Search Results (3,016)

Surface discharge-induced degradation poses a significant threat to the operational reliability of high-voltage insulation systems. This research investigates the dielectric endurance of polyester-based nanocomposites reinforced with seven distinct nano-additives: iron oxide (Fe₃O₄), copper oxide (CuO), titanium oxide (TiO₂), aluminum oxide (Al₂O₃), silicon dioxide (SiO₂), zinc borate (ZnB) and graphene oxide (GO). Specimens were fabricated at 0.5% and 0.75% weight concentrations and subjected to constant AC electrical stress of 4.5 kV at 50 Hz until failure using the first-plane tracking method. To accurately monitor the aging process, a sophisticated signal processing framework involving Hankel-matrix-enhanced Robust Principal Component Analysis (RPCA) was developed to extract high-frequency discharge features from captured leakage current signals. The degradation characteristics were quantified using various statistical metrics, including Kurtosis, RMS and Burst Discharge Index (BDI). Experimental findings demonstrate that the incorporation of nanoparticles significantly extends the time-to-failure compared to neat polyester, although the effectiveness is highly dependent on both additive type and concentration. At 0.5 wt.%, ZnB exhibited the superior performance in delaying carbonized track formation. However, at 0.75 wt.%, Al₂O₃ emerged as the most effective additive, achieving a maximum endurance time of 31.61 min. In contrast, certain additives like TiO₂ showed a performance decline at higher loadings, likely due to nanoparticle agglomeration. The Hankel-RPCA methodology successfully isolated discharge-specific signatures from background noise, establishing a strong correlation between signal features and material failure stages. This study confirms that the synergy between advanced nanomaterial modification and robust signal processing provides an effective diagnostic tool for monitoring insulation health, offering a vital pathway for the designing of high-performance dielectrics for real-world power system applications. Full article

Graphene and its derivatives are widely recognized as effective reinforcements due to their unique mechanical, thermal and lubrication performance. Incorporation of these reinforcements into polyamide-imide (PAI) coating matrix has shown significant potential for improving the tribological performance. Here, the mechanisms underlying the tribological improvement enabled by graphene oxide (GO) are investigated via frictional experiments and molecular dynamics simulations. It was found that the coefficient of friction (COF) of PAI coating is reduced upon the addition of GO over the range of 100–400 MPa and 20–100 mm/s, with a maximum reduction of ~25% achieved at 200 MPa and 60 mm/s. Simulations reveal that the friction reduction arises from strong adhesion interactions between the embedded GO sheets and PAI molecular chains, which inhibit the shear-induced mobility of the chains during the friction process. This mechanism enables a further reduction in the COF of the GO/PAI composite coating by increasing the interfacial adhesion through the tailored modulations of surface morphology and chemistry of the GO sheets. These findings pave the way for advancing the rational design and application of graphene-based composite coatings with highly improved tribological performance. Full article

Neuropsychiatric conditions constitute a major and growing global health burden, with prevalence rates that continue to rise worldwide. Although these disorders have traditionally been studied primarily from a neuronal perspective, accumulating evidence indicates that immune dysregulation and inflammatory processes play a central role in their pathophysiology. In this review, we advance the hypothesis that nitric oxide (NO)-mediated alterations in blood–brain barrier (BBB) integrity represent a critical mechanistic link between inflammation and central nervous system dysfunction in neuropsychiatric disorders. NO is a gaseous multifunctional signaling molecule involved in vascular homeostasis and immune responses, and its dysregulated production, together with aberrant protein S-nitrosylation, has been implicated in several neuropsychiatric conditions. However, the specific mechanisms by which NO signaling contributes to BBB dysfunction remain incompletely defined. Here, we synthesize current evidence supporting a role for NO-dependent vascular and inflammatory pathways in BBB disruption and discuss how these processes may contribute to the onset and progression of neuropsychiatric conditions. Clarifying these mechanisms may provide novel insights into disease pathogenesis and identify therapeutic targets aimed at preserving BBB integrity and limiting neuroinflammation. Full article

