in the largest tributary of the Mekong river, Northeastern Thailand

The widespread application of rare earth elements (REEs) in contemporary industries and agriculture, has caused emerging contaminant accumulation in aquatic environments. However, there is a limited scope of risk assessments, particularly in relation to human health associated with REEs. This study investigated the provenance, and contamination levels of REEs, further evaluating their environmental and human health risks in river sediments from an agricultural basin. The concentrations of REEs ranged from 30.5 to 347.7 mg/kg, with showing an upward trend from headwater to downstream. The positive matrix factorization (PMF) model identified natural and anthropogenic input, especially from agricultural activities, as the primary source of REEs in Mun River sediments. The contamination assessment by the geoaccumulation index (I-geo) and pollution load index (PLI) confirmed that almost individual REEs in the samples were slightly to moderately polluted. The potential ecological risk index (PERI) showed mild to moderate risks in Mun River sediment. Regular fertilization poses pollution and ecological risks to agricultural areas, manifesting as an enrichment of light REEs in river sediments. Nevertheless, Monte Carlo simulations estimated the average daily doses of total REEs from sediments to be 0.24 μg/kg/day for adults and 0.95 μg/kg/day for children, comfortably below established human health thresholds. However, the risk of REE exposure appears to be higher in children, and sensitivity analyses suggested that REE concentration contributed more to health risks, whether the adults or children. Thus, concerns regarding REE contamination and risks should be raised considering the wide distribution of agricultural regions, and further attention is warranted to assess the health risks associated with other routes of REE exposure.

Geochemical Study of Rare Earth Elements (REE) Distribution in Jeli, Kelantan, Malaysia: Correlation between Physical Appearance and Geochemical Composition

The application of rare earth elements (REE) in green technology has been rapidly expanded worldwide and demand for REE increased accordingly. Most REEs are mined from ion adsorption clay (IAC) which is claimed can be easily extracted and environmentally safe. REE was released within the soil profile and absorbed on the surfaces of the clay minerals. The aim of the study is to correlate the physical appearance and geochemical composition of REE in soil of Jeli, Kelantan. Petrography and geochemical methods were used to identify the characteristics of IAC samples that have been collected. According to the petrography, REE-bearing minerals such as monazite can be identified in sample JL17 which represents bedrock of granite found in Ayer Lanas. Elemental analysis and mineral identification in soil samples were determined using X-ray fluorescence (XRF) and X-ray diffraction (XRD) proving the samples are from clay association. Based on Inductively Coupled Plasma Mass Spectrometry (ICPMS) analysis, JL17, JL2 and JL19 contain high REE concentration ranged from 8000 to 200 ppm. Both samples have shared almost similar physical appearance in terms of reddish colour and fine-grain sized.

Application of rare earth elements as modifiers for Ni-rich cathode materials for Li-ion batteries: a mini review

This mini review article summarizes the recent progress in the modification of Ni-rich cathode materials for Li-ion batteries using rare earth elements. Although layered materials with high nickel content are the most promising cathodes due to their high capacity, the significant chemical, structural and thermal instability considerably hinders their practical application. Overcoming these limitations is possible through morphological or structural modifications based on doping and coating. Numerous reports regarding the use of various elements of the periodic table for this type of modification can be found in the literature. Surprisingly, rare earth elements are the least applied and described in the literature so far, even though they possess all the necessary features qualifying them as effective modifiers of layered cathode materials. This work summarizes the up-to-date publications regarding the application of rare earth elements as a highly prospective group of modifiers for layered Ni-rich cathode materials. These reports provide a better understanding of mechanisms of modification by rare earth elements and their beneficial effects on the electrochemical performance of the studied materials. New prospective strategies for layered cathode materials improvement have also been indicated.

