Search Results (480)

Significant mineral phase partitioning of various elements is widely observed in marine sediments. Distinct elemental responses to grain-size sorting hinder accurate conversion of XRF scanning counts to elemental concentrations, yet this geological mechanism lacks quantitative constraints. We analyzed 214 paired sediment samples from four cores collected in the Western and Central Pacific, employing an ensemble machine learning framework integrated with multi-stage linear calibration baselines to quantify grain-size impacts on predictions of ten major oxides. (1) Grain-size correction shows element-selective effects: SiO₂ shows the highest sensitivity, with its R² declining from 0.669 to 0.524 after grain variables are excluded; sensitivity gradually weakens for P₂O₅ and MgO, while Al₂O₃ and K₂O remain largely unaffected. (2) Such discrepancies may be related to differences in mineral carriers: silicon may occur in both coarse quartz debris and fine aluminosilicate particles, whereas Al₂O₃ and K₂O show relatively stable predictive relationships. (3) Due to the combined influence of biogenic, authigenic, and terrigenous carbonates, the CaO prediction accuracy varies considerably across core datasets. Excluding grain-size data resulted in a slight improvement in accuracy, as the coupling relationships between calcium content and grain size across different cores exhibit opposing trends that partially cancel out. These results indicate that provenance differences limit the transferability of CaO correction models across cores. Through feature ablation tests, this study quantitatively demonstrates the element-specific patterns of grain-size correction and their possible relationships with mineral carriers, offering practical guidance for calibration protocols used in reconstructing and interpreting paleoceanographic XRF geochemical profiles. The proposed workflow is therefore limited to down-core interpolation within calibrated depth intervals and is not intended for extrapolation beyond the training range. Full article

This study reports the sonocatalytic degradation of malachite green (MG) in media using synthesized Co₃O₄ nanoparticles and a CTAB-modified zeolite supported Co₃O₄ hybrid nanocatalyst (M-ZLT@Co₃O₄). The catalysts were characterized by XRD, FT-IR, SEM-EDX, TEM, XRF, N₂ adsorption–desorption, BET, and BJH analyses, verifying crystalline Co₃O₄ formation, successful immobilization on the modified zeolite support, porous architecture, morphology and elemental distribution. Under optimized conditions of 1 g L⁻¹ catalyst dosage, 20 mg L⁻¹ MG concentration, natural pH, and 300 W L⁻¹ ultrasonic power, M-ZLT@Co₃O₄ achieved 99.31% ± 0.45% degradation within 120 min. Decreasing the MG concentration to 5 mg L⁻¹ increased the efficiency to 99.96% ± 0.64%, confirming high activity at low pollutant loading. The degradation followed pseudo-first-order kinetics, with k_app values of 0.0042–0.0595 min⁻¹ depending on catalyst dosage, 0.0046–0.0667 min⁻¹ for initial MG concentration, and 0.0117–0.0620 min⁻¹ under pH conditions. Water matrix inhibition followed distilled water (99.31%) > tap water (96.08%) > river water (88.84%) > lake water (86.90%), whereas higher ultrasonic power increased degradation from 91.98% at 200 W L⁻¹ to 99.90% at 500 W L⁻¹. Dye degradation followed MG (99.31%) > CR (95.78%) > BY2 (92.15%) > MV (90.24%) > AO7 (85.62%) > RB19 (82.49%). Comparative tests demonstrated performance for US/M-ZLT@Co₃O₄ (99.31%) compared with US/Co₃O₄ nanoparticles (78.48%), US/ZLT (72.86%), and US/MG alone (35.71%). The best activity was obtained at 0.8–2 g L⁻¹ catalyst dosage and 5–20 mg L⁻¹ MG concentration, while reusability tests showed a decrease from 99.31% to 78.82% after six cycles, indicating promising stability. Full article

The study of heterogeneous exceptional objects preserved in different places implies the use of various instruments. Here, we compare the manufacturing techniques of two rare enameled glasses (a box and a vase) made for the Kangxi Emperor (r. 1661–1722) using XRF analyses performed in the laboratory for one object and with a mobile spectrometer for the other. The enamels are identified and compared based on the characteristic signals of different chemical elements, with or without multivariate analysis. Although the bodies have similar compositions (but differ in trace elements) and are opacified with calcium arsenate, large differences are observed for certain enamels: the red of the box is obtained using the traditional Chinese method based on copper nanoparticles, while the brown and purple to pink of the vase use gold nanoparticles, a recipe imported from Europe. The white highlights of the box are opacified with tin. Cobalt is rich in arsenic and contains bismuth and nickel, consistent with European importation as reported in historical sources. Naples yellow is used in both objects. A comparison of the distinctive features of these objects with those of painted enameled imperial porcelain and cloisonné enamelware further highlights the technological exchanges and material choices involved in the production of imperial decorative objects, as well as the very innovative ‘research’ conducted at the imperial glass workshop. Full article

