Search Results (748)

The massive discharge of methylene blue causes severe water pollution, and the development of efficient and stable heterogeneous Fenton catalysts is crucial for wastewater treatment. To address the shortcomings of traditional iron-based amorphous catalysts, such as low activity and poor stability, this study employed Fe₈₀Si₆B₁₀Cu₁Nb₃ five-component amorphous alloy as the catalyst to investigate its catalytic degradation performance, cyclic stability, and catalytic mechanism for MB. Batch experiments, SEM, XRD characterization, and kinetic fitting were combined to carry out the research. The results showed that under the optimal conditions (25 °C, pH = 3, H₂O₂ concentration of 5 mM, catalyst dosage of 0.5 g/L), the catalyst could completely degrade methylene blue within 9 min with a reaction rate constant k_obs of 0.44 min⁻¹, and the degradation efficiency showed no obvious attenuation after 20 consecutive cyclic degradation runs. After degradation, slight selective corrosion occurred on the catalyst surface, while the amorphous structure of the matrix remained stable. This study confirms that the Cu/Nb dual synergy improves the catalytic performance and stability, clarifies the relevant catalytic mechanism, and provides theoretical and technical support for the design of high-performance iron-based amorphous catalysts and the treatment of dye-containing wastewater. Full article

High-frequency immersed plasma discharge represents an efficient method for the generation of reactive oxygen and nitrogen species (RONS) in liquid media, leading to complex redox and oxidative processes in biologically relevant systems. Although plasma-generated reactive species in liquids have been widely investigated, it remains insufficiently understood how working-gas-dependent plasma chemistry translates into oxidative outcomes in iron-containing model systems, where plasma-derived species may interact with transition-metal redox cycling. The novelty of this study lies in the combined assessment of gas-dependent RONS accumulation, deoxyribose oxidative degradation, and plasma-induced changes in Fe(II) availability using a high-frequency immersed plasma discharge. Herein, we examined whether treatment with high-frequency immersed discharge influences the redox state of iron in a working gas-dependent manner, thereby affecting oxidative degradation in the deoxyribose model. Plasma treatment was performed under air and argon working gas conditions, and oxidative degradation was evaluated using the thiobarbituric acid reactive substances (TBA-RS) assay. In parallel, the concentrations of long-lived reactive species, including hydrogen peroxide, nitrites, and nitrates, were determined spectrophotometrically. The results demonstrated a treatment-time-dependent increase in oxidative degradation and reactive species accumulation, with more pronounced oxidative effects observed under argon plasma conditions. In the presence of ferrous ions, plasma treatment resulted in a gas-dependent effect, characterized by a synergistic enhancement of oxidative degradation under argon and a biphasic effect under air. Most notably, in Fe(II)-containing samples, 10 min of argon plasma treatment increased TBA-RS formation to approximately 2.7-fold of the Fe(II) control, whereas air plasma produced a biphasic response, with an initial decrease followed by an approximately 40% increase at the longest exposure time. Additional experiments suggest that plasma may influence the redox state and availability of ferrous ions, thereby affecting their participation in Fenton-type reactions and radical-mediated processes. The findings suggest that the overall oxidative outcome in plasma-treated systems is governed not only by the concentration of plasma-generated reactive species but also by plasma-induced modifications of transition metal redox chemistry. These preliminary results on the combined roles of plasma-generated reactive species and transition-metal chemistry contribute to understanding plasma–liquid interactions in such systems. Full article

A Fe₃O₄/HNTs composite was synthesized, characterized by SEM, TEM, XPS, adsorption–desorption N₂, XRD, FTIR, VSM and Zeta potential, and was used for an ibuprofen adsorption and Fenton oxidation study. The response surface methodology (RSM) and Box–Behnken experimental designs were employed. The effects of pH, contact time, ibuprofen concentration, and Fe₃O₄/HNTs dosage on ibuprofen adsorption were evaluated. Additionally, adsorption isotherms and a kinetic study were performed. The effects of pH, H₂O₂ concentration, and Fe₃O₄/HNTs dosage for IBU removal were also studied. The results of ibuprofen adsorption on Fe₃O₄/HNTs indicate that adsorption was favored at acidic pH. The adsorption followed pseudo-second-order kinetics and a Freundlich isotherm. Under mild conditions (pH 7, 298.15 K) with a Fe₃O₄/HNTs dosage of 1.5 g L⁻¹ and 0.5 M H₂O₂, the heterogeneous Fenton-like reaction achieved 99% ibuprofen removal and 60% mineralization. The Fe₃O₄/HNTs catalyst demonstrated high efficiency for aqueous ibuprofen removal under environmentally mild pH and temperature conditions, and it was easily recoverable and reusable. Full article

