Search Results (489)

Using perfluorooctanoic acid (PFOA) as a representative highly mobile solute to isolate hydrological controls, we investigated how slope influences the partitioning of vertical and lateral transport pathways. While vertical percolation has been widely examined using conventional column leaching tests, lateral transport driven by topographic gradients remain insufficiently quantified under controlled conditions. Here, laboratory-scale inclined leaching experiments were conducted to resolve the distribution of solute transport among vertical leachate, lateral runoff, and solid-phase retention under systematically varied slope angles (0°, 4°, 9°, and 20°), flow regimes, and leaching volumes. Results show that solute migration shifted from vertical-dominated transport under flat conditions (91% at 0°) to lateral-dominated export at moderate slopes, with lateral pathways accounting for up to 75% of the recovered mass at 9°. This pathway shift was well described by an exponential partitioning model, f₁(α) = f_max (1 − e^−kα), where f_max = 0.80 and k = 0.34°⁻¹ (R² = 0.97), indicating a critical crossover threshold at approximately 4° slope. Flow regime interacted with slope angle to modulate lateral transport efficiency: slower flow enhanced lateral export at moderate slopes, whereas faster flow promoted peak lateral transport under steeper conditions. In contrast, solid-phase retention remained consistently low (5–9%) across all treatments, indicating that the observed redistribution patterns were primarily governed by hydrological pathway partitioning rather than sorption processes. These results demonstrate that even modest topographic gradients can fundamentally alter solute transport pathways in sloped soils. The slope-dependent pathway partitioning framework developed here provides a process-based basis for incorporating lateral transport into hillslope hydrological models and for improving assessments of contaminant redistribution in both managed and natural landscapes. Full article

Oxybenzone (BP-3) and polystyrene microplastics (PS MPs) are pervasive aquatic contaminants whose combined biological effects remain insufficiently characterized. This study investigated co-exposure to BP-3 and PS MPs in zebrafish embryos (Danio rerio), focusing on developmental endpoints, tissue bioaccumulation, and time-dependent sorption behavior. Embryos were exposed to 0.10–1.50 mg/L BP-3 for 96 h in the presence of PS MPs. Mortality, developmental abnormalities, and tissue BP-3 concentrations were measured, and chemical analysis was performed by HPLC-DAD. Although mortality was not significantly affected, embryos exhibited developmental abnormalities, particularly in swim bladder formation. Tissue BP-3 accumulation increased with exposure concentration. The influence of PS MPs on BP-3 uptake was concentration-dependent: at lower BP-3 exposures, PS MPs reduced tissue accumulation, whereas at higher exposures this reduction became negligible or was no longer observed. This suggests a dual role for PS MPs: mitigating direct aqueous exposure by sequestering BP-3 yet simultaneously acting as potential vectors for its environmental persistence and trophic transfer through alternative pathways. Independent time-resolved experiments showed rapid BP-3 removal from the aqueous phase in the presence of PS MPs, with early stabilization consistent with rapid partitioning behavior. These findings highlight the complex interactions between emerging contaminants and MPs, underscoring the need for further research into their ecological implications. Full article

Recovery of scandium from chloride-bearing process liquors formed during titanium–magnesium production remains constrained by trace-level metal content and chemically aggressive solution matrices. Within the present study, the retention behaviour of Sc³⁺ species in strongly acidic chloride media was examined through batch-mode interaction with gel-type sulfonated cation exchangers, namely KU-2-8, Lewatit SP112H, Purosorb SAC140H, and Purolite C-150H. Quantitative evaluation of sorption efficiency was performed by calculating equilibrium uptake (q_e), phase distribution factor (K_d), and percentage recovery (R). Under identical liquid–solid ratios, the Lewatit SP112H matrix exhibited superior affinity toward dissolved scandium, achieving q_e = 179.82 mg/g and K_d = 172.41 mL/g. Equilibrium fitting procedures revealed that scandium uptake by Purosorb SAC140H conforms to monolayer-type retention described by the Langmuir formalism (R² = 0.9786), whereas sorption on Lewatit SP112H proceeds over energetically non-uniform sites and is more adequately represented by Freundlich and Dubinin–Radushkevich approximations. The observed retention characteristics establish a selection framework for ion-exchange media applicable to scandium concentration from acidic chloride hydrometallurgical streams. Full article

