Search Results (405)

Direct utilization of biomass-derived silica in neutral surfactant-templated mesoporous synthesis remains underexplored with respect to mesostructure control and functional integration. High-purity silica extracted from acid-treated rice husk ash (~98.4 wt% SiO₂) was employed as the sole precursor in a fluoride-assisted sol–gel route to synthesize MSU-X frameworks without chemical modification. Systematic parametric variation—pH, Si/surfactant ratio, hydrothermal temperature, and aging duration—establishes quantitative structure–processing correlations. Under optimized conditions (pH 2, Si/Tergitol = 8, 60 °C, 96 h), the resulting material exhibits a wormhole-like mesoarchitecture with a BET surface area of 816 m² g⁻¹, mean pore diameter of ~3.6 nm, and three-dimensionally interconnected channels, confirmed by SAXS, TEM, and N₂ sorption. EDXRF analysis confirms effective impurity removal and high silica incorporation efficiency (~95–96%); thermal stability persists to 700 °C, with incipient crystallization near 800 °C. As a functional demonstration, MSU-X served as an anti-agglomeration scaffold for ZIF-8 crystallization during DDT adsorption. Despite attenuated kinetics relative to pristine ZIF-8—where severe agglomeration occludes active imidazole nodes—the Z8/MSU-X composite achieved near-quantitative DDT removal (74.10 mg g⁻¹). This performance stems from the mesoporous matrix driving size-confined, highly dispersed ZIF-8 growth, thereby maximizing active-site exposure. Operating within a reagent-limited regime rather than a capacity-saturated boundary, this efficient depletion confirms that the scaffold successfully suppresses site loss. Ultimately, these findings validate biogenic silica as a directly integrable precursor for tailored mesostructure assembly, positioning agricultural waste as a high-performance feedstock for hierarchical adsorption architectures. Full article

Background/Objectives: Chemosymbiotic bivalves play a fundamental role in deep-sea cold seep and hydrothermal vent ecosystems, where essential long-chain polyunsaturated fatty acids (LC-PUFAs) are scarce. Whether these bivalves retain the capacity for endogenous PUFA synthesis remains poorly understood. Here, we investigated the PUFA biosynthetic capacity of two dominant chemosymbiotic bivalves from the Haima cold seep—the mussel Gigantidas haimaensis and the clam Archivesica marissinica. Methods: Genome and transcriptome assembly revealed three fatty acid desaturase (Fad) genes per species, which phylogenetically clustered into Δ5 (GhFads1, GhFads2; AmFads1, AmFads2) and Δ6/8 (GhFads3, AmFads3) clades, with lineage-specific duplications within the Δ5 clade. Functional assays were performed in yeast to characterize the activity of these enzymes. Results:Both Fads3 enzymes (Δ6/8 clade) convert C20:3n-6 and C20:4n-3 into C20:4n-6 and C20:5n-3, respectively, exhibiting Δ8-desaturase activity. Notably, Δ5-clade isoforms showed divergent substrate specificities: GhFads2 and AmFads1 functioned as classical Δ5-desaturases on PUFA substrates, whereas GhFads1 and AmFads2 specifically desaturated the bacterial monounsaturated fatty acid (MUFA) C18:1n-7 to produce C18:2n PUFAs. Conclusions: Together, our results reveal that cold-seep bivalves retain endogenous LC-PUFA biosynthetic capacity and have evolved duplicated Δ5-desaturases with novel regioselectivity toward bacterial MUFAs, likely representing an adaptive membrane modification for survival under extreme deep-sea conditions. Full article

Microbial fuel cells (MFCs) are promising bioelectrochemical systems for simultaneous wastewater treatment and energy recovery. However, their practical application is still limited by insufficient power output and weak transient energy-supply capability under fluctuating operational conditions. Herein, a bifunctional CF/MXene/FeS composite anode was fabricated through a one-step hydrothermal strategy to simultaneously enhance electricity generation and capacitive charge storage in MFCs. Unlike conventional bioanode modifications that primarily target conductivity enhancement alone, the constructed hierarchical composite integrates conductive MXene nanosheets and electroactive FeS phases to synergistically improve extracellular electron transfer and interfacial charge-storage behavior. The modified electrode exhibited enhanced surface roughness, abundant electroactive sites, and improved biofilm-supporting interfaces. Benefiting from the integrated conductive and electroactive composite framework, the CF/MXene/FeS anode achieved a maximum power density of 1.69 W/m², which was 70.7% higher than that of pristine CF, together with an increased open-circuit voltage of 0.711 V. In addition, the composite electrode delivered a high total charge density of 13,192.09 C/m² under the C900/D900 condition. Microbial community analysis further revealed substantial enrichment of electroactive bacteria, with the relative abundance of Geobacter increasing from 0.0058% to 22.84%. This work provides a promising strategy for integrating electricity generation and transient energy storage in bioelectrochemical systems, offering potential applications for energy-buffered MFCs under fluctuating power-demand conditions. Full article

