Search Results (10)

Waste electronic components are valuable secondary resources containing various metals. Analyzing their elemental distribution is crucial for developing recycling methods. Micro- X-ray fluorescence (μ-XRF) is commonly used for this purpose, but traditional polychromatic X-ray excitation creates high background scattering. This masks trace element signals, impairing detection limits and accurate identification of minor valuable or hazardous elements. To address this, this study developed a monochromatic μ-XRF spectrometer using a low-power molybdenum-target X-ray tube. The system integrates polycapillary lenses for X-ray regulation and a flat crystal for monochromatization, producing a micron-sized monochromatic X-ray spot with high power density. This design eliminates scattered background from the primary continuous spectrum and enhances excitation efficiency by concentrating photon flux, enabling high-brightness monochromatic beams even at low tube power. The spectrometer was validated by analyzing a waste printed circuit board. High-resolution elemental mapping successfully revealed clear distribution patterns of major elements like copper, nickel, and iron, consistent with their physical structures. These images allowed intuitive differentiation of compositional differences across functional regions. This technique effectively overcomes the background interference caused by polychromatic excitation and is expected to further enhance the quality and reliability of elemental distribution imaging. It provides a powerful tool for formulating precise, scientific recycling strategies for waste electronics. Full article

The longevity, site fidelity, and trophic position of freshwater turtles have led to their increasing recognition as useful bioindicators of environmental contamination. Mauremys leprosa (n = 25) shells from a Northern African wetland system were examined for trace element concentrations in order to assess shell composition as a non-invasive biomonitoring method. Micro x-ray fluorescence (μXRF) method was used to measure the shell concentrations of 17 elements, including Ca, P, Fe, Zn, Mn, Sr, Pb, Sb, and Al. As would be expected from the structural composition of bony tissues, calcium and phosphorus were the predominant constituents. In addition to bulk concentrations, micro-XRF elemental mapping revealed heterogeneous spatial distributions of essential and toxic elements within the shells, providing visual evidence of bioaccumulation patterns and supporting the use of shells as non-invasive bioindicators. There were statistically significant sex-related differences in the levels of trace elements, with males exhibiting higher concentrations of Mg, Mn, Sb, Pb, and Al (p < 0.05). Spearman correlations revealed strong associations between certain shell elements (e.g., Fe, Mn, Ti, Zn) and morphometric parameters. Comparisons with environmental samples (water and sediment) showed moderate to strong correlations, particularly with sediment metal concentrations, supporting the utility of shell chemistry as an integrative exposure matrix. Nonetheless, there were significant percentages of censored or missing values for certain metals (Cu, Ni, and As). This study emphasizes how viable turtle shells are as non-lethal markers of bioaccumulation and stresses how crucial it is to take environmental matrices, element-specific variability, and sex into account when assessing contamination. Longitudinal monitoring, physiological biomarkers, and isotopic analysis should all be used in future studies to bolster the causal relationships between environmental exposure and turtle health. Full article

While existing studies on Guatemalan jadeite have predominantly focused on green varieties, the coloration mechanisms and origin of its blue counterparts remain poorly understood. Therefore, the present study provides the first comprehensive investigation of the Guatemalan blue jadeite using an integrated analytical approach, which combines Raman spectroscopy, micro X-ray fluorescence (µ-XRF), electron microprobe analysis (EMPA), X-ray diffraction (XRD), UV-Vis spectroscopy, and Cathodoluminescence (CL) imaging on seven representative samples. The results demonstrate that these jadeites consist of two distinct phases: a primary jadeite phase (NaAlSi₂O₆) and a secondary omphacite that form by metasomatic alteration by Mg-Ca-Fe-rich fluids. Spectroscopic analysis reveals that the blue coloration is primarily controlled by Fe³⁺ electronic transitions (with characteristic absorption at 381 nm and 437 nm) coupled with Fe²⁺-Ti⁴⁺ intervalence charge transfer, supported by μ-XRF mapping showing strong Fe-Ti spatial correlation with color intensity. CL imaging documents a multi-stage formation history involving initial high-pressure crystallization (Jd-I) followed by fluid-assisted recrystallization forming Jd-II and omphacite. The detection of CH₄, CO and H₂O in the fluid inclusions by Raman spectroscopy indicates formation in a serpentinization-related reducing environment, while distinct CL zoning patterns confirm a fluid-directed crystallization (P-type) origin. These findings not only clarify the chromogenic processes and petrogenesis of Guatemalan blue jadeite but also establish key diagnostic criteria for its identification, advancing our understanding of fluid-derived jadeite formation in subduction zone environments. Full article