The generation of agro-industrial waste necessitates the search for viable, sustainable alternatives for its utilization; therefore, Hydrothermal Carbonization (HTC) is proposed as a means to transform waste into carbonaceous products that can improve soil quality. To this end, conditions in the HTC process were evaluated for the production of hydrochar from tequila vinasse and Agave tequilana Weber leaves. Different reaction times (8, 12, and 16 h) and catalyst concentrations (0%, 5%, and 10%) of citric acid were evaluated at 200 °C, using fresh agave leaves and raw vinasse. The hydrochars were characterized using various instrumental analyses (XPS, FTIR, SEM-EDS, and XRF) to determine their structure, functional groups, and elemental composition. The highest yield was obtained at 8 h without a catalyst (44.6%), decreasing with increasing process time. The vinasse served effectively as an aqueous medium and natural catalyst, with its acidic pH (3.8), thereby eliminating the need for water and acid addition. With longer processing times, microspheres form within the hydrochar structure due to carbohydrate degradation. The hydrochar produced without a catalyst and with a shorter reaction time exhibited functional groups (carboxyl and hydroxyl) that enhance Cation Exchange Capacity (CEC), thereby increasing the contact surface area. Under the evaluated conditions, the HTC process is suitable for producing hydrochar from agave leaves and vinasse. Full article

Total organic carbon (TOC) is a key parameter for source-rock evaluation, but laboratory measurements are sparse and do not resolve continuous vertical variation. Conventional well logs provide continuous physical responses, whereas X-ray fluorescence (XRF) data add geochemical information. We evaluated the incremental value of combining these data sources using 58 depth-matched samples from the Yiwan-1 well in the Wangjiawan area, South China. Four well-log variables and six XRF variables selected within each training fold were evaluated with nine models under repeated 5-fold cross-validation (20 repeats). The fused SVR model performed best (RMSE = 0.789 ± 0.267; R = 0.912 ± 0.081). At the repetition level, the absolute RMSE reduction relative to logs alone was 0.430 (95% CI: 0.386–0.478), equivalent to 35.3% (Holm-adjusted p = 1.34 × 10⁻⁵). A 500-run permutation test that shuffled complete XRF sample rows gave an empirical p-value of 0.002. In a separate contiguous depth-block analysis with a 0.16 m exclusion buffer, the SVR RMSE decreased from 2.566 to 1.837, corresponding to an improvement of 28.4%, although the benefit was not retained by every linear model. Mo, V, Cr, Cd and Zn were selected in all Pearson-selection folds and had positive mean held-out permutation importance. The results support a complementary contribution from XRF data within this well while also showing that estimated accuracy depends on the validation design. Full article

Waste from the aggregate processing industry has the potential to be used for value-added products. Its plastic properties and sinterability allow for the production of lightweight aggregates. This process can yield materials with high open porosity at various scales. This article presents the possibilities of obtaining lightweight aggregates from clay–silt fractions obtained by washing crushed dolomite aggregates. Aggregate formation was achieved using selected mechanical processing methods, such as dynamic granulation, sedimentation, crushing, and classification. Biomass was added to increase the aggregate’s porosity. The following instrumental techniques were used to assess the aggregate’s parameters: X-ray fluorescence (XRF) to obtain detailed information on the oxide composition of the tested raw materials; high-temperature microscopy (HSM) to determine the specific sintering temperature; and pH and conductivity meters to examine filtration solutions in direct contact with the aggregate. A key issue was to examine the microstructure of the produced aggregates after firing using scanning electron microscopy (SEM), Brunauer–Emmett–Teller method for measuring material surface area (BET), and X-ray diffraction (XRD) technique. The obtained results will allow for further research into developing a concept for the production of lightweight alkaline aggregates. The aggregates produced exhibit high water absorption (approximately 50%), a low bulk density of 0.82 g/cm³, and meso- (approximately 30–100 µm) and bioporosity (approximately 100–500 µm), which is beneficial for the proper development of plant roots and the absorption and release of water. This research contributes to the identification of resources that can be transformed into lightweight aggregates for urban greening, which is consistent with circular economy strategies and environmental protection. The specific mechanisms through which this research supports sustainable development are the reduction in landfill sites and the protection of natural resources. Furthermore, the aggregates produced can form part of blue-green urban infrastructure, which aims to manage rainwater and reduce the urban heat island effect. Full article