In this work, monodisperse carbon microspheres with an average diameter of approximately 900 nm were successfully synthesized via a hydrothermal method. To further tailor their surface properties, the layer-by-layer (LbL) self-assembly technique was employed, where the cationic polyelectrolyte poly(diallyldimethylammonium chloride) (PDDA) and the anionic polyelectrolyte poly(styrene sulfonate) (PSS) were alternately deposited on the microsphere surface, forming two and four bilayer assemblies, respectively. The resulting composite microspheres exhibited remarkable adsorption performance toward representative dyes in water solution, such as rhodamine B (RhB) and methylene blue (MB). Experimental results demonstrated that the incorporation of a single bilayer significantly reduced the specific surface area but introduced additional active adsorption sites, thereby enhancing dye removal efficiency. However, when the number of bilayers was further increased to two, partial pore coverage and blockage occurred, leading to a reduced surface area and consequently diminished adsorption capacity. These findings highlight that in LbL surface modification, more layers do not necessarily yield better performance, but rather an optimal assembly thickness exists. This insight provides valuable guidance for the rational design of advanced adsorbent materials for wastewater treatment. Full article

Faced with a global energy crisis and ecological degradation, overall water splitting (OWS) is a pivotal approach for renewable energy conversion and storage. However, its industrial application is hindered by the high energy barriers/sluggish kinetics of the anodic oxygen evolution reaction (OER), as well as the scarcity of precious metal catalysts limiting large-scale deployment. Herein, a cobalt-based layered double hydroxide (Co-LDH) was used as the precursor, and a multi-strategy synergistic modification (hydrothermal synthesis, Fe doping, sulfurization, and external magnetic field magnetization) was applied to fabricate the Fe-Co₃S₄-MS-20 min electrocatalyst. This strategy establishes Fe-Co bimetallic synergistic active centers, and magnetic treatment modulates the electron configuration of Fe 3d orbitals without changing the material’s lattice spacing or morphology. Structural characterizations and electrochemical measurements were used to investigate the effects of combined modifications on the catalyst’s phase structure, morphology, electronic structure, and trifunctional catalytic performance toward the hydrogen evolution reaction (HER), OER, and urea oxidation reaction (UOR). The Fe-Co₃S₄-MS-20 min catalyst exhibits a larger electrochemical active surface area, lower charge transfer resistance, and smaller Tafel slope in 1 M KOH, it achieves overpotentials of 165 mV for HER (10 mA·cm⁻²) and 310 mV for OER (100 mA·cm⁻²), along with superior UOR performance and long-term stability. In situ impedance and Raman spectroscopy confirm that magnetization accelerates charge transfer and promotes in situ reconstruction. Synergistic multi-strategy regulation optimizes the electronic structure of active centers, reducing electrocatalytic energy barriers. This work provides new insights into designing high-performance non-precious metal electrocatalysts and offers experimental support for external magnetic field regulation in electrocatalyst modification. Full article

In this study, polyhedral self-assembled spherical titania (TS) photocatalyst was successfully synthesized via a one-step hydrothermal method from titanium chloride, sodium dodecyl sulfate and sulfuric acid. Titania modification with iron was carried out through the same procedure by the addition of different amounts of iron(III) chloride to the substrate mixture. Various methods were applied for sample characterization, e.g., XRD, SEM, TEM, XPS, UV-vis DRS, and photo-electrochemical measurements, such as EIS, CV, transient photocurrent, whereas photocatalytic activity was investigated for hydrogen evolution under UV/vis and oxidative decomposition of antibiotics under UV and/or vis, including also tests with scavengers. It has been found that iron was both incorporated in the titania structure (doping) and adsorbed on its surface. Although iron presence has hardly influenced the properties (slight changes in morphology, bandgap energy, and crystallite size), the photocatalytic activity has increased significantly. Therefore, it is proposed that iron might work as an electron sink, hindering the charge carriers’ recombination. Linear evolution of hydrogen, recycling experiments and characterization of samples after recycling have confirmed a good stability of iron-modified titania. Full article

