Search Results (2,993)

The removal of ammonia nitrogen (NH₄⁺-N) using advanced oxidation processes (AOPs) has garnered increasing attention in wastewater purification. However, the application of the UV-activated persulfate (PS) system for treating NH₄⁺-N wastewater is limited by the low reaction rate between NH₄⁺-N and the reactive species (·OH and SO₄·⁻) generated in the system. In this study, common chloride ions (Cl⁻) were employed to enhance the removal of NH₄⁺-N in the UV/PS process; when the system conditions were pH = 7, [PS]₀ = 10mM, [Cl⁻]₀ = 35 mM, 30 mg/L NH₄⁺-N was completely degraded within 40 min. The total nitrogen removal rate was 75.50%, and the reaction rate constant increased from 0.0026 min⁻¹ to 0.0801 min⁻¹. The introduction of Cl⁻ led to the generation of reactive chlorine species (RCS) in the system that could efficiently oxidize NH₄⁺-N over a wide pH range (3–9), and the RCS, which efficiently oxidized NH₄⁺-N across a wide pH range (3–9). Quenching experiments confirmed that these RCS were gradually produced through the activation of Cl⁻ by ·OH and SO₄·⁻. The common anions present in water bodies had little impact on the degradation performance of NH₄⁺-N in the UV/PS/Cl⁻ system. Overall, the UV/PS/Cl⁻ system proposed in this study offers an effective approach for the efficient removal of NH₄⁺-N. Full article

Removing trace amounts of dissolved organic matter (DOM) has always been a significant issue in the field of environmental science and engineering. Herein, a UV-coupled O₃ micro-nano bubble (O₃-MNB) system was constructed, demonstrating superior efficiency in eliminating DOM compared to bulk O₃-MNB oxidation and direct UV photolysis. Various advanced analytical techniques, including in situ electron paramagnetic resonance, Fourier transform infrared spectroscopy and three-dimensional excitation–emission matrix, were employed to reveal the mechanism of the reaction process. Benefiting from the abundant interfacial area and enhanced mass transfer efficiency provided by the micro-nano bubbles, along with the simultaneous generation of reactive oxygen species such as •OH through UV activation, the UV/O₃-MNB system demonstrates excellent performance in removing DOM, and more than 90% of the mineralization rate was achieved after 1 h reaction. Furthermore, the findings were verified using both municipal water and natural surface water, and the proposed system also shows advantages in energy consumption compared to direct UV irradiation and conventional O₃ treatment, with an energy consumption of 25 kWh/mg dissolved organic carbon. This study innovatively integrates UV light with O₃-MNB technology, offering novel insights for advanced water purification and providing valuable references for practical engineering applications. Full article

This work investigates the feasibility of using thermographic techniques to identify the three possible states of a silicon-based coating on a carbon–silicon matrix (ISiComp). Experimental tests were therefore carried out on specimens prepared in three different conditions: uncoated, coated, and coated then oxidized. The study compares lock-in thermography and pulsed thermography using both a cooled mid-wave infrared (MWIR) camera and an uncooled long-wave infrared (LWIR) microbolometric camera. The main objective is to distinguish coated from uncoated conditions and oxidized from non-oxidized conditions, while recognizing that the coated and oxidized states cannot coexist simultaneously on the same specimen. The results show that thermographic techniques, when supported by appropriate post-processing, are promising for this purpose. In particular, the uncooled LWIR camera provided better results than the cooled MWIR camera, whereas the current approach did not allow a robust distinction between the pristine-coated and oxidized-coated states. At the same time, the study highlights limitations related to specimen size and to the additional treatments applied to reproduce the different surface states. Future work will address larger specimens and real components, together with the implementation of advanced AI-based classification algorithms to overcome the current limitations of the proposed approach. Full article

