Search Results (647)

The precise synthesis of non-precious metal single-atom electrocatalysts is crucial for enhancing the yield of highly active reactive oxygen species (ROSs). Conventional oxidation methods, such as Fenton or NaClO processes, suffer from poor efficiency, high energy demand, and secondary pollution. In contrast, heterogeneous electro-Fenton systems based on cascade oxygen reduction reactions (ORRs), which require low operational voltage and cause pollutant degradation through both direct electron transfer and ROS generation, have emerged as a promising alternative. Recent studies showed that carbon cathodes decorated with atomically dispersed transition metals can effectively integrate the excellent conductivity of carbon supports with the tunable surface chemistry of metal centers. However, the electronic structure of active sites intrinsically hinders the simultaneous achievement of high activity and selectivity in cascade ORRs. This review summarizes the advances, specifically from 2020 to 2025, in understanding the mechanism of cascade ORRs and the synthesis of transition metal-based single-atom catalysts in cathode electrocatalysis for efficient wastewater treatment, and discusses the key factors affecting treatment performance. While employing atomically engineered cathodes is a promising approach for energy-efficient wastewater treatment, future efforts should overcome the barriers in active site control and long-term stability of the catalysts to fully exploit their potential in addressing water pollution challenges. Full article

Antioxidative neuroprotection is effective at preventing ischemic stroke (IS). Ferulic acid (FA) offers benefits in the treatment of many diseases, mostly due to its antioxidant activities. In this study, a glycosylated ferulic acid conjugate (FA-Glu), with 1,2,3-triazole as a linker and bioisostere between glucose at the C6 position and FA at the C4 position, was designed and synthesized. The hydrophilicity and chemical stability of FA-Glu were tested. FA-Glu’s protection against DNA oxidative cleavage was tested using pBR322 plasmid DNA under the Fenton reaction. The cytotoxicity of FA-Glu was examined via the PC12 cell and bEnd.3 cell tests. Antioxidative neuroprotection was evaluated, in vitro, via a H₂O₂-induced PC12 cell test, measuring cell viability and ROS levels. Antioxidative alleviation of cerebral ischemia–reperfusion injury (CIRI), in vivo, was evaluated using a rat middle cerebral artery occlusion (MCAO) model. The results indicated that FA-Glu was water-soluble (LogP −1.16 ± 0.01) and chemically stable. FA-Glu prevented pBR322 plasmid DNA cleavage induced via •OH radicals (SC% 88.00%). It was a non-toxic agent based on PC12 cell and bEnd.3 cell tests results. FA-Glu significantly protected against H₂O₂-induced oxidative damage in the PC12 cell (cell viability 88.12%, 100 μM) and inhibited excessive cell ROS generation (45.67% at 100 μM). FA-Glu significantly reduced the infarcted brain areas measured using TTC stain observation, quantification (FA-Glu 21.79%, FA 28.49%, I/R model 43.42%), and H&E stain histological observation. It sharply reduced the MDA level (3.26 nmol/mg protein) and significantly increased the GSH level (139.6 nmol/mg protein) and SOD level (265.19 U/mg protein). With superior performance to FA, FA-Glu is a safe agent with effective antioxidative DNA and neuronal protective actions and an ability to alleviate CIRI, which should help in the prevention of IS. Full article

The current work is established with the object of modifying the source of Fenton system and substituting iron source as a catalyst with magnetite/potato peels composite material (POT400-M) to be an innovative solar photocatalyst. The structural and morphological characteristics of the material are assessed through X-ray diffraction (XRD) and scanning electron microscopy (SEM). The technique is applied to treat oil spills that pollute seawater. The effectiveness of the operating parameters is studied, and numerical optimization is applied to optimize the most influential parameters on the system, including POT400-M catalyst (47 mg/L) and hydrogen peroxide reagent (372 mg/L) at pH 5.0, to maximize oil removal, reaching 93%. Also, the aqueous solution and wastewater temperature on the oxidation reaction is evaluated and the reaction exhibited an exothermic nature. Kinetic modeling is evaluated, and the reaction is found to follow the second-order kinetic model. Thermodynamic examination of the data exhibits negative enthalpy (ΔH′) values, confirming that the reaction is exothermic, and the system is verified to be able to perform at the minimal activation energy barrier (−51.34 kJ/mol). Full article

The increasing threat of antimicrobial resistance (AMR), along with the limited availability of new lead compounds in the drug development pipeline, highlights the urgent need to discover antimicrobial agents with innovative mechanisms of action. In this regard, metal complexes offer a unique opportunity to access mechanisms distinct from those of conventional antibiotics. Although iron (Fe) is an essential element for all forms of life, including pathogenic bacteria, it also poses a serious risk of cytotoxicity due to its redox activity, which can trigger the production of reactive oxygen species (ROS) via the Fenton reaction. This review highlights recent advances in the development of iron-based antimicrobial agents that harness the toxicity resulting from dysregulated iron uptake, thereby inducing bacterial cell death through oxidative stress. These findings may guide the development of effective treatments for pathogenic infections and offer new perspectives on leveraging redox chemistry of iron to combat the growing threat of global bacterial resistance. Full article

