Search Results (155)

Land surface temperature (LST) and its diurnal variation are critical for understanding the surface energy balance and water cycle processes. Traditional diurnal temperature cycle (DTC) models are widely used to reconstruct continuous temperature sequences from sparse satellite observations. However, these models rely on the idealized assumption of an isotropic surface and ignore the thermal radiation directionality caused by viewing geometry, which introduces substantial errors over heterogeneous surfaces. Thus, incorporating angular effects into DTC modeling has become an effective approach to improving LST simulation accuracy. This review traces the progress of DTC models from isotropic to anisotropic representations. First, we summarize the development and inherent limitations of conventional isotropic DTC models. Then, we synthesize representative angular-coupled models, ranging from early simple component-based models to recent kernel-driven coupling methods, and compare their physical assumptions, data requirements, parameter complexity, and applicable scenarios. Although these coupled models can significantly improve fitting accuracy over heterogeneous surfaces, they still face challenges. These include strict data requirements, limited all-weather applicability, a lack of nighttime angular correction, and incomplete validation systems. Future research can advance through multi-source data fusion, hybrid modeling strategies, and robust validation systems. These are key to generating high-precision, spatiotemporally consistent LST data. Full article

Coastal systems are vital to human societies, delivering numerous ecosystem services. However, human activities introduce contaminants, especially trace metals (TM) that contribute to their degradation. These environments are inherently dynamic and complex, characterized by rapidly occurring biogeochemical processes. As a consequence, high-frequency sampling is required to evaluate short-term TM dynamics. The hourly temporal variations in nine TM (V, Mn, Ni, Cu, Zn, Cd, Pb, Co and U) concentrations and size-partitioning (<0.02, <0.2 µm, raw sample and in the suspended particulate matter) were investigated during a 27 h diurnal cycle within the Arcachon Bay (SW France). The results demonstrated that: (i) the TM were mainly represented in the potentially bioavailable fraction (<0.02 µm), except for Pb which remained predominantly associated with the particles, (ii) the temporal variability for U and V was only due to the mixing of water bodies contrarily to the 7 other TM, (iii) there was no clear influence of daytime conditions on TM concentration and/or size-partitioning, and (iv) a superimposition of multiple processes controlling TM speciation. Finally, the calculated risk quotients for species demonstrated an ecological risk for the marine biota for Co and Cu. These findings highlight the importance of high-frequency sampling combined with size-fractionation approaches to better resolve TM speciation dynamics, thereby helping to address the persistent knowledge gap in the distribution and biogeochemical cycling of TM between particulate, colloidal and truly dissolved phases in aquatic systems. Full article

As a critical trace gas and a sensitive indicator of climate change, water vapor (H₂O) plays a pivotal role in regulating the Earth’s radiative budget and middle-atmospheric chemical cycles. In this study, H₂O measurements from the Sounding of the Atmosphere using a Broadband Emission Radiometry (SABER) instrument on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite are analyzed to characterize the H₂O spatiotemporal distribution throughout the stratosphere–mesosphere–lower thermosphere (SMLT) region. Using eigen analysis, the bimonthly mean H₂O across different latitude bins between 2002 and 2025 is decomposed into four empirical orthogonal functions (EOFs). Results indicate that stratospheric water vapor remains relatively stable with weak latitudinal dependence, whereas H₂O in the mesosphere–lower thermosphere (MLT) at middle-to-high latitudes exhibits pronounced seasonal variations and distinct hemispheric antisymmetry. The first mode captures a global H₂O long-term increasing trend. Both EOF1 and EOF2 are associated with solar activity and the El Niño–Southern Oscillation (ENSO) to varying degrees, indicating that these dominant modes are driven by multiple concurrent forcing factors. EOF3 correlates with the Quasi-Biennial Oscillation (QBO), suggesting links to QBO-driven atmospheric dynamical processes, whereas EOF4 demonstrates no significant associations with natural activity indices, suggesting perturbations arising from alternative atmospheric mechanisms. By systematically applying EOF analysis to a 24-year dataset of H₂O observations in the SMLT region, this study characterizes the principal distribution patterns and evolutionary characteristics of SMLT H₂O. Through correlation analyses with natural forcing indices, the complex driving mechanisms governing its variability are elucidated. This work provides a comprehensive observational framework for SMLT water vapor variability, enhancing assessments of SMLT H₂O responses to long-term climate change and refining the understanding of the Earth–atmosphere system. Furthermore, these findings provide critical data support for the subsequent development and optimization of SMLT water vapor models. Full article