In the process of pollutant degradation by activating peroxymonosulfate (PMS) with carbon-based Fenton-like catalysts containing Fe as the active site, the influence of Zn atoms on the system has rarely been studied. In this study, by regulating the introduction of Zn sources, Fe-Zn-C and Fe-C catalysts were successfully synthesized for activating PMS to degrade butyl xanthate (BX). The degradation experiment results showed that compared to the Fe-C system, the doping of Zn increased the degradation rate of BX in the Fe-Zn-C system by 10.66%, reaching 91.19% within 120 min. Moreover, by optimizing the reaction conditions, the highest BX degradation efficiency of 96.54% was achieved within 30 min. Through instrumental analysis, Fe and Zn elements were found to exist on the surface of the catalysts in the form of Fe²⁺Fe³⁺₂O₄ and ZnO crystals, and the catalytic oxidation reaction was dominated by non-free radical pathways, including ¹O₂ and direct electron transfer pathways. No free radicals were produced during the reaction, and it was speculated that Zn atoms played the role of an electron bridge in the reaction system, mediating electron transfer and enhancing catalytic performance through their synergistic effect with Fe. Comprehensive stability evaluation indicated that Fe-Zn-C ensures continuous catalytic activity and ecological safety with a low dissolution rate in aqueous solution. This study provides a new approach for the design of Fenton-like catalysts and the induction of non-radical pathways. Full article

¹O₂ has significant advantages over free radicals in Fenton-like reactions, but the induction of a single ¹O₂ reaction pathway is challenging and is often accompanied by free radical reactions and direct electron transfer pathways. In this study, Zn-O-C/N and Zn-S/O-C/N catalysts were synthesized by controlling the doping of the S element, and the single ¹O₂ reaction pathway was successfully induced. Furthermore, Zn-O-C/N performed better than the Zn-S/O-C/N system, with higher phenanthrene (PHE) degradation rates of 76.14% compared to 62.86%. And Zn-O-C/N can achieve a maximum degradation rate of 85.62% under the developed optimization condition. The characterization results revealed that the ZnO active sites are located on the surface of the Zn-O-C/N catalyst and participate in electron mediation together with C-N. ZnS was generated with the doping of S, speculating that a large amount of ZnS with low catalytic activity is generated and occupies the active sites, thereby inhibiting the catalytic activity. Additionally, only ¹O₂ was generated in the two systems, without the formation of free radicals and the occurrence of direct electron transfer reaction. However, the Zn-O-C/N catalyst has been proven to have strong stability and a low amount of dissolution, demonstrating environmental safety. This study confirmed the inhibitory effect of S on the activity of the Zn-O-C/N system and provided a synthesis strategy for the catalyst design, which can only induce the ¹O₂ reaction pathway. Full article

The pulping and paper-making (P&P) industry is one of the world’s largest manufacturing sectors, yet it is plagued by high water/energy consumption and massive discharge of highly polluted wastewater. The effluents from pulping, bleaching and papermaking processes are characterized by high chemical oxygen demand (COD), intense color, toxic adsorbable organohalides (AOX) and abundant refractory lignin, which pose significant threats to aquatic ecology and human health. Although conventional physical, chemical and biological treatments have been widely applied, they are constrained by insufficient degradation efficiency toward recalcitrant organics, high cost and potential secondary pollution. In recent years, electrocatalytic technologies including electrocatalytic oxidation, electroreduction and their integrated processes, have demonstrated superior efficacy in specific scenarios of P&P wastewater treatment, such as lignin degradation, toxic side-streams treatment, pretreatment for enhancing biodegradability, and polishing steps in integrated treatment systems, which are not universally applicable solutions for P&P wastewater remediation. Meanwhile, biomass fuel cells typified by direct biomass fuel cells (DBFC) and microbial fuel cells (MFC) provide promising pathways for synchronous pollutant removal, energy production and resource recovery. Representative studies have reported COD removal efficiencies of 60–100% for electrochemical and advanced oxidation processes, while integrated electro-Fenton–biological treatment increased the BOD/COD ratio from 0.34 to 0.52 and achieved an overall COD removal of 94%. It should be noted that these advanced electrochemical technologies are still confronted with challenges in industrial scale-up, high energy and electrode material costs, and stable continuous operation. This review systematically elaborates on the physicochemical properties, generation mechanisms and environmental impacts of P&P wastewater, comprehensively summarizes the mainstream treatment technologies including physicochemical, biological, electrochemical and integrated processes, and analyzes their reaction mechanisms, efficiencies and applicable conditions. Particular emphasis is placed on electrocatalytic treatment and bio-electrochemical valorization strategies. This review is anticipated to provide a valuable reference for the efficient and targeted treatment as well as sustainable utilization of P&P wastewater, thereby supporting the green and low-carbon development of the P&P industry. Full article