The tropical fruits velvet tamarind, baobab, and African locust beans are used as foods and in beverages for medicinal purposes. They are important sources of nutrients and bioactive compounds. This research focused on the bioactive composition in the fruit pulps and seeds of these African plant species. Spectrophotometric analysis of the total phenolic and flavonoid contents, the antioxidant capacity (DPPH, FRAP, and ABTS assays), the quantification and profile of phenolic compounds, hydrosoluble vitamins B and C (HPLC), and fatty acids (GC-FID), and the toxicological analysis of amygdalin (HPLC) and elements (XRF) were assessed. The fruit velvet tamarind exhibited the highest TPC, TFC, and antioxidant capacity, with seed content higher than pulp, primarily due to naringin (54.45 mg/100 g). Baobab presented the second highest TPC and TFC content and antioxidant capacity, with pulp being higher than seed, mainly due to vitamin C (79.97 mg/100 g) and rutin (47.92 mg/100 g). Several bioactive compounds were quantified, such as vitamin C, various hydroxycinnamic acids (caffeic, p-coumaric, chlorogenic, ferulic), hydroxybenzoic acids (gallic, vanillic), and polyphenols (quercetin, catechin, epicatechin, rutin, naringin, procyanidin, kaempferol), as well as fatty acids from the ω-3 and ω-6 series. Amygdalin was not detected in any seeds, and Cd content was higher than 0.05 mg/kg of dry weight. Full article

Recent attempts at petroglyph dating have focused on measuring the manganese accumulation in the rock varnish coating that develops in a motif groove after it was engraved, under the assumption that this amount is systematically related to age. These efforts reflect the basic need for chronological control for both heritage management and research purposes. Despite the wide availability of portable X-ray fluorescence devices and their ability to take non-destructive field measurements of manganese, these applications have not examined the nature or location of the manganese being analyzed. We employ a mixture of electron microscope methods on samples of petroglyphs obtained from prior investigations of petroglyphs to assess this problem. Results reveal that significant amounts of manganese associated with petroglyphs derive from sources other than the post-engraving rock varnish coating, including the weathering rinds underlying varnish, isolated patches of inherited varnish that were not completely removed during petroglyph engraving, and silica glazes. Significant amounts of manganese also may be removed by microcolonial fungi that, in our samples, dissolve between 22 and 60% of a rock varnish coating. Until the manganese accumulation petroglyph dating approach is able to distinguish manganese subtractions from acid-producing fungi and additions from non-varnish sources from varnish sources, it cannot provide reliable age estimates. Full article

An accurate prediction of gypsum-salt cap rocks is crucial for safe drilling and efficient development of subsalt hydrocarbons in the Tarim Basin. However, due to the complex lithological assemblages within the Middle Cambrian sequences, the P-impedance of gypsum severely overlaps with that of the background carbonate rocks, making conventional seismic prediction based on a single impedance threshold inadequate. To address this issue, this paper proposes a multi-parameter coupling while-drilling prediction method that integrates seismic data, drilling parameters and geochemical logging. First, pre-stack P-impedance inversion is performed on amplitude-preserved seismic data to macroscopically delineate the depth interval of gypsum-salt development. Second, a weighted synthetic change-rate model incorporating drilling time (DT), weight on bit (WOB), and outlet conductivity is constructed to dynamically calibrate the top interface of the gypsum-salt layer while drilling. Finally, within the constrained depth interval, X-ray fluorescence (XRF) elemental inversion of cuttings is used to quantitatively calculate the contents of clay, dolomite, gypsum and calcite, achieving fine-scale lithofacies identification at the sublayer level. An empirical application to Well XSC1 in the Keping fault-uplift, Tarim Basin, demonstrates that compared with the conventional single P-impedance threshold method, the proposed approach effectively distinguishes gypsum, salt and carbonate wall rocks, and significantly reduces the prediction errors of individual salt beds and gypsum sublayers. Specifically, the mean absolute error (MAE) of total gypsum-salt content decreases from 24.56% to 13.73% (a reduction of 44.1%), the bias drops from 2.45% to 0.31%, and the root mean square error (RMSE) decreases from 33.63% to 21.55%. At a 1% content threshold, the F1 score for gypsum-salt identification increases from 0.63 to 0.82; the absolute depth error of the top and bottom interfaces is reduced by approximately 70%, and the relative thickness error shrinks from $\pm$40% to within $\pm$10%. Transferability of this multi-parameter coupling strategy to other salt-bearing basins in central-western China remains unvalidated and requires future validation and testing. Full article