The removal of excessive amounts of antibiotics from water systems is of great benefit due to their adverse effects on the ecosystems, living organisms and the persistent increase in antibiotic resistance cases. This study was focused on the adsorption of vancomycin from a simulated aqueous medium using seaweed, a sustainable and low-cost adsorbent. Also, the work focuses on assessing the influence of surface modification on adsorption behaviour and determining if chemical treatment provides improvements over untreated seaweed. In particular, chemically modified seaweed and raw (non-modified) seaweed were assessed as adsorbents suitable for removing traces of vancomycin from water, as gauged from the results of High-Performance Liquid Chromatography (HPLC). In addition, Scanning Electron Microscopy (SEM), Fourier Transform Infrared spectroscopy (FT-IR) and the pH point of zero charge (pH_pzc) were used to measure the surface characteristics of these adsorbents. The degree of antibiotic adsorption was evaluated as a function of different factors, including the pH, adsorbent dosage, contact time, ionic strength and initial concentration of vancomycin. Thermodynamic parameters, such as the enthalpy change (∆H°), the entropy change (∆S°) and the free-energy change (∆G°), were calculated. The FTIR analysis indicates that functional groups, such as carbonyl and hydroxyl groups, were involved in the adsorption process, and their modification influenced adsorption behaviour. It was observed that the adsorption of vancomycin by the modified seaweed was slightly lower (±94%) compared to the level achieved for the raw seaweed (±97%). These figures were obtained with an initial concentration of vancomycin of 25 mg/L, a pH of the aqueous solution of 7.0, an adsorbent dose of 0.2 g and a contact time of 120 min. The results showed that untreated seaweed exhibited slightly higher adsorption efficiency than the treated seaweed, suggesting that chemical modification might not have enhanced adsorption performance. The thermodynamic parameters suggested that the adsorption process was exothermic and that adsorption was favourable for the untreated seaweed and less favourable for the treated seaweed. Regeneration studies showed a decrease in adsorption efficiency over repeated cycles. Although the adsorption capacity is lower than that of advanced nanomaterials, the use of seaweed offers an advantage in terms of low cost, availability and environmental sustainability. The comparable efficiency of the modified and untreated seaweed adsorbent suggests that seaweed adsorbents can be used as viable bio-adsorbents for the decontamination of water. Full article

Sandstone of the Lower Cretaceous Luohe Formation is the main water inrush source in the Binchang Mining Area in the southwestern Ordos Basin. Its sedimentary environment and provenance features are critical for local coal development and safe mining. The Luohe Formation at Xiaozhuang Coal Mine comprises three vertical members: the lower member dominated by coarse- to medium-grained sandstones, the middle member mainly composed of fine-grained sandstones, and the upper member characterized by interbedded fine- to medium-grained sandstones and sandy conglomerates. This subdivision newly identifies a complete hydrodynamic evolutionary cycle of depositional environments from high-energy to low-energy and back to high-energy conditions. Integrated petrographic observations and analyses of major and rare earth elements first confirm that the tectonic affinity of the Luohe Formation progressively shifted from a passive continental margin to an active continental margin, accompanied by a corresponding transition in sediment provenance from the North China Craton to a magmatic arc source region. Trace element compositions precisely indicate that the Luohe Formation was deposited in a fluvial freshwater environment under hot, arid, and oxidizing conditions, thus providing new constraints on the paleoenvironmental evolution of the region. Full article

The urgent need to decarbonize the global cement industry is compounded by the declining availability of conventional supplementary cementitious materials (SCMs). Limestone-calcined clay cement (LC3) emerges as a highly sustainable alternative, enabling up to 50 percent clinker replacement and an approximate 40 percent reduction in carbon dioxide emissions. Unlike existing reviews that focus on basic material properties, this paper critically bridges the gap between fundamental hydration thermodynamics and next-generation sustainable engineering applications. Through a structured bibliographic analysis of 135 contemporary sources published between 2000 and 2026, it traces the evolution of LC3 from a laboratory innovation to a highly promising solution for large-scale industrial implementation and circular economy integration. The discussion highlights the synergistic alumina carbonate reaction. This reaction forms carboaluminate phases. These phases significantly densify the microstructure and enhance long term durability. Key engineering properties are examined, contrasting rheological challenges from high water demand and carbonation susceptibility against its exceptional chloride resistance in aggressive environments. The transition to field application is thoroughly assessed, emphasizing technological advances in flash calcination, environmental footprint reduction through life cycle assessment (LCA), and production scalability. Finally, rather than restating known challenges, this review exposes the limitations of current empirical mitigation strategies. It proposes a targeted research agenda focused on molecular-level green admixture design and field calibrated durability models to support the integration of LC3 into emerging sustainable technologies such as 3D concrete printing. Full article