The resurrection plant Haberlea rhodopensis is a rare species endemic to Greece and Bulgaria, renowned for its exceptional desiccation tolerance and rich phytochemical composition. This study investigated the antioxidant, cytoprotective, and wound-healing-associated effects of H. rhodopensis ethanolic extract (HEE) in human keratinocytes (HaCaT cells) under oxidative and cytotoxic stress conditions. Antioxidant capacity was initially evaluated using a plasmid DNA protection assay, in which HEE attenuated oxidative DNA damage induced by a Fenton reaction system and preserved the native supercoiled structure of pUC19 plasmid DNA. Cytotoxicity screening using the sulforhodamine B (SRB) assay and real-time proliferation monitoring (HoloMonitor^® M4) identified 20 μg/mL as a non-toxic pre-treatment concentration (EC₁₀). Under hydrogen peroxide (H₂O₂)-induced oxidative stress, HEE pre-treatment maintained cell viability and significantly reduced intracellular reactive oxygen species (ROS) levels, indicating a protective effect. In vitro wound-healing assays demonstrated enhanced scratch closure in keratinocyte monolayers. RT-qPCR analysis revealed modulation of antioxidant-related genes (CAT, SOD1, HMOX1, NQO1, GPX, GSR), while mRNA sequencing suggested selective stress-adaptive responses, involving extracellular matrix (ECM)-, metabolic-, and tissue-repair/aging-associated pathways. Overall, HEE exhibits antioxidant and cytoprotective effects in keratinocytes and is associated with transcriptional changes linked to cellular stress responses and wound closure. These findings support its potential relevance for dermatological, pharmaceutical, and cosmeceutical applications, while further studies are required to establish the underlying molecular mechanisms. Full article

The Fenton reaction remains one of the most widely investigated advanced oxidation processes for wastewater treatment due to its ability to generate highly reactive oxygen species capable of degrading persistent organic pollutants. However, classical homogeneous Fenton systems suffer from significant limitations, including narrow pH applicability, iron sludge generation, and poor catalyst reusability. In response, extensive research has focused on the development of heterogeneous and advanced Fenton-like catalysts aimed at overcoming these challenges while enhancing catalytic efficiency and operational stability. This review provides a comprehensive and critical analysis of the evolution of Fenton catalysis, from classical homogeneous systems to advanced materials, including nanostructured catalysts, carbon-based Fe–N–C systems, metal–organic frameworks, and single-atom catalysts. A unified evaluation framework is proposed, integrating key performance parameters such as catalytic activity, manufacturability, stability, and catalyst lifespan. Comparative analysis reveals that improvements in activity are often accompanied by trade-offs in cost and scalability, indicating that the most advanced materials do not necessarily provide the best practical performance. A life cycle-oriented perspective is incorporated, emphasizing catalyst reuse, lifespan, and iron leaching, and providing quantitative insight into cumulative catalytic performance. The results demonstrate that long-term efficiency is governed not only by intrinsic activity but also by durability and operational stability under realistic conditions. Finally, current challenges and future directions are discussed, including scalable synthesis, improved mechanistic understanding, and integration into hybrid treatment systems. This review bridges the gap between fundamental research and practical application by highlighting the importance of balancing performance, stability, and sustainability in the design of next-generation Fenton catalysts. Full article