Artificial sweeteners have emerged as contaminants of increasing concern due to their widespread consumption, environmental persistence, and resistance to conventional wastewater treatment. This review provides an integrated assessment of global research trends and the environmental behavior of major artificial sweeteners, including sucralose, acesulfame potassium, saccharin, and aspartame. Bibliometric analysis of SCOPUS-indexed publications reveals rapid growth in research since 2010, with key themes focusing on environmental occurrence, treatment technologies, and ecotoxicological effects. These compounds are frequently detected in wastewater effluents, surface waters, groundwater, and even drinking water systems, driven by their high solubility and limited biodegradability. Their persistence raises concerns regarding ecological impacts, including potential alterations to microbial communities and aquatic organisms. In addition, emerging evidence suggests potential human health implications, including gut microbiota disruption, metabolic effects, and risks associated with chronic low-dose exposure, although these remain poorly understood. The performance of existing treatment technologies, including biological processes, adsorption, advanced oxidation, and membrane filtration, is critically evaluated, highlighting limitations in complete removal and in the formation of transformation products. Future research should prioritize sustainable treatment strategies, comprehensive risk assessment, and improved monitoring frameworks to better address both environmental and human health risks associated with artificial sweeteners. Full article

Arsenic contamination in groundwater is a severe and widespread environmental and public health challenge. Recent years have witnessed rapid advances in catalytic remediation technologies, particularly those integrating advanced oxidation processes (AOPs), bifunctional materials, and field-scale applications. This comprehensive review synthesizes recent developments, emphasizing the synergy between catalytic oxidation and adsorption, the design of innovative and recyclable materials, and the practical translation of laboratory findings to real-world remediation scenarios. Key breakthroughs include dual-function catalysts for combined contaminant removal, scalable systems compatible with renewable energy, and hybrid strategies integrating conventional and catalytic routes. Case studies from arsenic hotspots worldwide demonstrate not only technological feasibility but also highlight knowledge gaps and sustainability challenges. By evaluating catalytic mechanisms, operational performance, and environmental impact, this review identifies promising directions for the next generation of arsenic remediation and offers a critical roadmap to guide future research and practice. Full article

Synthetic dyes frequently persist through conventional wastewater treatment, motivating the use of advanced oxidation processes capable of breaking down these stable molecules. Metal-doped carbon dots (CDs) offer a tuneable platform for catalytic dye degradation in water, although their performance varies strongly with operating conditions. The aim of this work was to determine how temperature, H₂O₂ dosage, and pH influence the catalytic behaviour of Fe-, Cu-, Zn-, and Mg-doped CDs during the degradation of methylene blue (MB) and rhodamine B (RB), optimised using a Taguchi L27 orthogonal array design. Temperature and oxidant loading were the dominant factors: higher temperatures accelerated reactions through Arrhenius-type kinetics, while increasing H₂O₂ availability improved removal until excessive levels began to suppress •OH generation. Across all condition sets, apparent rate constants spanned 7.0 × 10⁻⁴–2.65 × 10⁻² min⁻¹, with t₅₀ values of 26–217 min and t₉₀ extending from ~86 min to >700 min; final decolourisation ranged from ~17% to nearly 100%. pH played a secondary role, mainly affecting dye speciation and surface adsorption. Dopant identity shifted the optimum operating region for each catalyst: Fe- and Cu-CDs achieved complete or near-complete removal of both dyes at pH 7 and 50 °C with relatively low H₂O₂ dosage (0.5–1.0 mL); Zn-CDs reached equivalent performance at pH 7 and 25 °C but required higher oxidant loading (1.5 mL of H₂O₂), reflecting their photo-induced rather than thermally driven activation mechanism; Mg-CDs performed comparably under the same conditions as Fe- and Cu-CDs. The resulting condition–catalyst map highlights the operating regimes that maximise efficiency while minimising chemical input, providing a practical framework for selecting carbon-dot-based catalysts for water treatment applications. Full article