The manuscript describes an optical sensing microplate for the high-throughput screening of imidazolinone herbicides in soil extracts. As far as we know, imprinted proteins (IPs) specific to imidazolinone herbicides have not been synthesized and used as a recognition element for their solid-phase extraction before. Imprinted bovine serum albumin (BSA) and glucose oxidase (GOx) were synthesized in the presence of imazamox as a template and then these IPs were immobilized at the bottom of microplate wells. The sorption capacity (Q) of aminated silica nanoparticles modified by IPs (IP–BIS) was 6.38 mg g⁻¹ while the imprinting factor ($IF$) equaled 2.6. The concentration of imazamox was determined by a “turn-off” solid-phase assay using alloyed CdZnSeS/ZnS quantum dots (QDs) as a component of fluorescent substrate. Alloyed CdZnSeS/ZnS QDs were stabilized in an aqueous phase by positively charged cysteamine that, as far we know, had not been used as this type of ligand before. Our method allows for determining the concentration of imazamox in the range of 0.5–9.2 μg mL⁻¹, with a limit of quantification limit of quantitation (LOQ) equal to 0.45 μg mL⁻¹ The sensing microplate enables parallel detection of up to 96 samples containing herbicides using standard fluorescence microplate readers or smartphones. The paper describes how such sensing microplates can be used for the analysis of artificially contaminated soil samples. The proposed approach combines pre-concentration of analyte at the IPs with its subsequent determination on a single analytical platform, thus allowing for both highly sensitive determination in laboratory conditions and mass screening in the field. Full article

Co/Fe layered double hydroxides (LDHs) are among the most promising materials for advanced industrial and energy applications. Controlling the synthesis conditions of LDH materials is thus crucial to precisely tailoring cation composition and distribution, thereby regulating surface charge, ion sorption, and electron transfer required for optimal chemical and electrochemical performance. Therefore, characterizing Co/Fe precipitates (chemical composition, purity, morphology, and crystallinity) is also required to further exploit their controlled properties. Thus, solids with Co/Fe cation ratios between 2/2 and 10/2 were synthesized under an air atmosphere, at pH 8 or 11.5. For the first time, multiscale physicochemical techniques (FTIR, TEM-EELS, SEM, AAS, TGA, CHN elemental analysis, and XRD complemented by Rietveld refinement) were used to provide a fully documented characterization of the structure, texture, purity, chemical composition, and thermal properties of Co/Fe LDH-based materials. The combined interpretation of data from these complementary techniques enabled the precise identification and chemical characterization of the mineralogical phases formed. Both acid–base and redox reactions govern the overall Co^II/Fe^III LDH formation process. Well-crystallized LDHs were synthesized, except for the 2/2 ratio at pH 11.5, which led to the formation of α-Co(OH)₂, γ-Fe₂O₃, and Co₃O₄ byproducts. A pH value of 8.0 provides valuable LDH materials made of quasi-hexagonal particles with diagonal lengths between 200 and 500 nm. Rietveld refining showed the presence of LDH phases in the range of 95–98%. Multiple local chemical analyses using EDX on chosen particles demonstrated pure 4/2 and 6/2 LDHs. For the 2/2 ratio, the cumulative mass fraction of two LDH-type products consistently reached 97%, distributed between Co/Fe 1.5/2 (71%) and Co/Fe 4/2 (29%). For the 10/2 ratio, only partial Co precipitation was observed, forming 95% Co/Fe LDH phases distributed between Co/Fe 10/2 (72%) and 7/2 (28%). Full article