Iron overload significantly contributes to chronic kidney disease progression by triggering oxidative stress and mitochondrial impairment via the Fenton reaction. This study investigates the protective role of aldehyde dehydrogenase 1a3 (ALDH1a3), an enzyme that detoxifies reactive aldehydes, in renal iron overload. C57BL/6N mice were fed a 2.25% ferric citrate diet for 24 weeks to establish a chronic model, followed by treatment with the chelator Dimercaprol (DP). In vitro, TCMK−1 cells were subjected to iron intervention with ALDH1a3 overexpression or inhibition. Chronic iron overload induced significant renal iron deposition, lipid peroxidation (elevated MDA, depleted GSH), and mitochondrial structural damage. ALDH1a3 was endogenously upregulated in renal tubular epithelial cells under iron stress. Overexpressing ALDH1a3 significantly enhanced cell viability, suppressed reactive oxygen species and MDA levels, and preserved mitochondrial membrane potential, whereas its inhibition exacerbated cellular damage. Furthermore, DP treatment reduced iron deposition and was associated with increased ALDH1a3 expression. In conclusion, ALDH1a3 acts as a critical endogenous protective factor against iron−induced nephrotoxicity by mitigating oxidative damage and maintaining mitochondrial stability. These findings indicate that ALDH1a3 is a promising potential therapeutic target for the treatment of iron overload−related kidney diseases. Full article

This study investigates a combined advanced oxidation process (AOP) utilizing UVA-LED irradiation (365 nm) for the degradation of sucralose (SUC), a complex artificial sweetener that poses a challenge for wastewater treatment due to its resistance to conventional methods. A sequential treatment strategy was employed. The initial step utilized UVA-activated persulfate (PS) at varying dosages (0.12–0.5 g/L) and UVA fluence rate (ranging from 20 to 100% of nominal output). The influence of natural water components (bicarbonate, chloride, sulfate, and nitrate) on PS activation was systematically analyzed. Notably, the substantial pH decrease during oxidation opened the possibility of replacing an amount of PS with the less expensive and more environmentally friendly hydrogen peroxide (H₂O₂) in the subsequent Fenton reaction. This second step employed a stoichiometric dosage of H₂O₂ (2.12 g/g COD) and varying Fe²⁺ concentrations (0.05–0.2 g/L), achieving a 95% overall mineralization within 60 min. The combined process incurred an approximate cost of 2.5€ per m³. This research contributes to the development of more effective and environmentally friendly wastewater treatment strategies for emerging contaminants. Full article

Manganese dioxide (MnO₂) modified biochar catalysts derived from biomass and waste polymer feedstocks were synthesized and evaluated as heterogeneous Fenton-like catalysts for solar-driven degradation of Rhodamine B (RhB) in aqueous systems. Biochars produced from maple wood and plastic waste (high-density polyethylene) provided porous carbon matrices with oxygen-rich surface functionalities that enabled effective MnO₂ loading and catalytic activity. Photocatalytic experiments conducted under real sunlight using a solar-collector reactor demonstrated faster RhB degradation compared to a conventional ultraviolet (UV) system, confirming the advantage of solar-driven operation. Complete RhB removal was achieved at initial concentrations of 100–300 ppm, whereas higher dye concentrations (500 ppm) exceeded the catalytic capacity within the tested reaction time. Kinetic analysis revealed catalyst-dependent reaction behaviors, indicating that degradation pathways were strongly influenced by the biopolymer-derived carbon structure and MnO₂ dispersion. Degradation efficiency was correlated with solar irradiance and reactor temperature, with higher UV index conditions enhancing catalytic performance. Reusability tests showed that the catalysts remained active over multiple cycles, although gradual decreases in reaction rates and catalyst recovery were observed. These results demonstrate the potential of biopolymer-derived carbon materials as effective solar-driven catalysts for wastewater treatment applications. Full article