In this work, Etna ash-derived photocatalysts were investigated for the first time for solar H₂ production. Volcanic ash, commonly treated as a special waste in eastern Sicily (Italy), was modified through chemical treatment followed by microwave-assisted crystallization, avoiding the conventional high-temperature thermal route. The obtained material was tested both as a bare photocatalyst and as a support for a Nb₂O₅/graphitic carbon nitride composite prepared by a hydrothermal method. The Etna-derived photocatalyst exhibited a solar H₂ production rate (by TEOA photoreforming) of 920 μmol/g_cat∙h. Upon incorporation of the Nb-based composite, the H₂ evolution rate increased by about 2.5 times, reaching 2370.5 μmol/gcat∙h, demonstrating a strong synergistic effect. Notably, the developed materials largely outperformed commercial TiO₂ P25 (25 μmol/g_cat∙h). The enhanced photocatalytic activity was attributed to the tailored modifications of Etna ash, which increased porosity and promoted aluminosilicate framework reorganization, favoring an optimal distribution of the photocatalytically active TiO₂ and iron oxide phases. The obtained Nb oxide/carbon nitride supported on modified Etna ash also showed a remarkable stability after six consecutive runs of solar photocatalytic H₂ production. This work demonstrates a sustainable strategy for converting volcanic waste into efficient multifunctional photocatalysts while minimizing the use of critical raw materials. Full article

The reasonable structural design and interfacial modification of heterojunction photocatalysts for accelerated charge separation and boosting photocatalytic activity remains a crucial challenge in solar-driven water splitting for H₂ production. Herein, a hierarchical structured In₂S₃/Ti₃C₂/TiO₂ ternary heterojunction was effectively constructed through a facile hydrothermal method integrated with a self-assembly strategy, in which Ti₃C₂ and TiO₂ were loaded on the surface of hierarchical In₂S₃ microspheres assembled from nanosheets. In the photocatalytic system, the in situ electron paramagnetic resonance verifies that the photogenerated charge transfer between In₂S₃ and TiO₂ obeys a typical S-scheme mechanism. Meanwhile, the introduction of Ti₃C₂ MXene as a conductive cocatalyst further promotes the separation and transfer of photogenerated charge through the formation of a Schottky junction, thus remarkably boosting the photocatalytic performance. Under simulated sunlight irradiation, the In₂S₃/Ti₃C₂/TiO₂ ternary heterojunction exhibits a superior H₂ production rate compared to pure TiO₂ and In₂S₃. Moreover, the ternary heterojunction also displays outstanding stability after five consecutive cycling tests. This work highlights the synergistic integration of an S-scheme and Schottky junction in a ternary heterostructure for efficient charge separation, providing a feasible strategy for designing high-performance photocatalysts toward solar-driven H₂ production. Full article

Bamboo is a renewable and fast-growing biomass resource with limited utilization and service life owing to its susceptibility to mold. Conventional nano-modification methods, particularly two-step approaches, are limited by weak interfacial bonding between nanoparticles and the bamboo substrate, complex processing, and an inability to simultaneously enhance antimildew performance and dimensional stability. To address these limitations, we developed a one-step hydrothermal method involving the use of tannic acid (TA) for in situ fabrication of ZnO/TA/Ag composite particles on bamboo surfaces. Process parameters were optimized to 100 °C, 10 h, and a zinc acetate-to-tannic acid molar ratio of 20:1. The modified bamboo was characterized using Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy coupled with energy-dispersive spectroscopy, and thermogravimetric analysis. We demonstrated that ZnO/TA/Ag composite particles were successfully loaded onto the bamboo surface, thus improving the all-around performance of the bamboo simultaneously. Antimildew activity against Aspergillus niger and Penicillium citrinum increased from grade 4 in untreated bamboo to grades 1 and 0, respectively; water absorption decreased by 52.85%, and anti-swelling efficiency reached 30.41%, indicating improved mold resistance and dimensional stability. Thus, our technique could serve as a green and efficient one-step in situ modification strategy for high-performance functionalization of bamboo, making it suitable for applications in humid outdoor and indoor environments. Full article