Developing N,N,N’,N’-tetra (2-ethylhexyl) diglycolamide encapsulated polymeric beads as promising rare earth extracting agents

ABSTRACT The multi-faceted applications of rare earth elements (REE) in science and technology are not unknown. Scarcity in the primary sources of RE makes it necessary to explore different secondary sources available. Availability of REE in significant amount in spent NdFeB magnetic scrap makes the recycling of REE from this scrap, a lucrative option. In this work, synthetic solutions of 10 g/L (containing the rare earths Nd, Pr and Dy along with Fe) were equilibrated with the organic extractant N,N,N,’N’-tetra (2-ethylhexyl) diglycolamide (TEHDGA) encapsulated in polyethersulfone beads to study the extraction behavior of the REEs from nitric acid medium. Iron (Fe), the major component present in NdFeB scrap, poses the biggest challenge for rare earth extraction from the scraps. The TEHDGA impregnated polymeric beads were found to selectively extract the REEs, leaving Fe(III) in the feed solution. TEHDGA displayed higher selectivity towards the heavier rare earth Dy followed by Nd and Pr. The loading capacity of the beads was measured to be > 1700 ppm. The effect of different experimental parameters, such as contact time, solid-liquid ratio, TEHDGA concentration, feed acidity, were investigated. Contact time of 24 h, TEHDGA concentration of 0.75 M, solid-liquid ratio either 1:5 or 1:10 and feed acidity between 2 and 5 M have been found to suitable for quantitative extraction of REE particularly Dy(III). The recovery of the REEs from the loaded TEHDGA beads was > 90%. Furthermore, the experiment was carried out with higher quantity of beads and feed solution to study applicability of the same in bulk scale. A novel, easy and single-step separation of REE from Fe has been presented in this work.

Physicochemical Variation of Clay Minerals and Enrichment of Rare Earth Elements in Regolith-hosted Deposits: Exemplification from The Bankeng Deposit in South China

AbstractThe wide application of rare earth elements (REEs) in the development of a carbon–neutral society has urged resource exploration worldwide in recent years. Regolith-hosted REE deposits are a major source of global REE supply and are hosted mostly in clay minerals. Nonetheless, the ways in which changes in the physicochemical properties of clay minerals during weathering affect the concentrations of REEs in the regolith are not well known. In the current study, a world-class regolith-hosted REE deposit (Bankeng, South China) has been studied to illustrate further the effect of clay minerals on sorption and fractionation of REEs during weathering to form economic deposits. In the weathering profile, halloysite and illite are abundant in the saprolite due to weathering of feldspars and biotite from the bedrock. During weathering, halloysite and illite transform gradually to kaolinite and vermiculite. The large specific surface area, pore volume, and cation exchange capacity of the clay mineral assemblages are favorable to the sorption of REEs, probably because of the formation of vermiculite. The abundance of vermiculite could explain the enrichment of REEs in the upper part of the lower pedolith. For the saprolite-pedolith interface, halloysite is probably the main sorbent for the REEs, as indicated by the distinctive appearance of pore sizes of 2.4–2.8 nm characteristic of halloysite. The progressive transformation of halloysite to kaolinite reduces the pores and desorbs the REEs, causing REE depletion in the shallower soils. As a result, REEs were mobilized downward and re-sorbed in the lower pedolith-upper saprolite causing gradual enrichment and formation of these regolith-hosted deposits.

The advantage of praseodymium doped TiO2 composite as the support of Au catalysts for CO oxidation in CO2-rich atmosphere

In this study, based on the characteristic of lanthanide in oxygen storage capacity, a series of PraTibOx composite supports with different mole ratios of Pr to Ti and the corresponding Au catalysts were prepared - to investigate the oxidation of CO under CO2-rich atmosphere with lean oxygen content. A significant promotion in CO conversion rate over the catalyst with a molar ratio of Pr:Ti = 1:2 and a very high catalytic stability was also obtained. The addition of optimal Pr will make smaller gold particles, provide higher capacity in surface reactive oxygen releasing at low temperatures and weaken the deposition of carbonates in CO2-rich atmosphere. However, more Pr will strongly interact with gold, which leads to the majority of Au+ species in the catalysts and thus lower the catalytic activity. This study may provide a potential application of rare earth elements in sealed CO2-laser.