Boron nitride is considered a promising material for solid-state hydrogen storage due to its high thermal and chemical stability up to ~1000 °C, depending on the atmosphere, as well as its ability to form defect-rich structures with enhanced sorption activity. Despite the growing interest in modified BN systems, systematic studies on the effect of multicomponent modification induced by the addition of carbon, titanium, and aluminum on the structural and phase evolution of boron nitride during high-energy mechanical alloying remain limited to date. In this work, the structural-phase and morphological changes in boron nitride-based composites modified by the addition of carbon, titanium, and aluminum, synthesized by high-energy mechanical alloying, were investigated. The structural state and morphology of the materials were analyzed using X-ray diffraction, scanning electron microscopy, particle size analysis, and thermal analysis. It is shown that mechanical alloying leads to a progressive breakdown of the layered hexagonal BN structure and the formation of an amorphous-like, defect-rich state without the formation of new crystalline phases. The main stage of amorphization occurs within 30–60 min, after which structural disordering reaches saturation. Increasing the mechanical alloying time to 120 min does not result in significant changes in the phase state; however, it is accompanied by a reduction in agglomeration and the formation of a more homogeneous powder morphology, characterized by narrower particle size distributions, smoother particle surfaces, and more uniform spatial dispersion of components. It was established that the nature of the added component significantly influences the kinetics of structural transformations: carbon accelerates amorphization, titanium intensifies fragmentation and defect accumulation, whereas aluminum exhibits a stabilizing effect. In multicomponent BN–C–Ti–Al systems, a synergistic combination of these effects is observed, leading to the formation of metastable, partially amorphous structures. Based on a comprehensive analysis of structural and morphological data, the optimal mechanical alloying time was determined to be 120 min, providing a saturated amorphous-like structural state combined with improved microstructural homogeneity. The obtained defect-rich boron nitride structures can be considered a promising basis for further studies in the field of solid-state hydrogen storage. Full article

Per- and Polyfluoroalkyl substances (PFASs) are commonly detected in airport stormwater runoff due to historical and ongoing use of aqueous film-forming foams (AFFFs). Conventional stormwater control measures (SCMs) are generally effective at removing PFASs associated with the particulate fraction, but may provide limited removal of dissolved-phase PFASs. Sorbent polishing beds represent a potential downstream treatment option; however, their applicability and performance for PFASs in stormwater have not been well studied. In this study, measured PFAS concentrations and runoff volumes from an AFFF-affected airport apron were combined with literature-derived sorption parameters to develop a screening-level framework for evaluating adsorber beds as polishing units for SCM effluent. Bed sizing was calculated using a representative empty bed contact time (EBCT) of 10 min and a design volume based on the 85th percentile storm event. Sorbent performance was evaluated using literature equilibrium partition coefficients (K_d) for activated carbons, ion exchange resins, and specialty materials to estimate operational lifetimes prior to regeneration or replacement. Model-based results indicated lifetimes ranging from approximately 7 years for activated carbon to more than 50 years for specialty materials, depending on PFAS chain length and affinity. Sensitivity analysis using quartile K_d ranges showed predicted lifetimes spanning orders of magnitude, emphasizing the screening-level nature of the estimates. This work links field monitoring data with conceptual adsorber design to support early-stage evaluation of sorbent polishing strategies for airport runoff management, supporting compliance under tightening discharge regulations. Full article