This study investigates the hydrothermal modification of commercial titanium dioxide (TiO₂) in the presence of a natural licorice root extract (Glycyrrhiza glabra L.), serving as a stabilizing and growth-modulating agent. The experimental framework combines hydrothermal treatment in a Teflon-lined autoclave with subsequent thermal calcination to elucidate the structural, morphological, and chemical evolution of the material. The plant-based extract significantly influences particle assembly during synthesis, fostering the formation of an initial organic–inorganic hybrid system that results in enhanced morphological homogeneity compared to pristine TiO₂. Thermal analyses (TGA and DSC) demonstrated the progressive decomposition of the organic components with increasing temperature, yielding a thermally stable, predominantly inorganic material at 600 °C. Scanning Electron Microscopy (SEM) observations confirmed a more uniform particle distribution in the modified samples. X-ray diffraction (XRD) patterns corroborated that the primary crystalline phase of TiO₂ remains intact across all conditions, with structural variations limited to peak definition and long-range organization. Furthermore, FTIR spectroscopy supported the preservation of characteristic TiO₂ vibrational features while indicating a gradual depletion of weakly bound surface species following thermal treatment. In conclusion, these findings demonstrate that natural extracts can effectively function as growth-modulating agents, steering material organization without altering its intrinsic chemical properties. This approach aligns with the principles of Green Chemistry and the circular economy, highlighting the potential of renewable plant-based resources as functional additives for the sustainable processing of inorganic materials. Rather than seeking to outperform commercial benchmarks, this work establishes a viable and low-environmental-impact strategy for morphological and structural modulation. Full article

To overcome the inherent limitations of 2D MXenes in photocatalysis, namely severe nanosheet restacking and rapid charge recombination, this study reports a synergistic dual-modification strategy. By integrating microwave-assisted in situ growth of carbon nanotubes (CNTs) with the hydrothermal incorporation of multivalent cobalt (Co) species, a 3D hierarchical Co-Ti₃C₂/CNT composite was successfully fabricated. Structural characterization reveals that the in situ grown CNTs act as robust spatial spacers and conductive highways, effectively preventing Ti₃C₂ agglomeration while providing a continuous electron-transfer network. The introduction of Co significantly enriches the surface with redox-active sites and facilitates the formation of an interfacial Schottky junction. Under visible-light irradiation, the optimized Co_10%-Ti₃C₂/CNT composite achieved a superior methylene blue degradation efficiency of 90.3% within 120 min. Mechanistic insights, supported by EPR and electrochemical analyses, confirm that the Schottky barrier at the semiconductor-metal interface acts as a potent electron trap, significantly suppressing e⁻/h⁺ recombination and accelerating surface-mediated radical generation (•OH, •O₂⁻). This work provides a sophisticated template for designing high-performance, dimensionally stable MXene-based heterostructures for advanced environmental remediation. Full article

Sustainable valorization of biomass through hydrothermal carbonization (HTC) represents an environmentally benign method for producing carbon materials for water treatment applications. This research aims to optimize the production of hydrochar from waste food by focusing on parameter optimization, physicochemical characterization, and the capacity of hydrochar to act as an adsorbent for the removal of the copper (II) ion from polluted water. A design of experiments using the RSM approach was employed to evaluate and optimize the influence of carbonization temperature, ranging from 180 to 250 °C, with a residence time of 2–5 h. The predictive ability of the MINITAB-generated model was close to accurate, as demonstrated by the design application for process simulation. The maximum % hydrochar yield was 72.65% for the experimental yield and 71.53% for the predicted yield, both obtained from a sample carbonized at 166 °C for 3.5 h. Batch adsorption experiments were conducted to assess the hydrochar’s ability to remove Cu²⁺ from aqueous solutions, and the Langmuir and the Freundlich isotherms were fitted at different pH levels. A comprehensive characterization of the produced hydrochar was conducted using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy (SEM-EDS). The results revealed significant modifications in surface morphology, pore development, and the presence of oxygen-containing functional groups. Based on the findings in this report, it is safe to conclude that hydrochar derived from food waste could serve as a potential adsorbent. Overall, the study demonstrates that sustainable hydrochar production from biomass can simultaneously address waste management challenges and provide an efficient solution for heavy metal removal, thereby advancing circular bioeconomy and environmental protection. Full article