Cytotoxicity and hemolysis of rare earth ions and nanoscale/bulk oxides (La, Gd, and Yb): Interaction with lipid membranes and protein corona formation

The widespread application of rare earth elements (REEs) has raised concerns about their potential release into the environment and subsequent ingestion by humans. Therefore, it is essential to evaluate the cytotoxicity of REEs. Here, we investigated the interactions between three typical REEs (La, Gd, and Yb) ions as well as their nanometer/μm-sized oxides and red blood cells (RBCs), a plausible contact target for nanoparticles when they enter the bloodstream. Hemolysis of REEs at 50–2000 μmol L−1 was examined to simulate their cytotoxicity under medical or occupational exposure. We found that the hemolysis due to the exposure of REEs was highly dependent on their concentration, and the cytotoxicity followed the order of La3+ > Gd3+ > Yb3+. The cytotoxicity of REE ions (REIs) is higher than REE oxides (REOs), while nanometer-sized REO caused more hemolysis than that μm-sized REO. The production of reactive oxygen species (ROS), ROS quenching experiment, as well as the detection of lipid peroxidation, confirmed that REEs causes cell membrane rupture by ROS-related chemical oxidation. In addition, we found that the formation of a protein corona on REEs increased the steric repulsion between REEs and cell membranes, hence mitigating the cytotoxicity of REEs. The theoretical simulation indicated the favorable interaction of REEs with phospholipids and proteins. Therefore, our findings provide a mechanistic explanation for the cytotoxicity of REEs to RBCs once they have entered the blood circulation system of organisms.

Comparison of toxicity between lanthanum oxide nanoparticles and lanthanum chloride

Due to the wide application of rare earth elements, lanthanum (La) is gradually accumulated in our living environment. Lanthanum can enter the body through a variety of routes, which has a series of effects on various systems. As a consequence, the safety of lanthanum deserves our attention. This study aims to compare the toxicity of lanthanum oxide nanoparticles (La2O3 NPs) and lanthanum chloride (LaCl3) and enrich the toxicity evaluation of lanthanum. Therefore, a 30 d intragastal experiment was conducted. C57BL/6j mice were given by La2O3 NPs solution and LaCl3 solution respectively at doses of 0, 30, 60 and 120 mg/kg BW (lanthanum content). The results show that, compared with the control group, both La2O3 NPs and LaCl3 can reduce the body weight of female mice in the high-dose group, but for male mice, the high-dose La2O3 NPs solution can increase the body weight, while LaCl3 has the opposite effect. The coefficients of liver, kidney, heart, lung, uterine and ovaries increase first and then decrease with the exposure dose, but testes and epididymides coefficient keep increasing with the exposure of LaCl3 and La2O3 NPs. La2O3 NPs and LaCl3 can reduce the concentration of triglycerides (TG) and increase the level of low density lipoprotein (LDL), but the effect of La2O3 NPs is more obvious. La2O3 NPs and LaCl3 can reduce the concentration of malondialdehyde (MDA), increase the total antioxidant capacity (T–AOC) and enhance the activity of catalase (CAT), but LaCl3 has more obvious protective effects on oxidative stress. La2O3 NPs and LaCl3 have potential risks to liver, and the toxicity of La2O3 NPs might be higher than that of LaCl3.

Recent progress and prospects of rare earth elements for advanced aqueous zinc batteries

We analyze the unique roles played by rare earth elements from the three perspectives of cathode, anode and electrolyte. We summarize their potential applications and rational optimization strategies towards electrodes, separators and electrolytes.

Geochemistry of the Laptev and East Siberian seas sediments with emphasis on rare-earth elements: Application for sediment sources and paleoceanography

Deciphering the origin of sedimentary material in the Arctic can contribute to a deeper understanding of modern transport and sedimentation processes. Here, the application of rare earth elements (REEs) is particularly promising, as they can serve as indicators of sources as well as chemical and physical conditions and processes. This study aimed to determine the distribution of REE sources in the bottom sediments and the forms of their occurrence on the East Siberian Arctic Shelf. The concentrations and distributions of the REEs and major and trace metals, grain size, and mineral composition of 72 surficial sediment samples and two sediment cores that were collected from the Laptev and East Siberian seas were studied. Increasing REE content, the predominance of light REE, and close correlation with Zr, Nb, Y, Sc, and Ti were revealed in the Laptev and western East Siberian sea sediments in the zone of influence of the Lena River runoff. The source of the REEs was the eroded Yedoma complex along the coast. The REE content in the sub-colloidal fraction of the sediments was comparable to the REE concentration of the bulk bottom sediments and varied in the East Siberian Sea from 104 to 220 mg kg−1, with the maximum content around the submarine valley of the Indigirka River, in the Laptev Sea, ranging from 124 to 197 mg kg−1. The findings could be used to study ice dynamics and to conduct lithostratigraphic and paleoceanographical reconstructions of the Central Arctic.