The selective removal of radioactive cesium-137 and strontium-90 from high-salinity radioactive wastewater remains a critical challenge, as competing ions reduce adsorption efficiency and selectivity. In this study, high-performance granulated adsorbents were developed based on alkali-activated geopolymer matrices to enhance sorption performance. The adsorbents were synthesized by inorganic polymerization, and mechanically robust granules with controlled porosity and surface chemistry were obtained. Batch sorption experiments conducted in simulated seawater demonstrated greater than 99% removal efficiencies for cesium and strontium. Isotherm modeling confirmed high maximum sorption capacities (up to 0.41 meq/g for Cs⁺ and 5.07 meq/g for Sr²⁺). Continuous fixed-bed column tests demonstrated sustained removal efficiencies for the optimized adsorbents. Structural analyses, including scanning electron microscopy, energy-dispersive X-ray spectroscopy mapping, and X-ray diffraction, confirmed uniform elemental distribution and crystalline phases consistent with selective sorption mechanisms. Assessment of mechanical strength revealed sufficient compressive strengths to ensure operational durability under hydraulic stress. These findings demonstrate that the synthesized geopolymer-based granules are a potentially effective and versatile solution for the comprehensive treatment of radioactive wastewater. Full article

Ni removal from waste streams wherein it is present in organically complexed forms remains a major industrial challenge since organically bound Ni does not readily precipitate and is poorly removed by conventional adsorbents. In this work, two effective adsorbents, namely thin-layered porous carbon (TLPC) and MnO₂-decorated TLPC (i.e., MnO₂-TLPC), were developed for the removal of both inorganic and organically complexed Ni(II) from synthetic and real waste streams. Both adsorbents removed inorganic Ni(II) as well as Ni(II) present in organically complexed forms, achieving up to ~80% removal from both real and synthetic electroplating wastewater. Critically, Ni removal efficiencies were maintained over five adsorption–desorption cycles, demonstrating excellent regeneration and reuse potential. The Ni removal by TLPC was pH-dependent, whereas MnO₂-TLPC showed minimal pH sensitivity. TLPC relies on outer-sphere, charge-driven adsorption, whereas MnO₂-TLPC achieves stronger Ni binding through inner-sphere complexation promoted by oxygen- and nitrogen-based functional groups. The sorbents also reduced dissolved organic carbon, with TLPC displaying higher organic removal efficiency. Mechanistic analysis indicates that Ni uptake is primarily governed by sorption of both complexed and inorganic Ni(II) present in equilibrium with the complex, combined with sorption of the free ligand itself. The sorption of the free ligands and inorganic Ni(II) drive Ni–ligand decomplexation in the solution phase, enabling further Ni removal. Overall, TLPC provides a low-cost, high-performance option for treating alkaline wastewaters with elevated Ni and organic loadings, while MnO₂-TLPC offers robust, pH-resilient removal under circumneutral conditions. These findings position both materials as promising candidates for practical wastewater treatment applications targeting complexed metal contaminants. Full article

Fe-oxyhydroxides can incorporate toxic metals during the formation of mineral phases in soils and sediments, thereby potentially altering the environmental reactivity of metals and impacting the microbial communities. In this study, isothermal microcalorimetry has been used to monitor the metabolic activity of Pseudomonas putida KT2440 exposed to pure ferrihydrite and to Pb-, Cd-, and As-bearing ferrihydrites under oxygen-limited conditions. Calorimetric measurements of the integral heat released during the exponential growth were combined with the analysis of dissolved iron and heavy metals, as well as the glucose uptake, to understand how heavy metal incorporation modifies mineral reactivity and microbial heat output. Pure ferrihydrite decreased the integral heat by about 45%, primarily due to glucose and phosphate depletion, Fe(III) leaching, and mineral–cell aggregation. Heavy metal dopants were found to modulate nutrient availability, surface charge, and Fe solubilization, which, in turn, influenced the integral heat. Pb-Fh generated the highest ferrihydrite dissolution and metabolic heat, with a maximum effect at intermediate substitution levels. As-Fh induced moderate Fe release and metabolic activity, consistent with the enhanced phosphate sorption and lowered surface charge. Cd-bearing Fh showed minimal reactivity and yielded the lowest heat output. Microcalorimetry was proven useful for unraveling microbe–mineral interactions in complex contaminated environments. Full article