Phase formation characteristics during the thermochemical reduction of metals from natural coltan using aluminum and calcium–aluminum alloy at 1400–1450 °C were investigated to develop methods for extracting niobium and tantalum from rare metal raw materials. The studied coltan sample consists of a columbite–tantalite solid solution with the composition (Mn,Fe)(Nb,Ta)₂O₆, cassiterite Sn_0.9O₂, tapiolite (Ta,Nb)₂(Mn,Fe)O₆, and calcioolivine Ca₂SiO₄. This study established that the choice of reducing agent determines the sequence of oxide phase transformations. During the aluminothermic process, orthorhombic columbite–tantalite is completely reduced, while tetragonal tapiolite persists even at 1400 °C. The use of a calcium–aluminum alloy containing 69.4 wt.% Ca results in a reversal of this trend: tapiolite is reduced at the early stages (800–1250 °C) through an intermediate (Ta,Nb)O₂ phase, whereas the columbite–tantalite solid solution remains up to 1250 °C. Calcium, having a high affinity for oxygen, forms intermediate perovskite-type oxide phases that act as diffusion barriers, limiting the access of the reducing agent to residual mineral inclusions (mainly Nb-Ta minerals of the orthorhombic crystal system). A temperature rise to 1450 °C initiates the redistribution of oxide components: the content of CaNbO₃ decreases, the Ca₂(Nb,Ta)AlO₆ phase disappears, and its components are involved in the formation of Ca(Nb,Ta)_0.25MnO_2.74 and Ca₄Nb₂O₉. Diffusion constraints are reduced, and the residual columbite–tantalite solid solution is reduced, as confirmed by its complete absence in the products at 1450 °C. In the metallic phase, solid solutions of tantalum and niobium, Ta-Nb-Sn intermetallic compounds (Ta,Nb)₃Sn, titanium aluminide, and ferroalloys with an increased (Ta,Nb)/(Fe,Mn) ratio are formed. The phase transformations elucidated during metallothermic reduction of coltan using different reducing agents, together with the formation of metallic and intermetallic phases, establish a scientific foundation for the development of advanced rare metal extraction processes. Full article

In recent decades, triazine herbicides (THs), one of the most widely used agrochemicals, have been extensively applied to enhance crop yields. However, their persistent nature and high mobility have resulted in pervasive contamination of aquatic ecosystems, posing significant risks to non-target organisms and human health through bioaccumulation and endocrine disruption. Addressing THs pollution in water bodies has thus emerged as a critical environmental challenge. This study reviews the efficacy of biochar, a carbon-rich material derived from biomass pyrolysis, for TH removal due to its high surface area, hierarchical porosity, and tunable surface functionality. The maximum reported adsorption capacities are up to 260.5 mg·g⁻¹; with degradation efficiencies, they can exceed 99.5% in advanced oxidation systems. Mechanistic investigations reveal that TH removal primarily involves π–π interactions, hydrogen bonding, pore filling, and electrostatic attraction during adsorption, while degradation proceeds via radical pathways (e.g., •OH, SO₄^•−) and nonradical routes (e.g., ¹O₂, direct electron transfer) in processes such as persulfate activation, photocatalysis, and Fenton-like reactions. By analyzing degradation intermediates and pathways, this review underscores the necessity of coupling adsorption with advanced oxidation to achieve complete mineralization and mitigate secondary ecological risks. Furthermore, it emphasizes the importance of tailoring biochar’s physicochemical properties through feedstock selection, pyrolysis conditions, and chemical modifications to optimize THs’ removal performance. This work advocates for the integration of biochar-based technologies into sustainable water treatment frameworks, aligning with carbon neutrality goals and circular economy principles. Future research should prioritize scalable synthesis methods, long-term stability assessments, and field-scale validations to translate laboratory insights into practical solutions for safeguarding global water resources. However, realizing this potential requires that we overcome challenges related to matrix interference, catalyst deactivation, and incomplete mineralization, which are often overlooked in laboratory-scale studies. Full article

Hydroxylamine-modified transition-metal oxides (HA-TMOs) represent a promising class of catalysts for activating peroxymonosulfate (PMS) to degrade antibiotics. However, identifying energy-efficient operational conditions remains challenging. This study established a comprehensive dataset encompassing 600 experimental records from both in-house experiments and literature and systematically compared 12 machine learning algorithms for predicting the antibiotic degradation efficiency (%) in hydroxylamine-modified transition metal oxide/peroxymonosulfate (HA-TMO/PMS) systems. Among these models, CatBoost delivered the best generalization (test-set R² = 0.8110, RMSE = 8.92, MAE = 6.15) across repeated 80/20 stratified splits with 5-fold cross-validation, outperforming other ensembles as confirmed by cumulative distribution plots and error-metric analyses. Moreover, the permutation importance analysis identified PMS dosage, HA level, pH, initial pollutant concentration, and catalyst loading as the dominant drivers governing the pollutant removal performance. The partial-dependence plots, incorporating two-variable interactions, elucidated the response surfaces and enabled the discovery of operating windows that jointly maximize degradation efficiency and minimize electrical energy per order (EE/O). ML-guided optimization yielded optimal conditions, which were experimentally verified with sulfamethoxazole (SMZ). The HA-Co₃O₄/PMS system achieved the highest degradation rate constant (k = 0.11 min⁻¹) and the lowest EE/O value (6.84 kWh·m⁻³·order⁻¹), markedly improving kinetics and reducing energy consumption compared with non-optimized runs. This work establishes an interpretable ML framework that connects catalyst properties and reaction conditions to degradation kinetics and mechanisms, providing a practical strategy for the screening and scale-up of energy-efficient HA-TMOs/PMS-based advanced oxidation processes (AOPs). Full article