Adsorption Equilibrium and Adsorption Kinetics of Rare Earth Elements in Coal Rocks

The adsorption pattern and mechanism of rare earth elements on coal reservoirs are still unclear, leading to difficulties in the application of rare earth elements in monitoring the fracturing effect of coal reservoirs. Through indoor adsorption experiments, the adsorption equilibrium and adsorption kinetics of rare earth elements Nd, Y and La on coal rocks were studied to simulate the adsorption of rare earth elements tracers on coal reservoirs and to explore the adsorption pattern of rare earth elements on coal rocks under different initial concentrations of rare earth elements, different adsorption times and different rare earth element types. The experimental results showed that the Langmuir isotherm equation fitted best, and the adsorption of rare earth elements on coal samples belonged to unimolecular layer adsorption, and the maximum adsorption of rare earth elements Nd, Y and La on coal samples at 25°C were 41.052 mg/kg, 34.301 mg/kg and 95.465 mg/kg, respectively. The proposed secondary kinetic equation can better describe the adsorption process of rare earth elements on coal rocks, indicating that chemisorption is the controlling step of the adsorption rate, with the coal samples showing the fastest adsorption rate for La elements and the slowest adsorption rate for Nd elements. The results of this study provide a reference for the application of rare earth elements in the evaluation of fracturing effects in coal reservoirs.

Toxic Effects of Two Representative Rare Earth Elements (La and Gd) on Danio rerio Based on Transcriptome Analysis.

The expanding applications of rare earth elements (REEs) in various fields have raised concerns about their biosafety. However, previous studies are insufficient to elucidate their toxic effects and mechanisms of action and whether there are uniform or predictable toxicity patterns among REEs. Herein, we investigated the toxic effects of two representative REEs (lanthanum (La) and gadolinium (Gd)) on zebrafish (Danio rerio) through toxicity experiments and transcriptome analysis. The results of the toxicity experiments showed that the two REEs have similar lethality, with half-lethal concentrations (LC50) at micromolar levels and mixed toxicity showing additive effects. Differential expression gene screening and functional group enrichment analysis showed that La and Gd might affect the growth and development of Danio rerio by interfering with some biological molecules. The two REEs showed significant effects on the metabolic pathways of exogenous or endogenous substances, including glutathione sulfotransferase and acetaldehyde dehydrogenase. Moreover, some basic biological processes, such as DNA replication, the insulin signaling pathway, and the p53 signaling pathway, were significantly enriched. Overall, the toxicity patterns of La and Gd may affect some biological processes with different intensities; however, there are many similarities in their toxicity mechanisms and modes of action. The concentrations investigated in this study were comparable to those of REE residues at highly contaminated sites, thus mimicking the ecotoxicological effects at environmentally relevant concentrations.

Comparative study of two methods for rare earth elements analysis in human urine samples using inductively coupled plasma-mass spectrometry

The application of rare earth elements (REEs) in several areas, including high-tech technology, agriculture, medicine, and fuels, has made them an essential component of our everyday life. This extensive use of REEs in several technologies is expected to potentially impact human health. Even if several studies investigated the levels of REEs in human matrices, until now no standard method has been established for analyzing these elements in human matrices. The sample analysis should be of high quality, and the methods should be validated properly to ensure the quality of the procedure and traceability of the analytical data. In this research, we compared the validation and effectiveness of two different methods of sample preparation for human urine samples: a simple dilution of the sample (DIL) was compared with microwave assisted-acid decomposition (MIN) for tracing REE levels in human urine samples. The analysis was carried out by inductively coupled plasma mass spectrometry (ICP-MS). The working conditions have been set in high-sensitivity mode. Accuracy of the proposed method was evaluated by spiking the sample matrix with known concentrations of analyte standards. Both methods showed adequate precision of repeatability and intra-laboratory reproducibility, with the DIL method showing better precision of both repeatability and reproducibility than the MIN method. The CVr% values of repeatability range from 1.5 to 12% for the DIL and from 8.4 to 16% for the MIN method. The CVr% values of reproducibility range from 6.2–23% for the DIL and from 8.6 to 24% for the MIN method. REE recoveries for both methods were very close to 100%. Both methods proved to be effective for the determination of REE levels in human urine matrices.