The global water crisis represents one of humanity’s most pressing challenges, with over 2 billion people lacking access to safely managed drinking water. This study presents the implementation and evaluation of an innovative air-conditioning condensate recovery system at Building F of the Faculty of Electrical and Electronic Engineering (FIEE), Universidad Veracruzana, Mexico. The system integrates twenty-six 24,000 BTU air-conditioning units across twelve classrooms and two laboratories, recovering approximately 520 L of condensate water daily. An initial physicochemical characterization of the recovered condensate was conducted through pH, electrical conductivity (EC), and total dissolved solids (TDS) measurements. In addition, the dried residue obtained after evaporation of the condensate was examined using semi-quantitative X-ray fluorescence (XRF) analysis. The XRF results describe the relative elemental composition of the dried residue and must not be interpreted as aqueous concentrations or as evidence of compliance with water-quality standards. The recovery system includes a nominal 0.5 µm polypropylene sediment cartridge, activated-carbon filtration, and a Crystolite^® treatment medium. Because paired measurements before and after treatment were not performed, the removal efficiencies of these components were not determined. The recovered water is subsequently stored and processed in a dual-tank configuration: a primary 3300 L storage system and a secondary 200 L tank used to prepare fertilizer-amended condensate for ornamental-plant irrigation. A fully water-soluble monopotassium phosphate fertilizer (MKP, 0 (–52–34) was incorporated at a gravimetric proportion of 1:10 (1 g MKP per 10 g recovered condensate water). Full article

This study evaluated potentially toxic element (PTEs) contamination (As, Cd, Co, Cr, Cu, Ni, Pb, and Zn) in soil and grapevine leaves across 36 sites in a historical vineyard near Iași, Romania, transitioning toward residential development. Soil samples were analyzed using energy-dispersive X-ray fluorescence (ED-XRF), while leaf tissues collected during the véraison stage (mid-August) underwent microwave-assisted acid digestion followed by inductively coupled plasma mass spectrometry (ICP-MS). Soil analyses revealed that average concentrations of Cr, Ni, and Pb exceeded national normal legal thresholds, while Cu and As surpassed alert permissible limits. Contamination factor ($CF$) and Geoaccumulation Index ($I_{geo}$) metrics confirmed significant anthropogenic Cu enrichment from historical viticultural treatments. Soil-to-leaf transfer factors ($TF$) approached or exceeded 1 for Cu and Zn, though grapevine was not identified as a hyperaccumulator. Spearman correlation modeling demonstrated a statistical decoupling between soil concentrations and foliar tissue levels for Cu ($r_s=-0.21$) and Zn ($r_s=0.075$), confirming that canopy accumulation is governed by historical agrochemical spraying and atmospheric deposition rather than root-driven uptake. Conversely, Pb ($r_s=0.43$) exhibited a moderate direct soil-to-leaf pathway. The potential ecological risk ($PER$) index indicated moderate-to-considerable cumulative risk, primarily driven by Cu ($E_{Cu}=68.64$) and Cd ($E_{Cd}=59.17$). Human health risk assessments established direct ingestion as the primary exposure pathway, with current non-carcinogenic hazards remaining within tolerable limits ($HI<1$). However, the proposed residential conversion increases exposure risks for vulnerable cohorts, underscoring the necessity of systematic soil screening and remediation prior to land redevelopment. Full article