This research evaluated the efficacy of using two types of biochar (non-modified and acidified) from date palm residues (fronds, leaves, pits) as soil amendments for enhancing soil fertility and maize growth. These biochars were produced through slow pyrolysis under oxygen-limited conditions at 500 °C. Our innovative approach was to minimize gas emissions by converting smoke into liquid fertilizer (LS), which was expected to improve seed germination and early plant growth stages. To assess this aim, a completely randomized experiment was conducted under lab conditions, in which 10 maize seeds were placed on double filter papers in Petri dishes and then exposed to seven concentrations of LS (0.0, 0.01, 0.10, 1.0, 10 and 100%, using distilled water for dilution v/v). The LS contains nutrients and bioactive compounds that may enhance seed germination and early plant growth at low concentrations, whereas higher concentrations may cause phytotoxic effects. Results showed that liquefied smoke at 0.1% increased the absolute percentage of maize germination from 75% (control) to 100% and achieved the highest root length of 9.80 cm. Acidified biochars at 5% reduced soil pH from 8.87 to 8.12 and enhanced potassium availability to 87.93 mg kg⁻¹. Conversely, the non-modified biochars contributed to further increases in soil organic matter (up to 1.02%), nitrogen, and phosphorus. In addition, the application of acidified leaf biochar (5%) enhanced maize shoot growth by 133%, chlorophyll content by 39%, and potassium uptake by 110%. This research establishes a scalable approach for converting agricultural waste into climate-resilient resources, effectively addressing soil degradation in arid environments, boosting crop resilience, and furthering the objectives of a circular bioeconomy. Full article

An integrated Visible–Near-Infrared to Shortwave Infrared spectroscopy (VNIR–SWIR spectral), mineralogical, and geochemical study was conducted on the Shadan Au–Cu porphyry–epithermal system in the eastern Lut Block, Iran, to characterize hydrothermal alteration zonation and classify alteration–lithological units. Thirty-eight representative samples were analyzed by reflectance spectroscopy (0.35–2.50 µm), petrography, XRD (X-ray Diffraction), X-ray fluorescence (XRF), and Inductively Coupled Plasma Mass Spectrometry (ICP–MS). Quantitative continuum-removal processing identified diagnostic absorption features near 0.90, 1.40, 1.90, 2.17, 2.20, 2.33, and 2.50 µm, corresponding to Fe³⁺, Al–OH, H₂O, and CO₃ absorptions. Seven alteration–lithological groups (G₁–G₇) were defined and verified by XRD and petrography, representing illite–smectic–kaolinite (argillic), alunite–dickite (advanced argillic), quartz–silicified, Fe-oxide, oxidized argillic, chlorite–epidote (propylitic), and carbonate–iron vein assemblages. Whole-rock geochemical data reveal coherent enrichments of Al₂O₃–K₂O in clay-dominant zones, Fe₂O₃ in oxide-rich areas, and CaO–MgO in carbonate-bearing assemblages. Spectral and geochemical integration delineates a vertically and laterally zoned system evolving from acidic to neutral–oxidizing conditions, typical of low-sulfidation epithermal overprints on porphyry-style magmatic centers. This multidisciplinary framework demonstrates the value of combining VNIR–SWIR spectroscopy with mineralogical and geochemical constraints for vectoring and classification of alteration systems in post-collisional volcanic belts. Full article

Microplastics and nanoplastics (MNPs), as emerging contaminants, have garnered growing interest for their persistence and biological toxicity. Wastewater treatment plants (WWTPs) are significant convergence points for MNPs, where they undergo complex aging, particularly during advanced oxidation processes (AOPs), leading to different environmental fate and behavior. This study aims to discuss the aging of MNPs in wastewater treatment induced by AOPs and evaluate their biological risks. This review was conducted in accordance with the 2020 PRISMA guidelines. We searched three electronic databases—Scopus, Science Direct, and Web of Science—for relevant articles published between the year 2000 and March 2026. A total of 39 studies met the inclusion criteria and a narrative synthesis was conducted to summarize the findings. Risk of bias assessment was not performed, as this is a narrative systematic review without quantitative synthesis. The review protocol was registered in the OSF (registration DOI: 10.17605/OSF.IO/FTQHN). First, aging pathways and the alterations in the physicochemical properties of MNPs caused by aging are summarized, mainly including changes in surface morphology, crystallinity, and chemical composition, etc. Second, the aging mechanism of MNPs and the factors affecting the aging were discussed. Third, the biotoxicity of aged MNPs on both microorganisms and humans was reviewed, which is mainly due to three sources: plastic particles themselves, released chemicals, and the combination of plastics with coexisting pollutants. Furthermore, this review also criticized the limitations in current studies, the lack of comprehensive evaluation of multiple environmental factors and the identification of specific toxicity; it also provides suggestions for future research. This overview is meaningful for better understanding the environmental fate and risks of MNPs. Full article