Applications of rare earth elements in cancer: Evidence mapping and scientometric analysis.

Cancer is one of the most important public health issues worldwide. Radiation therapy (XRT), chemotherapy, and targeted therapy are some of the main types of cancer therapy. Metals are used extensively in cancer diagnosis and therapy, and rare earth elements occupy an important niche in these areas. In recent years, an increasing number of studies have focused on the application of lanthanides in cancer diagnosis and therapy. However, no research has analyzed the current status and future trends of lanthanides in treating cancer. We downloaded data from publications from the Web of Science Core Collection. We used VOSviewer 1.16.16 software and Excel 2016 to analyze literature information, including publication years, journals, countries, institutes, authors, keywords, and co-cited references. A total of 7,849 publications were identified. The first study on the association of rare earth elements with cancer was published in 1945. However, before 1979, the number of publications per year was no more than 10. After 1980, the number of yearly publications increased. The United States was the most productive country (2,726, 34.73%), and the institution with the most frequent contributions was the Chinese Academy of Sciences (211, 2.69%). We observed close collaboration between countries and between institutes. The 7,839 publications were published in 1,579 journals, and Radiology was both the most productive journal (183, 2.33%) and cited journal (5,863 citations). A total of 33,987 authors investigated rare earth elements and cancer. Only 0.45% of the authors published more than 10 publications, and 79.07% of the authors published only one publication. Of the top 10 high-yield authors, seven were from developed countries and three were from China. However, among the top 10 co-cited authors, there was only one high-yield author. The main research topics in the application of lanthanide complex-doped nanomaterials in the diagnosis and treatment of cancer include magnetic resonance imaging contrast agents, photodynamic therapy, anticancer drug delivery, the efficacy and safety of yttrium-90 radioimmunotherapy and chemoembolization for the treatment of HCC, gadolinium magnetic resonance imaging (MRI) contrast agent for cancer diagnosis, and cerium oxide nanoparticles. In recent years, especially since 2016, the research frontiers are emerging in cerium oxide nanoparticles and photodynamic therapy. Studies related to the application of rare earth elements and cancer have significantly increased over the past 20 years. The United States contributed the most articles in the field, followed by China and Germany, and cooperation among countries was frequent. The Chinese Academy of Sciencess, Northwestern University, and Stanford University were the three most productive institutions, and cooperation among institutions was frequent. Many high-quality journals have published relevant research, but there are few highly productive journals.

Utilization of sludge-based alginate beads for the application of rare earth elements (REEs) recovery from wastewater: A waste to resource approach

The main purposes of this research work were to realize the potential of sludge valorization by converting the sludge into adsorbents and to investigate the performance of sludge-based adsorbents for rare earth elements (REEs) recovery from dilute aqueous solutions. Hydrochloric acid and Fenton reagents were employed as pretreatment procedures to enhance the surface area and adsorption yield. Following this, sludge-based alginate beads were prepared by using HCl treated (HT) and Fenton treated (FT) sludge materials. The chemical composition and surface chemistry of sludge-based adsorbent beads were thoroughly analyzed by state-of-the-art analytical techniques, such as Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) analysis. The prepared beads were then investigated for the recovery of REEs. The batch adsorption studies revealed that the FT sludge beads performed better in comparison to the HT sludge beads. Among REEs, the HT- and FT-sludge beads demonstrated higher affinity towards Sm 3+ ions, displaying the maximum adsorption capacities of 2.83 mg/g and 4.16 mg/g, respectively, in a multi-component system (C o = 25 ppm of each REE; pH = 5, t = 24 h and dosage = 5 g/L). In conclusion, the results from this work showed that the prepared sludge-based alginate beads can be used for REEs recovery from diluted waste streams and the tested sludge treatment options were also found effective in converting the waste to resource i.e., sludge to adsorbent for REEs recovery. • Hydrochloric acid and Fenton reagents were used in the pre-treatment of sludge. • Treated sludge was transformed into beads to recover REEs from wastewater. • Sorption capacity of beads were investigated at pH (2–5) and pH 5 became optimal point. • Max. adsorption capacities of Sm 3+ , 2.83 mg/g (HCl treated) and 4.16 mg/g (Fenton treated).