The olive oil-production sector engages with the environment on multiple levels, and the valorization of olive pomace (OP) has emerged as a key strategy to improve the entire system’s sustainability. Numerous studies have investigated the biological effects of OP phenolic fraction for nutraceutical applications, highlighting its antioxidant properties. This study aimed to assess the effect of an OP extract (OPE) and its phenolic content on ferroptosis induced by RAS-selective lethal 3 (RSL3), an inhibitor of glutathione peroxidase 4. After characterization of OPE phenolic composition, its antioxidant properties were confirmed through the Fenton reaction assay. Subsequently, we examined the effect of OPE on ter-butyl hydroperoxide-induced ROS generation and lipid peroxidation in TPH-1 and HIECs cells and found that OPE reduced ROS and lipid peroxidation. RSL3 decreased the number of vital cells, which was associated with an elevation in ROS and lipid peroxidation, and a reduction in GSH. Interestingly, all these detrimental effects were reversed by OPE. Furthermore, OPE was also found to significantly increase GSH and the GSH/GSSG ratio per se. In conclusion, the fact that OPE decreases ROS and lipid peroxidation induced by RSL3 and augments GSH and cell viability suggests that OPE has potential as a ferroptosis inhibitor. Full article

This study investigates the influence of divalent metals—(Mg(II), Co(II), and Ni(II)) in layered double hydroxides (LDHs), with a constant trivalent Fe(III) component—on the decoloration of crystal violet and methyl blue dyes via a Fenton-type oxidation reaction. The catalysts, synthesized by co-precipitation and hydrothermal treatment, were tested in both hydroxide and oxide forms under varying agitation conditions (0 and 280 rpm). A 2² × 3 factorial design was used to analyze the effect of the divalent metal type, catalyst phase, and stirring. The Mg/Fe oxide, with the highest BET surface area (144 m²/g) and crystallite size (59.7 nm), showed superior performance—achieving up to 98% decoloration of crystal violet and 97% of methyl blue within 1 h. The kinetic analysis revealed pseudo-second-order and pseudo-first-order fits for crystal violet and methyl blue, respectively. These findings suggest that LDH-based catalysts provide a fast, low-cost, and effective option for dye removal in aqueous systems. Full article

In this study, the degradation of Nile Blue dye was investigated using homogeneous and heterogeneous photocatalytic methods based on the photo-Fenton reaction. More specifically, for homogeneous photocatalysis, the classical photo-Fenton (UV/Fe²⁺/H₂O₂) and modified photo-Fenton-like (UV/Fe²⁺/S₂O₈²⁻) systems were studied, while for heterogeneous photocatalysis, a commercial MOF catalyst, Basolite F300, and a natural ferrous mineral, geothite, were employed. Various parameters—including the concentrations of the oxidant and catalyst, UV radiation, and pH—were investigated to determine their influence on the reaction rate. In homogeneous systems, an increase in iron concentration led to an enhanced degradation rate of the target compound. Similarly, increasing the oxidant concentration accelerated the reaction rate up to an optimal level, beyond which radical scavenging effects were observed, reducing the overall efficiency. In contrast, heterogeneous systems exhibited negligible degradation in the absence of an oxidant; however, the addition of oxidants significantly improved the process efficiency. Among the tested processes, homogeneous techniques demonstrated a superior efficiency, with the conventional photo-Fenton process achieving complete mineralization within three hours. Kinetic analysis revealed pseudo-first-order behavior, with rate constants ranging from 0.012 to 0.688 min⁻¹ and correlation coefficients (R²) consistently above 0.90, confirming the reliability of the applied model under various experimental conditions. Nevertheless, heterogeneous techniques, despite their lower degradation rates, also achieved high removal efficiencies while offering the advantage of operating at a neutral pH without the need for acidification. Full article

In this investigation, a hierarchical FeCo-layered double hydroxide (FeCo-LDH) electrochemical membrane material was prepared by a simple in situ hydrothermal method. The prepared material formed a 3D honeycomb-structured FeCo-LDH-modified carbon felt (FeCo-LDH/CF) catalytic layer with uniform open pores on a CF substrate with excellent catalytic activity and was served as the cathode in a flow-through electro-Fenton (FTEF) reactor. The electrocatalyst demonstrated excellent treatment performance (99%) in phenol simulated wastewater (30 mg L⁻¹) under the optimized operating conditions (applied voltage = 3.5 V, pH = 6, influent flow rate = 15 mL min⁻¹) of the FTEF system. The high removal rate could be attributed to (i) the excellent electrocatalytic oxidation performance and low interfacial charge transfer resistance of the FeCo-LDH/CF electrode as the cathode, (ii) the ability of the synthesized FeCo-LDH to effectively promote the conversion of H₂O₂ to •OH under certain conditions, and (iii) the flow-through system improving the mass transfer efficiency. In addition, the degradation process of pollutants within the FTEF system was additionally illustrated by the •OH dominant ROS pathway based on free radical burst experiments and electron paramagnetic resonance tests. This study may provide new insights to explore reaction mechanisms in FTEF systems. Full article