The integration of Geographic Information Systems (GISs) with hydrologic science has evolved over seven decades from manual catchment delineation and output visualization to AI-native spatial water intelligence, reshaping how the water cycle is observed, modeled, and managed. This review explores that evolution, from the progressively tightening coupling between GIS software and hydrologic models to an AI-assisted future in which the line between these two fields blurs and eventually dissolves completely. The evolution of GISs in hydrology is traced through four eras, stratified as: (1) the formalization of governing equations and digital terrain representations (1950–1985); (2) the initial GIS–model coupling era and the rise in watershed simulation (1985–2000); (3) open source and the start of the open data deluge (2000–2015); and (4) machine learning and cloud-native computing (2015–present). A four-level vision for the role of artificial intelligence in the next generation of spatial hydrology is then articulated, from AI-assisted GIS operation to spatially aware AI water intelligence that reasons directly over geospatial data without requiring a traditional GIS or simulation software as an intermediary. Broader limitations and challenges are also discussed. Full article

Trace amounts of H₂O are inevitably introduced during lithium battery manufacturing processes, which induces the hydrolysis of LiPF₆, leading to HF formation, which triggers a cascade of deleterious reactions that degrade the solid electrolyte interphase (SEI) and corrode electrode materials. In this work, a water-scavenging electrolyte was constructed by employing a boroxine-linked covalent organic framework (COF) as the suspended phase. The ring-opening reaction of the boroxine ring units in COFs can effectively capture H₂O, thereby suppressing the hydrolysis of PF₆⁻ and mitigating electrode corrosion caused by HF. Consequently, a Li-metal battery with a high-nickel cathode retained 73% of its initial capacity after 500 cycles at 1 C, and a silicon-based lithium-ion battery with a high-nickel cathode sustained stable cycling over 500 cycles at a high rate of 10 C. This suspension strategy, leveraging a boroxine-linked COF with dual H₂O-scavenging capability, offers a scalable and versatile platform for electrolyte engineering toward practical next-generation lithium batteries. Full article

The oxygen-evolving complex (OEC) of Photosystem II (PSII) catalyzes light-driven water oxidation, a process necessary to sustain Earth’s atmospheric oxygen. Oxygen yields measured during single-turnover flash sequences exhibit period-four oscillations, which form the basis of the Joliot–Kok (S-state) model. However, when the oscillations of other processes contribute to the measured oxygen yield, fitting methods can conflate these signals and distort estimates of inefficiencies and initial S-state populations. To address this, we applied the empirical wavelet transform (EWT) as a model-independent method to separate overlapping oscillators and capture damping dynamics that are not well represented in Fourier analysis. We tested this framework on polarographic flash-oxygen traces from both our Synechocystis sp. PCC 6803 thylakoid membrane preparations and archival datasets on Chlorella and isolated chloroplasts. EWT consistently resolves the expected period-four component alongside a distinct binary oscillation. Simulations suggest that fitting this isolated period-four signal recovers VZAD parameters more accurately than analysis of raw traces, yielding different estimates for S-state distributions and transition probabilities. Notably, this binary oscillation aligns closely with semiquinone dynamics predicted solely from period-four fit parameters. These findings indicate that EWT can effectively distinguish complex signals in oxygen evolution, offering a framework potentially applicable to other spectroscopic probes of the S-state cycle. Full article