Shanxi Province in China is one of the world’s major bauxite producers. The co-existence of coal and bauxite mining makes this province particularly prone to acid mine drainage (AMD) and, thus, a significant area for investigating heavy metal mobility in an aluminum-rich geological environment. In this study, heavy metal leaching from bauxite under simulated AMD conditions and the geochemical mechanisms controlling their mobility were examined in this study. XRF analysis demonstrated that the bauxite is predominantly composed of Al₂O₃, Fe₂O₃ and SiO₂, while XRD, FTIR, and SEM-EDS revealed that diaspore and kaolinite dominate bauxite, together with accessory Fe- and Ti-bearing phases, providing reactive surfaces for adsorption and precipitation. After batch leaching with synthetic acidic sulphate solutions (pH = 3), Ca(OH)₂ neutralization was regulated. The data reveal that pH is the key factor controlling heavy metal mobility. Acidic conditions enhanced metal release while alkaline conditions favored hydroxide precipitation, surface complexation and co-precipitation. The removal efficiency was 91%–99% for Cd and Zn, 100% for Cd and Zn, 69%–90% for Cr, 35%–100% for Cu, 92%–100% for Ni and up to 100% for Pb. The chemical and mineralogical composition played an indirect role by providing adsorption sites but did not prevent the release of metals under acidic conditions. These results reveal that pH adjustment is the major mechanism controlling heavy metal immobilization in AMD-impacted bauxite systems and contributes to the knowledge of geochemical processes controlling metal mobility in acidic mine drainage. Full article

This study investigates the effect of adding silicon (Si) and cadmium (Cd) elements to AM60 (Mg) magnesium alloy on its corrosion and tribocorrosion (abrasive wear) properties at pH 2.4. Optical Microscopy (OM), X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDX), SEM mapping, and SEM line methods were applied to the alloys. Additionally, the effect of Cd addition on the alloys was investigated using potentiodynamic polarization corrosion in a medium containing CH₃COOH (vinegar) at pH 2.4 (acetic acid) and 20 N and 40 N reciprocal abrasive wear tests in the same medium. The hardness of alloy A1 was determined to be 58.6 HV. Hardness increased by 0.92% in alloy A2, 4.18% in alloy A3, and 10.66% in alloy A4, with the hardness increase occurring as Cd content increased. In potentiodynamic corrosion tests, the corrosion rate (CR) increased with increasing Cd content. In abrasive wear tests, Cd addition increased the abrasive wear rate, and the alloys were ranked in order of increasing wear as follows: A1 < A3 < A2 < A4. These results will contribute to the automotive, aerospace, agricultural, construction, and machinery industries operating in acidic environments, as well as to the scientific literature. Full article

Soils developing in ultramafic (serpentinite) provinces are naturally enriched in Mg, Ni and Cr, which makes it difficult to separate the natural geochemical background from technogenic contamination near chrysotile asbestos mining operations. This problem is examined for the agricultural soils in the impact zone of the Zhitikara chrysotile asbestos quarry (Kostanay Region, Kazakhstan), one of the largest such operations in the world. The elemental composition of the soils was characterised by portable X-ray fluorescence, verified against ICP-OES, and complemented by X-ray diffraction. When contamination was assessed against the global crustal background (upper continental crust), nickel and chromium appeared enriched; however, relative to the local geochemical background, these elements fall within the natural lithogenic range, showing that global crustal values generate false-positive contamination signals in ultramafic terrains. Magnesium was the only element enriched above the local background and the only one that decreased systematically with distance from the quarry, identifying it as the most sensitive tracer of aerogenic serpentinite dust among the elements measured. The discordance between total and acid-soluble chromium is consistent with chromium being hosted mainly in a refractory chromite phase, so that total chromium contents overestimate the environmentally relevant fraction. The study demonstrates the pitfall of applying global crustal backgrounds in ultramafic provinces and supports a locally referenced, differentiated approach to soil-contamination assessment in such settings. Full article

Linzi was a pivotal bronze mirror production centre during the Western Han dynasty (202 BCE–8 CE). This study analyses 71 excavated bronze mirrors from Linzi via pXRF, PCA, and geometric median statistics to investigate elemental characteristics, ore provenance, and the ‘Jin liuji’ (Six Recipes of Bronze). Their alloy compositions exhibit continuity throughout the Warring States (475 BCE–221 BCE) and Western Han periods and are distinct from those in other regions of China during the same period, suggesting that the ‘Jin liuji’ possesses strong regional characteristics specific to the Qi state. Trace element analysis reveals that the copper ore supply experienced three stages, namely diverse and scattered sources (or recycling) during the Warring States period, a transition during the early Western Han, and a concentrated supply during the middle and late Western Han. This study demonstrates the strong intervention of the Han dynasty’s state economic policies in the allocation of local metal resources, providing empirical evidence for reconstructing the economic control network of the unified empire. Full article