The Lewis basic catalysts were susceptible to poisoning during the activation of peroxymonosulfate, resulting in their transformation into spent catalysts and subsequent secondary environmental contamination. In this work, the chemical constitution of the catalyst’s surface during both the deactivation and regeneration processes was intensively tracked. The mechanistic studies revealed that the reversible bonding of adsorbed hydroxyl groups generated from peroxymonosulfate activation with Lewis basic carbon atoms adjacent to pyridinic nitrogen was identified as the intrinsic mechanism responsible for the catalyst regeneration, accompanied by the reappearance of Lewis basic sites. Following high-temperature or sodium borohydride reduction, the activity of the catalysts was restored to over 90% of the initial activity, enabling the spent catalysts to be reused multiple times. Catalyst deactivation corresponded to an increase in the C–OH content from 24.3% to 35.2%, whereas regeneration reduced it to 25.16%. Furthermore, a strong inverse correlation was observed between the surface hydroxyl density and the catalytic activity. The study elucidates the deactivation and regeneration mechanisms of Lewis basic catalysts at the atomic scale, paving the way for durable applications in advanced oxidation processes. Full article

Textile wastewater remains one of the most challenging industrial effluents to remediate due to its intense and persistent coloration, high organic load, elevated salinity, and fluctuating pH and the presence of recalcitrant dye structures and auxiliary chemicals. Conventional physicochemical and biological treatments frequently achieve incomplete removal, generate secondary wastes, or fail under high-salt and toxic dye matrices. Advanced oxidation processes (AOPs) provide molecular-level degradation via reactive oxygen species (ROS), yet their deployment is often constrained by narrow operating windows, catalyst instability, chemical/energy demand, and scale-up limitations. In this context, metal–organic frameworks (MOFs) have emerged as tunable porous catalytic platforms that integrate adsorption and oxidation within a single architecture through controllable metal nodes, functional linkers, and engineered pore environments. This critical review reimagines textile effluent treatment through the lens of MOF-based hybrid catalysts, synthesizing progress across Fenton/photo-Fenton catalysis, photocatalytic MOFs, persulfate activation, and MOF-derived/composite systems. Mechanistic pathways are discussed by linking pollutant enrichment, cyclic redox reactions, charge-transfer processes, and ROS-driven degradation toward mineralization, with emphasis on the distinction between rapid decolorization and true organic removal. A critical comparison highlights how hybridization improves charge transport, stability, and catalyst recovery, while persistent gaps remain in hydrolytic robustness, metal leaching control, intermediate toxicity assessment, real-wastewater validation, continuous-flow reactor integration, and techno-economic feasibility. Finally, the review outlines actionable research directions, including water-stable and defect-engineered MOFs, immobilized and structured catalysts, solar-driven operation, standardized performance metrics, and life-cycle-informed design, to accelerate translation toward scalable and sustainable textile wastewater remediation. By bridging material chemistry with reactor-level feasibility and sustainability assessment, this review provides an implementation-oriented perspective for next-generation textile wastewater treatment. Full article

Hydrogen peroxide (H₂O₂) plays a vital role as an eco-friendly oxidizer, extensively used in environmental cleanup, energy transformation, and organic production. Nonetheless, the conventional method of creating anthraquinones is intricate, resulting in significant energy and ecological costs, which calls for the development of more eco-friendly and efficient substitute technologies. The article methodically examines the reaction processes and methods for improving efficiency in photocatalytic H₂O₂ generation in the past few years. This review summarizes the design principles and key structural features of various novel catalytic materials, focusing on light absorption, charge separation and migration, surface redox reactions, and enhanced mass transfer. Approaches such as expanding the range of bandgap absorption, building conjugated structures, and incorporating metal nanoclusters can significantly enhance the efficiency of light absorption. In the charge separation process, constructing built-in electric fields at the interfaces of heterojunctions, homojunctions, and Schottky junctions is crucial for improving reaction efficiency. Additionally, defect engineering may encourage targeted carrier movement and minimize recombination. The review highlights the latest advancements in enhancing selectivity and reducing H₂O₂ breakdown in surface redox reactions, achieved by regulating active sites, introducing new functional groups, and developing dual-channel reaction pathways. Furthermore, constructing three-phase interfaces, regulating asymmetric wettability, and designing cyclic/flow reactors provide innovative engineering solutions to address the challenges of insufficient oxygen supply and large-scale continuous production. Ultimately, the potential for producing H₂O₂ in photocatalytic systems is detailed. Full article