Water is essential for human life, and access to clean water is considered a basic human right by the United Nations. Around the world, a high proportion of the population still does not have access to safe fresh water, with high impact on health. This situation perpetuates a cycle of poverty, hindering economic development and exacerbating inequality. Water is considered unsafe to drink if it is contaminated. The contamination can be categorized into three types: physical, chemical, and biological. Biological contamination arises from the presence in water of living organisms such as bacteria, viruses, algae, fungi, and parasites. Recently, the scientific community has raised the alarm on contamination caused by a large group of bacteria known as Cyanobacteria, which can release harmful toxins into water, including cyanotoxins like microcystin-LR (MC-LR). Currently, the standard analytical procedure for the detection and quantification of MC-LR relies on chromatography-based techniques (HPLC, LC/MS, GC/MS), immunological assays (ELISA), or protein phosphatase inhibition assays (PPIAs). In this study, we used fluorescence correlation spectroscopy (FCS) methodology to develop a competitive assay for detection of traces of the MC-LR toxin in a water solution. A conjugated form of bovine serum albumin (BSA) with MC-LR was labeled with the fluorescence dye CF488 (MC-LR BSA 488). The diffusion coefficient values of the MC-LR BSA 488 complex were investigated in the absence and in the presence of MC-LR. The change in the value of the diffusion coefficient was correlated with the concentration value of MC-LR in solution. The results showed a limit of detection (LoD) of the assay of 0.18 nM (0.18 µg/L), a value lower than the limit value (1.0 μg/L) established by the World Health Organization (WHO). Full article

Soil moisture regulation is critical for vegetation restoration in arid ecosystems. Polymeric hydrogels, notably polyacrylic acid (PAA) and polyacrylamide (PAM), are widely employed as water-retaining agents to enhance soil water availability. However, the coupling between their distinct chemical structures and key performance metrics, particularly cycling stability and water retention kinetics in desert substrates, remains unclear. In this work, we present an integrated experimental–computational study to establish a “molecular structure–interfacial behavior–macroscopic property” framework for PAA and PAM. The results show that PAA exhibits a higher equilibrium water absorption (WAC ~242 g/g) and more stable water uptake capacity under cycling, whereas PAM displays much higher zero-shear viscosity and pronounced shear thinning with a yield plateau (~30 Pa). DFT and MD simulations trace these macroscopic disparities to their distinct electronic structures and hydration dynamics. Specifically, PAA’s strong electrostatic interactions and extended chain conformations promote a more rigid and ordered hydration shell, whereas PAM adopts a compact structure with greater chain mobility, resulting in a less ordered hydration layer. Collectively, these findings provide a structure-property framework for the scientifically grounded selection of water-retaining agents. The integrated experimental–computational methodology presented herein establishes a predictive framework for the rational design of functional materials in arid land restoration. Full article

Geosmin contamination in water is a worldwide concern, owing to its strong odor at trace levels and limited removal by typical water treatment methods. In this study, bentonite–alginate–magnetic (Bent-alg-mag) beads were prepared using the ionic gelation method for the removal of geosmin from aqueous solutions. The adsorbent’s physicochemical properties were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. The influence of factors such as contact time, solution pH, initial geosmin concentration, and adsorbent dosage on adsorption performance was systematically investigated. Under optimal conditions, over 96% of geosmin was removed within 480 min. The adsorption kinetics were best described by the pseudo-first-order model (R² = 0.9918), indicating that the process is primarily controlled by surface adsorption. Adsorption equilibrium data were well fitted by the Langmuir isotherm model (R² = 0.9705) and a maximum monolayer capacity of 16.064 ng/g. The adsorbent exhibited 70% removal efficiency after three adsorption–desorption cycles, showing good regeneration potential, though long-term stability may be limited. Overall, the Bent-alg-mag beads proved to be an effective and promising material for the removal of geosmin from water. Full article

The removal of toxic trace metals such as cadmium (Cd²⁺) and lead (Pb²⁺) from wastewater is critical due to their persistence, bioaccumulation, and adverse health effects. In this study, a novel composite adsorbent was synthesized by integrating activated carbon with nickel–iron-layered double hydroxides (NiFe-LDH) and immobilizing the resulting nanocomposite within Polyether sulfone (PES) beads to improve stability, handling, and recyclability. The material was evaluated under varying pH, initial metal concentration, and contact time conditions. The adsorption behavior was investigated using four isotherm models and two kinetic models. The composite beads exhibited maximum adsorption capacities of 1.784 mg g⁻¹ for Cd²⁺ and 5.882 mg g⁻¹ for Pb²⁺. The Cd²⁺ adsorption followed the Langmuir isotherm model (R² = 0.995), indicating a homogeneous monolayer adsorption, whereas Pb²⁺ adsorption was best described by the Freundlich model (R² = 0.955), suggesting heterogeneous surface interactions and multiple binding sites. The kinetic analysis showed that the adsorption of both metals followed a pseudo-second-order model, supporting chemisorption as the dominant rate-controlling mechanism. The AC@NiFe-LDH/PES beads demonstrated high efficiency, structural integrity, and ease of recovery over multiple cycles, highlighting their potential as a sustainable and environmentally friendly adsorbent for trace metal removal from contaminated water. Full article