Hydrothermal alteration provides critical information for both the exploration and scientific research of hydrothermal uranium deposits. The Xiangshan uranium ore field, the largest volcanic-hosted uranium deposit in China, is characterized by different alterations, including hematitization, illitization, sericitization, chloritization, carbonation and silicification. However, the mineralogical and geochemical characteristics of hydrothermal alterations and their relationships with uranium mineralization remain unclear. In this study, we conducted detailed petrography, TIMA mapping, μ-XRF analyses, mass balance calculations and thermodynamic modeling on the hematitized and illitized porphyritic lava from the Zoujiashan deposit in the Xiangshan ore field. During hematitization, hematite and albite are produced, while quartz, K-feldspar, chlorite, sericite and biotite are consumed, consistent with the increase in Na₂O, Al₂O₃, Fe₂O₃-T, U, As, Pb, Cu, Sc, V, Zr, Y, Hf and Th and the loss of K₂O, MgO, Li, Zn, Ni and Ba. The production of hydrothermal hematite, illite and sericite indicates that the ore fluids are acidic and oxidized. Such physiochemical conditions are favorable for uranium transport as UO₂Cl₂(aq), UO₂SO₄(aq) and UO₂OH⁺. Geological processes such as fluid–rock interactions, fluid mixing and fluid boiling could cause fO₂(g) decrease, pH increase and temperature decrease and therefore result in the decrease in uranium solubility and mineralization. Full article

Scanning micrο X-ray fluorescence (μ-XRF) and multispectral imaging (MSI) were applied to study philately stamps, selected for their small size and intricate structures. The μ-XRF measurements were accomplished using the M6 Jetstream Bruker scanner under optimized conditions for spatial resolution, while the MSI measurements were performed employing the XpeCAM-X02 camera. The datasets were acquired asynchronously. Elemental distribution maps can be extracted from the μ-XRF dataset, while chemical distribution maps can be obtained from the analysis of the multispectral dataset. The objective of the present work is the fusion of the datasets from the two spectral imaging modalities. An algorithmic co-registration of the two datasets is applied as a first step, aiming to align the multispectral and μ-XRF images and to adapt to the pixel sizes, as small as a few tens of micrometers. The dataset fusion is accomplished by applying k-means clustering of the multispectral dataset, attributing a representative spectrum to each pixel, and defining the multispectral clusters. Subsequently, the μ-XRF dataset within a specific multispectral cluster is analyzed by evaluating the mean XRF spectrum and performing k-means sub-clustering of the μ-XRF dataset, allowing the differentiation of areas with variable elemental composition within the multispectral cluster. The data fusion approach proves its validity and strength in the context of philately stamps. We demonstrate that the fusion of two spectral imaging modalities enhances their analytical capabilities significantly. The spectral analysis of pixels within clusters can provide more information than analyzing the same pixels as part of the entire dataset. Full article

Historical coal mining practices have caused various soil and water hazards, particularly through the dumping of mine waste. The primary environmental risk associated with this waste is the leaching of toxic metals from dumps of spoil or refuse into the subsurface soil or into nearby water resources. The extent of metal release is controlled via the oxidative dissolution of pyrite and potential re-sequestration through secondary Fe oxides. The characterization of the dominant Fe-bearing phase and the distribution of trace metals associated with these phases was determined via electron microscopy, synchrotron-based X-ray micro-fluorescence (μ-XRF) element and redox mapping from shallow mine soils from an impacted watershed in Appalachian Ohio. The dominant Fe-bearing phases were: (1) unweathered to partially weathered pyrite; (2) pseudomorphic replacement of pyrite with Fe(III) oxides; (3) fine-grained Fe oxide surface coatings; and (4) discrete Fe(III) oxide grains. Thicker secondary coatings and larger particles were sulfate rich, whereas smaller grains and thinner coatings were sulfate poor. The discrete Fe oxide grains exhibited the highest concentrations of Cr, Mn, Ni, and Cu, and sub-grain-scale concentration trends (Mn > Cr > Ni > Cu) were consistent with bulk soil properties. Predicting future metal transport requires an understanding of metal speciation and distribution from the sub-grain scale to the pedon scale. Full article