The separation of rare earth elements (REEs) with similar chemical properties remains a relevant challenge today, most often addressed using liquid–liquid and solid-phase extraction with various chelating agents. Excellent complexing agents for REEs are 1,3-diketones and their analogs. We have for the first time proposed a method for preparing a material consisting of a covalently immobilized 3-acyl-4-hydroxycoumarin ligand on silica. For its synthesis, we employed a strategy based on the “click” reaction of 3-azidopropyl silica with a propargyl-containing coumarin–chalcone conjugate—this approach is the most tolerant and does not affect the coordinationally active fragment of the ligand. The material was characterized by thermal analysis, IR spectroscopy, and ¹³C NMR. The potential of the synthesized material for REE preconcentration was demonstrated at pH 5–5.5: high extraction efficiency for Gd(III), Dy(III), Er(III), Eu(III), Sm(III), and Yb(III) was observed, with fast adsorption kinetics (30 min) and extraction degrees of ~98%. Under unified conditions of static and dynamic extraction for Gd(III), Dy(III), Er(III), Eu(III), Sm(III), and Yb(III), affinity series toward the surface were obtained as a function of the distribution coefficient. It was shown that 10-fold molar excesses of Fe(III), Al(III), Cu(II), Ni(II), and Co(II) allow retention of more than 95% extraction for Dy(III) and Er(III). After adsorption of Dy(III) and Er(III), shifts in the carbonyl group absorption bands are visible in the IR spectra of the material, indicating a chelating mechanism of sorption. Additional studies are required for implementation in analytical and preparative REE separation schemes; however, preliminary data show that the material is a highly active adsorbent. Full article

Magnesium hydride (MgH₂) is a promising solid-state hydrogen storage material owing to its high hydrogen capacity and low cost, yet its practical application is limited by sluggish kinetics, high operating temperatures, and poor cycling stability. Among various catalytic approaches, Fe-based catalysts have emerged as attractive candidates due to their abundance, compositional tunability, and effective promotion of hydrogen sorption reactions in MgH₂ systems. This review critically summarizes recent progress in Fe-based catalysts for MgH₂ hydrogen storage, encompassing elemental Fe, iron oxides, Fe-based alloys, and advanced composite catalysts with nanostructured and multicomponent architectures. Mechanistic insights into catalytic enhancement are discussed, with particular emphasis on interfacial electron transfer, catalytic phase evolution, hydrogen diffusion pathways, and synergistic effects between Fe-containing species and MgH₂, supported by experimental and theoretical studies. In addition to catalytic activity, key stability challenges—including catalyst agglomeration, phase segregation, interfacial degradation, and performance decay during cycling—are analyzed in relation to structural evolution and kinetic–thermodynamic trade-offs. Finally, a roadmap for the scalable design of Fe-based catalysts is proposed, highlighting rational catalyst selection, interface engineering, and compatibility with large-scale synthesis. This review aims to bridge fundamental mechanisms with practical design considerations for developing durable and high-performance MgH₂-based hydrogen storage materials. Full article

Polyurethane (PU) is widely recognized for its efficient oil sorption properties. However, this capacity is highly dependent on its intrinsic chemical composition and morphological structure, which can be altered by mechanical or chemical treatments commonly applied before using it as a sorbent. In this study, we present a comprehensive investigation of the oil sorption behavior of both soft and rigid PU foams, and their blade-milled ground (BMG) counterparts obtained by mechanical treatment of several recycled PU-based products, including seats, mattresses, side panels of cars, packaging components, and insulating panels of refrigerators and freezers. We found that blade milling the soft PU foams leads to a significant reduction in oil sorption capacity proportional to the extent of grinding. Pristine soft PU foams and BMG-PUs with intermediate particle size (−250 μm–1 mm) exhibited the highest oil uptake (20–30 g/g), whereas the finest fraction (5 μm–250 μm) showed a lower capacity (3–7 g/g). In contrast, rigid PU foams showed consistently low oil sorption (~5 g/g), with negligible differences between the original and ground materials. At the macroscopic level, optical and morphological analyses revealed the collapse of the 3D porous network and a reduction in surface area. On the microscopic scale, spectroscopic, structural, and thermal analyses confirmed phase separation and rearrangement of hard and soft segmented domains within the polymer matrix, suggesting a different mechanism for oil sorption in BMG-PU. Despite reduced performance compared to pristine foams, BMG-PU powders, especially those with intermediate dimensions and originating from soft PU foams, present a viable, low-cost, and sustainable alternative for oil sorption applications, including oil spill remediation, while offering an effective strategy for effective recycling of PU foam wastes. Full article