The South Sakhalin mud volcano (Sakhalin Island, Russia) emits HCO₃-Cl/Na-Mg water, emanates CO₂ prevailing over CH₄ in the gas phase, and extrudes mud bearing five carbonate mineral species. The study focuses on the distribution, diversity, and origin of the carbonate minerals from the mud volcano (MV) ejecta, in terms of carbon cycle processes. The data presented include a synthesis of field observations, compositions of MV gases and waters, chemistry of carbonate minerals, as well as stable isotope geochemistry of MV waters (δ¹³C, δD, and δ¹⁸O) and carbonates (δ¹³C and δ¹⁸O). The sampled MV waters are isotopically heavy, with δ¹⁸O = +5.7‰ to +7.5‰ VSMOW, δD = −18.0‰ to −11.0‰ VSMOW, and ¹³C (δ¹³C_DIC = +6.9‰ to +8.1‰ VPDB). This composition may be due to the dilution of basinal water with dehydration water released during the diagenetic illitization of smectite. Carbonates in the sampled mud masses belong to three genetically different groups. Mg-rich siderite, (Fe_0.54–0.81Mg_0.04–0.30Ca_0.05–0.23Mn_0.00–0.08)CO₃, disseminated in abundance throughout the mud masses, coexists with common calcite and sporadic ankerite. The trace-element chemistry of Mg-siderite, as well as the oxygen (δ¹⁸O = +34.4‰ to +36.8‰ VSMOW) and carbon (δ¹³C = −1.3‰ to +0.6‰ VPDB) isotopic signatures, confirms its authigenic origin. Siderite formed during early diagenesis of the Upper Cretaceous sandy and clayey marine sediments mobilized by mud volcanism in the area. Another assemblage, composed of dawsonite, siderite, and vein calcite (±kaolinite), represents altered arkose sandstones found as few fragments in the mud. This assemblage may be a marker of later CO₂ flooding into the sandstone aquifer in the geological past. The trace-element chemistry, particular morphology, and heavy C (δ¹³C = +5.5‰ to +7.0‰ VPDB) and O (δ¹⁸O = +39.1‰ to +39.5‰ VSMOW) isotope compositions indicate that aragonite is the only carbonate species that is related to the current MV activity. It crystallized in a shallow reservoir and was maintained by CO₂ released from rapidly ascending liquefied mud and HCO₃-Cl/Na-Mg-type of MV waters. Full article

The article presents a comprehensive comparative performance evaluation and validation of composite adsorbents based on the Se-derivative of 4-amino-N′-hydroxy-1,2,5-oxadiazole-3-carboximidamide for U (VI) recovery from complex multicomponent aqueous media. Our results indicate the composite materials to be comparable to, and in some cases to surpass, existing adsorbents in recovery efficiency. Under static sorption conditions for trace U (VI) from real multicomponent solutions (tap, river, and sea water), the sorption efficiency reached 80–98%, while the distribution coefficients ranged from 10⁴ to 10⁶ cm³ g⁻¹. The sorption-selectivity properties of the materials were evaluated in the presence of competing ions (EDTA and oxalate ions), which possess a high chelating capacity and a strong tendency to form complexes with uranium. The dependence of sorption efficiency on the concentration of these ions and the solution pH was investigated. The possibility of reusing the materials over multiple sorption-desorption cycles was assessed. An optimal regenerating eluent agent was identified (NaHCO₃/NH₄NO₃), providing a desorption efficiency of >95% without degrading the material’s sorption properties over repeated cycles. Using a combination of physicochemical methods, including sorption techniques, the mechanism of uranium sorption and its dependence on the material structure were determined. The efficiency of uranium recovery from multicomponent natural waters was also investigated under dynamic conditions over repeated sorption-desorption cycles. The results demonstrate through comparative analysis that the developed composites exhibit a high sorption capacity and possess a high practical potential for the concentration and recovery of uranium from high-salinity solutions with complex composition. Full article