Heavy oil and extra-heavy oil represent mobility-limited petroleum resources because supramolecular associations of asphaltenes and resins, together with strong interfacial resistance, generate extremely high apparent viscosity. In recent years, nanotechnology has emerged as a promising approach for viscosity management and enhanced oil recovery (EOR). This review critically examines recent advances in nano-assisted viscosity reduction from a reservoir-operational perspective and organizes the literature into two field-relevant categories: metal-based and non-metal nano-systems. Metal-based nanoparticles (NPs) mainly promote catalytic aquathermolysis and related bond-cleavage and hydrogen-transfer reactions under hydrothermal conditions, enabling partial upgrading and persistent viscosity reduction during thermal recovery. In contrast, non-metal nano-systems—particularly silica- and graphene-oxide-derived materials—primarily operate through interfacial and structural regulation mechanisms at low or moderate temperatures. These effects include wettability alteration, interfacial-film stabilization, modification of asphaltene aggregation behavior, and the formation of dispersed-flow regimes such as Pickering-type emulsions that reduce apparent flow resistance in multiphase systems. Beyond summarizing nanomaterial types, this review emphasizes reservoir-scale considerations governing field applicability, including brine stability, NPs transport and retention in porous media, and formulation compatibility. Comparative analysis highlights the distinct operational windows of thermal catalytic nano-systems and cold-production nano-systems, providing a reservoir-oriented framework for designing nano-assisted viscosity-reduction technologies. Full article

Neoproterozoic iron formations (NIFs), deposited during Cryogenian glaciation events, are critical for understanding early Earth oxidation events and the evolution of glacial–interglacial environments. Apatite, a common accessory mineral in iron formations, holds significant implications for sedimentary environments and diagenetic processes, but these aspects remain underexplored. This study focuses on the Hengyang NIF in the Nanhua Basin, South China. Using whole-rock geochemistry and major and trace element analysis of apatite, we investigate the environmental significance of apatite and associated diagenetic processes. Our results show that the Hengyang NIF are formed through the mixing of low-temperature hydrothermal fluids, seawater, and terrigenous detrital materials, with hydrothermal contributions increasing progressively from the bottom to the top of the iron formation layers. Whole-rock geochemical proxies indicate that the depositional water column evolved from relatively oxidizing to weakly oxidizing conditions. The study further demonstrates that the rare earth element patterns in apatite, characterized by middle rare earth element enrichment, are primarily controlled by porewater chemistry during diagenesis. In contrast, Ce anomalies and the V/Cr and V/(V + Ni) ratios in apatite, which are strongly influenced by fluid–rock interactions and magnetite recrystallization, no longer reliably reflect the primary depositional environment. The Th/U ratio in apatite, due to its geochemical stability, aligns with whole-rock trends and serves as a more reliable redox proxy. Based on these findings, we propose a three-stage depositional-diagenetic model: the early and late stages are characterized by high-energy, rapid sedimentation with minimal diagenetic modification, while the middle stage is dominated by low-energy, stagnant conditions with slow sedimentation rates, leading to prolonged diagenesis and significant decoupling of mineral geochemical signatures. This study emphasizes the need to distinguish between sedimentary and diagenetic signals when using mineral geochemical proxies to reconstruct paleoenvironments and provides new insights into the genesis of Neoproterozoic iron formations. Full article

Background: In this study, type B gelatin was extracted from Oreochromis niloticus scales under hydrothermal conditions at 60 °C to evaluate the effect of ultrasound-assisted pretreatment on its structural, physicochemical, thermal, and functional properties. Methods: Gelatin obtained with and without ultrasound pretreatment was systematically characterized through molecular weight analysis, proteomic profiling, size determination, surface morphology, proximate composition, thermal behavior, and gelation-related functional properties in order to assess the influence of the extraction method on gelation performance. Results: Ultrasound pretreatment slightly increased gelatin yield from 1.46 to 1.70%, indicating enhanced collagen solubilization. Proteomic analysis confirmed the predominance of fibrillar collagen proteins in both samples, although differences in protein distribution were observed. Furthermore, weight-average molecular weight analysis revealed a reduction from 212.3 ± 11.8 to 170.9 ± 13.2 kDa in the ultrasound-treated sample, suggesting partial fragmentation of collagen chains induced by cavitation effects. Structural modifications were also reflected in increased porosity and surface changes, contributing to improved colloidal stability. However, these changes significantly affect the functional behavior of the gelatin. Ultrasound-treated sample exhibited limited gel-forming capacity and failed to form stable gels at the evaluated concentration, despite complete dissolution. In contrast, gelatin extracted without ultrasound treatment retained higher-molecular-weight fractions and formed stable gels at both 5 and 10% (w/w). Thermal and spectroscopic analyses suggested that the fundamental collagen structure was preserved in both samples, although differences were observed in thermal degradation behavior. Conclusions: These results highlight the importance of controlling ultrasound-assisted extraction conditions to balance collagen recovery with the preservation of molecular integrity required for gelation, providing insights for the development of sustainable fish-derived biomaterials for pharmaceuticals and biomedical applications. Full article