Ceramic materials are indispensable to aerospace and defence technologies, where structural and functional components are required to withstand extreme thermal, mechanical, and chemically aggressive environments. Traditionally valued for their exceptional thermal stability, oxidation resistance, and corrosion resistance, ceramics have nonetheless been constrained by their inherent brittleness, which has limited their widespread adoption in load-bearing structural applications. This review surveys the principal tough ceramic systems currently employed in aerospace and defence, including SiC, Al₂O₃, ZrO₂, Si₃N₄, SiC/SiC composites, and ultra-high-temperature ceramics (UHTCs) such as ZrB₂ and HfB₂. In parallel, it outlines advanced processing and manufacturing routes that enable enhanced microstructural control, improved reliability, and scalability for industrial deployment. Special attention is devoted to thermal and environmental barrier coatings (TBCs and EBCs), which provide critical protection against oxidation, corrosion, and severe thermal cycling in propulsion, power-generation, and hypersonic systems. Finally, the review highlights key material selection criteria for aerospace and defence platforms and discusses emerging trends that integrate tough ceramics with next-generation manufacturing technologies, underscoring their pivotal role in enabling high-performance, durable, and resilient systems for future extreme-environment applications. Full article

Insomnia is the most prevalent sleep disorder worldwide, affecting up to 30% of the population, and is frequently accompanied by cognitive complaints and measurable cognitive impairments. Chronic insomnia is characterized by persistent hyperarousal across physiological, cognitive, and neurobiological domains, which may compromise multiple cognitive systems. This review synthesizes current evidence on the impact of insomnia on major cognitive domains, including attention, language, memory and learning, executive functions, perceptual–motor skills, and social cognition. We critically evaluate methodological factors contributing to heterogeneous findings across studies, such as variability in diagnostic criteria, insomnia phenotypes, cognitive assessments, and sample characteristics. Additionally, we summarize emerging evidence on neuroanatomical and molecular correlates of insomnia-related cognitive impairment, including alterations in hippocampal and prefrontal brain structures, amyloid-β accumulation, dysregulation of brain-derived neurotrophic factor, neurotransmitter imbalance, neuroinflammation, and disrupted signaling pathways. Insights from preclinical studies show mechanistic links between sleep loss, synaptic dysfunction, oxidative stress, and memory decline. Despite substantial advances, the precise pathophysiological mechanisms underlying cognitive dysfunction in insomnia remain incompletely understood, suggesting that cognitive impairment arises from the convergence of multiple biological processes rather than a single causal pathway. A deeper mechanistic understanding is essential for developing targeted interventions for preventing cognitive decline in individuals with insomnia. Full article

Methane, as an abundant and relatively clean resource, has primarily been converted into various chemical products via indirect conversion through synthesis gas, a mixture of CO and H₂. Recently, interest in direct methane conversion technologies with lower energy consumption has increased. Compared to research on methanol production via selective oxidation of methane, studies on the direct conversion of methane to acetic acid have been relatively scarce, but significant research progress has been made recently. This review classifies reports on the direct conversion of methane into acetic acid according to catalyst type (homogeneous vs. heterogeneous catalysts) and reaction conditions, and discusses the advantages and disadvantages of each approach. A relatively high yield of acetic acid can be achieved using CO as a carbonylating agent. However, the direct conversion of methane and CO₂ into acetic acid is more attractive from an environmental perspective. Recent advances in the field of electrocatalysis for this purpose are noteworthy. Other non-thermal catalytic methods, including photocatalysis, photoelectrocatalysis, and plasma processes, are also included. Based on the current state-of-the-art research trends in this field, future research directions are proposed. Full article