This paper systematically reviews the recent advances in catalytic systems and reaction mechanisms for the synthesis of crotonaldehyde via aldol condensation using acetaldehyde as the feedstock. Firstly, the structural characteristics, reactivity, and important applications of crotonaldehyde in fine chemicals are outlined, with particular emphasis on the limitations of traditional homogeneous base-catalyzed processes, such as difficulty in separation and environmental pollution caused by waste streams. On this basis, heterogeneous catalytic systems are discussed in detail, focusing on the progress of metal oxides, aluminosilicate zeolites, and heteroatom zeolites in regulating acid–base properties, active site structures, and reaction pathways. Furthermore, the typical carbanion mechanism and direct condensation mechanism in aldol condensation are summarized, and the catalyst deactivation and by-product formation mechanisms are analyzed. Finally, perspectives on the construction of efficient and green catalytic systems and future research directions are proposed, aiming to provide theoretical guidance for process optimization and catalyst design in crotonaldehyde synthesis from acetaldehyde. Full article

Diabetes mellitus affects an estimated 589 million adults globally, and cutaneous manifestations occur in up to 70% of affected individuals during the course of the disease. The objective of this narrative review is to examine the intersection of diabetes mellitus, skin aging, cosmetic dermatologic procedures, and regenerative therapies, with an emphasis on evidence-based best practices and clinical considerations. While the impaired wound healing associated with diabetes has been extensively studied, the aesthetic implications of diabetic skin disease remain comparatively underexplored. Individuals with diabetes frequently exhibit features of accelerated cutaneous aging, including premature wrinkling, dyschromia, xerosis, alopecia, and other cosmetically significant dermatoses that may negatively impact quality of life. In parallel, the demand for aesthetic dermatologic procedures among patients with diabetes has increased substantially; however, evidence-based recommendations guiding the safe and effective use of cosmetic interventions in this population remain limited. Diabetic skin demonstrates accelerated biological aging driven by complex pathophysiological mechanisms, including the accumulation of advanced glycation end products, chronic low-grade inflammation, oxidative stress, microvascular dysfunction, and neuropathy. These processes partially overlap with chronological aging and photoaging but are mechanistically distinct and may influence tissue repair, inflammatory responses, and the safety profile of commonly performed aesthetic procedures such as chemical peels, laser resurfacing, dermal fillers, neuromodulators, and microneedling. Emerging regenerative approaches, including platelet-rich plasma, platelet lysate, and mesenchymal stromal cell-derived products such as exosomes and secretomes, have attracted increasing attention as biologically targeted strategies for cutaneous rejuvenation. Nevertheless, clinical evidence specifically addressing aesthetic interventions in diabetic populations remains limited. A diabetes-informed approach to aesthetic dermatology that considers metabolic status, procedure selection, and post-procedural monitoring is therefore essential to optimize safety and therapeutic outcomes. Full article

The development of efficient, sustainable, and low-cost catalysts for wastewater treatment remains a major environmental challenge. In this work, Zn-doped CuO nanostructures were successfully synthesized via a green route using Aloysia citrodora leaf extract as a natural reducing and stabilizing agent. The structural and morphological properties of the prepared catalysts were systematically characterized by XRD, Raman spectroscopy, FTIR, SEM, and EDX analyses. The results revealed the formation of highly crystalline monoclinic CuO nanoparticles, whose defect density and surface properties were significantly modified by Zn incorporation. The catalytic performance of the synthesized materials was evaluated through the heterogeneous Fenton-like degradation of Rhodamine B in aqueous solution under dark conditions. The Zn-doped CuO catalyst exhibited outstanding degradation efficiency (~99.97%) within only 30 min, using a low catalyst dosage of 15 mg and a minimal H₂O₂ amount of 25 μL. The enhanced catalytic activity is attributed to the synergistic interaction between Zn-induced lattice defects and the Cu²⁺/Cu⁺ redox cycle, which promotes efficient H₂O₂ activation and •OH radical generation. Radical scavenging experiments confirmed the dominant role of hydroxyl radicals in the degradation process. Compared with previously reported CuO-based catalysts, the present system demonstrates superior performance in terms of reaction rate, oxidant consumption, and energy efficiency. These findings highlight the potential of Zn-doped CuO synthesized via green chemistry as a promising and sustainable catalyst for advanced wastewater treatment applications. Full article