In this study, growth and ionomic responses of three duckweed species were analyzed, namely Lemna minor, Landoltia punctata, and Spirodela polyrhiza, were exposed for short-term periods to hexavalent chromium or nickel under laboratory conditions. It was found that different duckweed species had distinct ionomic patterns that can change considerably due to metal treatments. The results also show that, because of the stress-induced increase in leaf mass-to-area ratio, the studied species showed different order of metal uptake efficiency if plant area was used as unit of reference instead of the traditional dry weight-based approach. Furthermore, this study revealed that μXRF is applicable in mapping elemental distributions in duckweed fronds. By using this method, we found that within-frond and within-colony compartmentation of metallic ions were strongly metal- and in part species-specific. Analysis of duckweed ionomics is a valuable approach in exploring factors that affect bioaccumulation of trace pollutants by these plants. Apart from remediating industrial effluents, this aspect will gain relevance in food and feed safety when duckweed biomass is produced for nutritional purposes. Full article

Quantitative characterisation through mineral liberation analysis is required for effective minerals processing in areas such as mineral deposits, tailings and reservoirs in industries for resources, environment and materials science. Current practices in mineral liberation analysis are based on 2D representations, leading to systematic errors in the extrapolation to 3D volumetric properties. The rapid development of X-ray microcomputed tomography (μCT) opens new opportunities for 3D analysis of features such as particle- and grain-size characterisation, determination of particle densities and shape factors, estimation of mineral associations, and liberation and locking. To date, no simple non-destructive method exists for 3D mineral liberation analysis. We present a new development based on combining μCT with micro-X-ray fluorescence (μXRF) using deep learning. We demonstrate successful semi-automated multimodal analysis of a crystalline magmatic rock by obtaining 2D μXRF mineral maps from the top and bottom of the cylindrical core and propagating that information through the 3D μCT volume with deep learning segmentation. The deep learning model was able to segment the core to obtain reasonable mineral attributes. Additionally, the model overcame the challenge of differentiating minerals with similar densities in μCT, which would not be possible with conventional segmentation methods. The approach is universal and can be extended to any multimodal and multi-instrument analysis for further refinement. We conclude that the combination of μCT and μXRF can provide a new opportunity for robust 3D mineral liberation analysis in both field and laboratory applications. Full article

The main goal of this study was to identify potential chemical elements present in three types of polymetallic mine waste, stored in the old mine site of São Domingos, located in the Iberian Pyrite Belt, Alentejo, Southern Region of Portugal. This study involves the characterization of potential resources in those mine residues, bearing in mind that its reprocessing can facilitate the environmental remediation and rehabilitation activities which are underway at the site. X-ray Fluorescence (XRF) and micro (μ)-XRF 2D mapping surveys were performed. Univariate and multivariate data analysis reveal that differences in compositions are mainly related with element concentration per type of waste. Image processing and clustering analysis allowed the recognition of distinct elemental spatial distribution patterns. Some of these residues, although classified as archeological-industrial heritage materials may present toxicity to the ecological environment and to human health. This fact enhances, therefore, geoethical doubts regarding its remining and exploitability. In this context, a multi-criteria decision analysis considering two geoethical alternatives was performed. Full article

This research concerns the application of micro X-ray fluorescence (µXRF) mapping to the investigation of a group of selected metal objects from the archaeological site of Ferento, a Roman and then medieval town in Central Italy. Specifically, attention was focused on two test pits, named IV and V, in which metal objects were found, mainly pertaining to the medieval period and never investigated before the present work from a compositional point of view. The potentiality of µXRF mapping was tested through a Bruker Tornado M4 equipped with an Rh tube, operating at 50 kV, 500 μA, and spot 25 μm obtained with polycapillary optics. Principal component analysis (PCA) and multivariate curve resolution (MCR) were used for processing the X-ray fluorescence spectra. The results showed that the investigated items are characterized by different compositions in terms of chemical elements. Three little wheels are made of lead, while the fibulae are made of copper-based alloys with varying amounts of tin, zinc, and lead. Only one ring is iron-based, and the other objects, namely a spatula and an applique, are also made of copper-based alloys, but with different relative amounts of the main elements. In two objects, traces of gold were found, suggesting the precious character of these pieces. MCR analysis was demonstrated to be particularly useful to confirm the presence of trace elements, such as gold, as it could differentiate the signals related to minor elements from those due to major chemical elements. Full article