Nitrate pollution in freshwater has become an increasing concern for both environmental sustainability and human health, especially in water reuse systems and intensive aquaculture. Photocatalytic reduction in nitrate to nitrogen gas (N₂) represents a promising low-chemical treatment strategy that can operate under sunlight or LED irradiation, and in general, enable nitrate removal without generating concentrated waste streams. Over the past decade, the development of advanced photocatalytic materials, including heterojunction semiconductors, plasmonic catalysts, and single-atom co-catalysts, has significantly enhanced visible-light absorption and overall photocatalytic performance. Despite these advances in photocatalyst design and synthesis, several critical challenges still limit the large-scale implementation of photocatalytic nitrate reduction to N₂. First, selectivity toward N₂ remains limited, as competing reaction pathways often lead to the formation of undesirable byproducts, such as nitrite (NO₂⁻), ammonium (NH₄⁺), and nitrous oxide (N₂O). Second, nitrogen reaction pathways are often uncertain, because many studies lack isotopic labeling or nitrogen mass balances, making it difficult to verify that the detected N₂ originates from nitrate reduction. Third, practical implementation is restricted by several technical challenges, including catalyst fouling or leaching, limitations in reactor design, excessive addition of hole scavengers, and the relatively high energy demand associated with indoor LED-driven systems. This review critically surveys advances from 2015 to 2025 in photocatalytic materials and reaction mechanisms for nitrate conversion to N₂. It highlights best practices for reliable product quantification and reaction pathway validation, and evaluates the feasibility of integrating these systems into recirculating aquaculture systems (RAS), where effective nitrate management is essential. In addition, the potential role of modern inline nitrate sensors (optical and electrochemical) and automated process control is discussed, outlining pathways toward hybrid photocatalytic–biological nitrate removal systems for sustainable aquaculture applications. Full article

Emerging pharmaceutical contaminants, including sulfonamide antibiotics such as sulfamethoxazole (SMX), persist in natural water bodies at ng L⁻¹ to µg L⁻¹ concentrations and are inadequately removed by conventional wastewater treatment technologies, posing significant ecological and public health risks. Porphyrin-based quantum catalysts activated by peroxymonosulfate (PMS) represent a promising advanced oxidation strategy for the remediation of such recalcitrant micro-pollutants. However, the precise molecular mechanisms governing their catalytic activity remain incompletely understood. In this study, we present a comprehensive mechanistic investigation of SMX oxidation catalyzed by Mn (III) meso-tetraphenylporphyrin (Mn-TPP) in the presence of PMS, employing spin-unrestricted density functional theory (DFT) at the Becke, 3-parameter, Lee–Yang–Parr (B3LYP-D3BJ) level of theory with dispersion corrections. Full Gibbs free energy profiles for the catalytic cycle were constructed through geometry optimizations using the LACVP basis set on Mn and 6-31G(d,p) on all non-metal atoms, followed by single-point energy calculation at the 6-311+G(d,p) level, incorporating the SMD implicit solvation model to stimulate aqueous environment conditions. The results demonstrate that the oxidation of Mn TPP by PMS to generate the key high-valent intermediate Mn(V)=O(TPP)⁺ is thermodynamically and kinetically favorable. The activation barrier for Mn(V)=O(TPP)⁺ formation via PMS activation is ΔG† = 17.2 kcal mol⁻¹ (SMD water, 298 K), confirming that this step is kinetically accessible under ambient environmental conditions. Subsequent SMX oxidation processes proceed via concerted radical and non-radical mechanistic pathways, with the most thermodynamically favorable route exhibiting a strongly exergonic reaction-free energy (ΔGr), indicating that significant mineralization of the target pollutant is thermodynamically accessible. The transition state analysis reveals spin density localization characteristic of the Mn-Oxo species, establishing a direct correlation between quantum confinement effects, electronic structure and the observed catalytic selectivity and oxidation stability of the Mn-TPP system. These mechanistic insights provide quantitative molecular-level design parameters, including activation barriers, spin state requirements, and electronic structure descriptors for the rational optimization of next-generation porphyrin-based quantum catalysts capable of efficiently degrading persistent pharmaceutical contaminants in complex aqueous matrices. Full article