Iron-based nanoparticles, particularly iron oxide nanostructures (IONPs), have emerged as versatile and clinically relevant platforms for drug delivery and theranostic applications. Among these, superparamagnetic iron oxide nanoparticles (SPIONs), including magnetite (Fe₃O₄) and maghemite (γ-Fe₂O₃), are the most extensively investigated due to their biocompatibility, magnetic responsiveness, and established safety profiles. Their unique superparamagnetic behavior enables external magnetic-field-guided targeting, magnetic resonance imaging (MRI) contrast enhancement, and magnetically triggered hyperthermia, enabling simultaneous diagnosis and therapy. Surface functionalization with polymers, silica, lipids, peptides, and biomolecules further improves colloidal stability, circulation time, targeting specificity, and controlled drug release. Core–shell architectures and multifunctional hybrid systems have expanded the therapeutic scope of iron nanoparticles, integrating chemotherapy, gene delivery, photothermal therapy, and Fenton reaction–mediated catalytic therapy. Despite promising preclinical outcomes, challenges remain regarding long-term biosafety, oxidative stress induction, biodistribution, large-scale reproducibility, and regulatory translation. This review summarizes the physicochemical properties, synthesis strategies, surface-engineering approaches, drug-loading mechanisms, and biomedical applications of iron-based nanoparticles, highlighting recent advances in multifunctional and peptide-functionalized systems. Critical considerations for clinical translation and future perspectives in precision nanomedicine are also discussed. Full article

Metal ion-based chemo-immunotherapy is often limited by rigid intracellular metal homeostasis, insufficient reactive oxygen species (ROS) accumulation, and an immunosuppressive tumor microenvironment (TME). To overcome these limitations, we engineered an ATP-responsive, core–shell bimetallic nanoreactor (Cu/ZIF@PDA, termed CZP) featuring a precisely controlled ~25 nm biomimetic polydopamine (PDA) coating. Triggered by elevated tumoral ATP levels, CZP undergoes coordination-induced disassembly and promotes oxidative stress amplification. Specifically, the PDA shell acts as a superoxide dismutase (SOD) mimetic to continuously supply H₂O₂, fueling Cu²⁺-mediated Fenton-like reactions to unleash highly toxic hydroxyl radicals (•OH) while aggressively depleting the intracellular glutathione (GSH) pool. This irreversible oxidative damage, coupled with Zn²⁺-induced mitochondrial dysfunction, triggers profound mitochondrial DNA (mtDNA) leakage. Crucially, this cytosolic DNA robustly activates the cGAS-STING signaling axis, driving a massive surge in immunogenic cell death (ICD) and significantly promoting dendritic cell (DC) maturation. Furthermore, CZP markedly inhibited primary tumor growth in vivo and showed protection in a tumor re-challenge model, accompanied by enhanced dendritic cell maturation. These findings support the potential of this ATP-responsive bimetallic nanoplatform to promote antitumor immune activation. Full article

Fungal decay fundamentally alters moisture transport in wood through complex bio-physical coupling mechanisms that remain poorly understood. Brown-rot fungi such as Coniophora puteana (Schumach.: Fr.) P. Karst. degrade wood through chelator-mediated Fenton (CMF) chemistry, producing hydroxyl radicals that depolymerise cellulose and hemicellulose before significant mass loss. This diffusion-dependent process requires elevated moisture content and leads to structural degradation. However, existing models fail to capture the interaction between boundary-driven fungal colonization, decay-induced property changes, and multi-phase multi-Fickian moisture redistribution, particularly the separate evolution of bound- and free-water phases during decay. Here, we present a transport-response bio-hygrothermal finite element model that couples boundary-driven Monod-type fungal colonization kinetics with multi-phase moisture transport (free water, bound water, vapor) in decaying wood. Although fungal biomass evolution is simulated via a reaction–diffusion equation, decay progression is not derived from biomass–substrate interaction but prescribed independently as an experimentally informed input. The model incorporates decay-modified sorption isotherms, permeability evolution, and boundary-driven biomass influx, along with associated moisture transport, into the governing equations. The model is validated against low-field nuclear magnetic resonance (LF-NMR) measurements of C. puteana decay in Scots pine over 35 days. The model successfully reproduces the experimentally observed moisture evolution: a peak free-water content of 50%–70% during weeks 1–2, followed by a progressive decline, while bound water remains remarkably constant despite advancing decay. Monte Carlo uncertainty quantification demonstrates hierarchical parameter control: bound water is governed solely by thermodynamic factors, while free water responds to interacting biological and physical processes. Time-resolved correlation analysis shows a fundamental transition from colonization-dominated (weeks 1–2) to transport-dominated (weeks 3–5) moisture control, quantitatively explaining the experimentally observed shift from accumulation to depletion. This transport-response framework for analyzing moisture behavior under externally defined decay progression establishes quantitative parameter hierarchies that may inform the development of future substrate-coupled bio-hygrothermal models. 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