Deep eutectic solvents (DESs) have attracted significant attention as eco-friendly and sustainable alternatives to conventional, often toxic, organic solvents. They are easy to synthesize, and their tunable physicochemical properties enable their application in microextraction techniques for a wide range of analytes. However, some DESs may exhibit thermal instability, and their high viscosity or solubility can influence the extraction efficiency. Despite these limitations, in recent years, DESs have been successfully used in multiple roles in solid-phase microextraction (SPME). They may be used to functionalize or modify sorbent materials, thereby forming composite sorbents with enhanced performance. Moreover, DESs can be combined with polymers to produce hybrid materials with improved extraction capabilities. Additionally, DESs can act as porogens within SPME sorbents, increasing sorption capacity and, consequently, extraction efficiency. They can also serve as green desorption solvents, replacing traditional volatile organic solvents during the recovery of analytes from sorbent materials. This review synthesizes current knowledge on the implementation of DESs in SPME techniques, critically evaluating their primary advantages and inherent limitations. The novelty of this review lies in the assessment of DES-based SPME through the metrics of greenness and sustainable chemistry. Furthermore, the review identifies research perspectives and priorities to advance DES-based SPME, including: the integration of predictive modeling (COSMO-RS, machine learning) to elucidate DES-analytes interactions; the adoption of 3D printing for the precision fabrication of DES-based sorbents; the standardization of DES-based SPME performance; and the exploration of natural DESs for in vivo SPME in biomedical applications. Full article

A method for quantifying tebufenpyrad residues in greenhouse sandy loam soils was developed and validated. Given the strong sorption (high K_oc) of tebufenpyrad to mineral–organic domains in soils, desorption-limited and partially bound residues may occur, so sample preparation methods should actively promote desorption to minimize underestimation. The QuEChERS extraction procedure was optimized by adjusting pre-wetting volume and aqueous medium to enhance desorption prior to salt-induced acetonitrile partitioning. Pre-wetting volume markedly affected phase separation and recovery: acceptable ranges were 80.2–82.0% at 5–10 mL, 94.6% at 15 mL, and 99.1% at 20 mL, while a supra-quantitative value of 119.6% was observed at 25 mL, likely due to salt-induced contraction of the acetonitrile layer, which artificially concentrates tebufenpyrad. Among pre-wetting reagents, 15 mL of 0.05% HCl yielded the highest desorption in field soil (0.20 mg/kg), compared with distilled water (0.13 mg/kg), formic acid (0.16 mg/kg), and EDTA (0.14–0.17 mg/kg). The final method employed 15 mL of 0.05% HCl for pre-wetting, followed by acetonitrile extraction and MgSO₄/NaCl partitioning. Linearity (r² = 0.9990) was achieved over 1.25 to 100 ng/mL, with an LOQ of 0.005 mg/kg and average recoveries of 86.7%, 99.8%, and 98.5% at 0.01, 0.1, and 30 mg/kg, respectively (RSD ≤ 6.2%), satisfying SANTE criteria. In greenhouse soil, residues declined from 1.9 to 0.3 mg/kg at the recommended rate (1×) and from 4.8 to 0.7 mg/kg at the doubled rate (2×) within 46 d (DT₅₀ ≈ 20 d). This validated QuEChERS method provides a reliable analytical basis for evaluating tebufenpyrad dissipation in soil. Full article