In this study, sodium persulfate was used to oxidize Reactive Black 5 (RB5), an azo dye commonly used in the textile industry, and Reactive Blue 4 (RB4), an anthraquinone dye. Persulfate was activated using Fe(II) and natural solar irradiation to generate sulfate radicals (SO₄^•−), which possess a high redox potential and effectively oxidize organic pollutants in wastewater. Batch experiments demonstrated that the combined use of Fe(II) and solar-activated persulfate achieves up to 99% dye removal. The influence of natural solar irradiation was evaluated under outdoor conditions for both dye solutions, confirming the effectiveness of solar-activated persulfate oxidation. Mineralization was monitored via total organic carbon (TOC) analysis, with up to 97% dissolved organic carbon removal observed at the highest persulfate dosage for RB5. Two activation pathways were examined, and the results indicate that solar activation is a sustainable approach to minimizing energy and chemical consumption. This study also demonstrates the solar activation potential of the Lefke region in Northern Cyprus for advanced oxidation processes. Full article

Chelating agents can extend the operational pH range of iron-based advanced oxidation processes, yet comprehensive studies on chelated Fe-activated persulfate systems for textile dye degradation remain scarce. This study establishes an integrated framework for optimizing Fe(II)/persulfate (PS) systems using chelating ligands and hybrid energy inputs under near-neutral conditions. Among the tested systems, Fe(II)/PS complexed with citric acid (CA) exhibited superior performance, achieving ~91% dye removal within 20 min at pH 6.5 under optimized conditions (1.25 mM Fe(II), 10 mM PS, 0.1 mM CA). Chelation stabilized Fe redox cycling and prevented precipitation, enabling effective catalysis across pH 3–10. Optimal CA/Fe and Fe/PS ratios (0.1:1.25 and 1.25:10) yielded ~96% decolorization and 67.65% TOC removal in 60 min, while excessive chelation reduced activity. Transition metal screening (Mn(II), Zn(II), Cu(II), Co(II), and Ni(II) confirmed Fe(II) as the most effective activator, providing removal efficiencies up to 3.2-fold higher than competing metals. Mixed-dye experiments showed competitive degradation, with >37% color removal after 60 min for ternary dye mixtures. Mineralization reached ~92% TOC reduction after 120 min, indicating deep oxidation beyond chromophore cleavage. Reactive species quenching revealed a mixed oxidation mechanism involving ^•OH radicals and high-valent Fe(IV) species. Hybrid assistance improved mineralization, with UVC increasing TOC removal by 15.6%, while solar irradiation provided moderate enhancement under low-energy input. In contrast, low-power ultrasound (40 kHz, 60 W) delivered only 17.6 W acoustic power to the solution and did not improve performance due to limited cavitation and mixing. This work thus contributes a robust platform for advancing chelated iron-persulfate oxidation systems toward practical, effective treatment of recalcitrant dye-contaminated wastewaters under near-neutral conditions. Full article

Naturally Occurring Radioactive Materials (NORMs) in industrial wastewater present significant environmental and public health challenges due to their persistence and radiotoxic effects. This comprehensive review analyzes 108 peer-reviewed publications from 2014 to 2025 on NORM treatment technologies for industrial wastewater. While previous reviews have focused on individual treatment methods or laboratory-scale studies, this work provides comparative performance analysis across multiple technologies under realistic industrial conditions, including high-salinity environments and competing ions. We emphasize membrane filtration, electrocoagulation (EC), ion exchange, and advanced oxidation processes, evaluating both their economic feasibility and environmental sustainability for practical industrial implementation. The review discusses the advantages and limitations of existing techniques, highlighting the need for integrated strategies that combine physical, chemical, and biological processes for enhanced remediation. Hybrid systems combining multiple technologies outperform individual approaches by 15–25% in removal efficiency. These advances are critical for ensuring safe water reuse and protecting water resources from radioactive contamination. Additionally, regulatory frameworks governing NORM management are examined, underscoring the importance of standardized disposal and treatment protocols. The review concludes by identifying research gaps and future directions. Priority areas include developing standardized treatment protocols and strengthening academia–industry collaboration to achieve scalable solutions aligned with UN Sustainable Development Goal 6. Full article