The extensive use of herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA), coupled with its limited biodegradability, has led to its ubiquitous presence in aquatic environments. This work investigates the removal of MCPA (100 mg/L) in the aqueous phase via solar photo-Fenton. The process was carried out in a 700 mL reactor using a Xe lamp that simulates solar radiation (λ: 250–700 nm). A parametric study was conducted to assess the influence of dissolved O₂ on the reaction medium, Fe²⁺ dosage, H₂O₂ concentration and pH₀. The results indicate that dissolved O₂ boosts pollutant mineralization, even working at sub-stoichiometric H₂O₂ concentrations. Under optimal reaction conditions ([Fe²⁺]: 7.5 mg/L, [H₂O₂]₀: 322 mg/L (stoichiometric dose), pH₀: 3.5), the MCPA reached almost complete mineralization (X_TOC: 98.40%) in 180 min. Phytotoxicity and ecotoxicity assessments of treated effluents revealed that even working at sub-stoichiometric H₂O₂ dosages, toxicity decreases with the solar photo-Fenton treatment. Finally, the solar photo-Fenton process was evaluated in relevant matrices (river water and WWTP secondary effluent) and a realistic pollutant concentration (100 µg/L). In all cases, the pollutant degradation was ≥70% in 60 min, demonstrating the potential of this technology as a tertiary treatment. Full article

Sulfamethazine (SMT) is an antibiotic with good antimicrobial effect and is widely used to treat human and livestock diseases. Though the degradation of SMT by the conventional Fenton and electro-Fenton (EF) processes is efficient, it is limited by a narrow pH and iron sludge generation. Herein, we constructed a cost-effective EF system with the synergistic effect of zero-valent iron (Fe⁰) and sulfite (Fe⁰-EF/Sulfite), and key parameters such as applied current, catalyst dosing, sulfite dosage, and initial pH were optimized. Under the optimal conditions (Fe⁰ dosing of 50 mg/L, sulfite dosage of 1.5 mM, current of 40 mA, and pH of 3), the removal efficiency of 10 mg/L SMT reached 100% within 30 min, and the degradation rate constant reached 0.194 min⁻¹. Electron paramagnetic resonance (EPR) analysis and quenching experiments confirmed the generation of various reactive oxygen species (ROS), such as ^•OH, SO₄⁻, O₂⁻, and ¹O₂, which significantly improved the pollutant removal efficiency. Sulfite accelerated iron cycling and inhibited the formation of iron sludge, thus broadening the pH range of the reaction from three to eight and overcoming the limitations of the conventional EF process. The Fe⁰-EF/Sulfite system performs cost-effectively at a wide pH range, providing an efficient and low-carbon solution for environmental pollution remediation with broad application prospects. Full article

Chronic inflammation plays a pivotal role in human health, with certain inflammatory conditions significantly increasing the risk of cancer, while others do not. However, the molecular mechanisms underlying this divergent risk remain poorly understood. In this study, we propose FR-BINN, a biologically informed neural network framework for disease prediction and interpretability. Incorporating Fenton reaction (FR)-related biological priors and leveraging multiple interpretability methods, FR-BINN identifies key genes driving cancer-prone and non-cancer-prone chronic inflammatory diseases. The experimental results demonstrate that FR-BINN achieves superior classification performance while offering biologically interpretable insights. Moreover, attribution results derived from different explainable techniques show high consistency, and intra-method results exhibit distinct patterns across disease categories. We further combine large language models with feature attributions to identify candidate biomarkers, and independent datasets confirm the robustness of these findings. Notably, genes such as NCOA1 and SDHB are identified as being associated with cancer susceptibility. The framework further reveals distinct patterns in energy metabolism, oxidative stress, and pH regulation between cancer-prone and non-cancer-prone inflammatory diseases. These insights enhance our understanding of inflammation-associated tumorigenesis and contribute to the identification of potential biomarkers and therapeutic targets. Full article

In this study, a pH-responsive nanophotosensitizer (MT@Ce6) was rationally developed by strategic integration of MIL-101 (Fe)-NH₂ metal–organic framework with tannic acid (TA) and chlorin e6. This nanocomposite exhibits pH-responsive degradation in acidic microenvironments, facilitating Fe³⁺ release and subsequent reduction to Fe²⁺ that catalyzes Fenton reaction-mediated hydroxyl radical (•OH) generation. This cascade reaction shifts reactive oxygen species (ROS) predominance from transient singlet oxygen (¹O₂) to the long-range penetrative •OH, achieving robust biofilm disruption and over 90% eradication of methicillin-resistant Staphylococcus aureus (MRSA) under 660 nm irradiation. In vivo evaluations revealed accelerated wound healing with 95% wound closure within 7 days, while species-selective antibacterial studies demonstrated a 2.3-fold enhanced potency against Gram-positive bacteria due to their unique peptidoglycan-rich cell wall architecture. These findings collectively establish a microenvironment-adaptive nanoplatform for precision antimicrobial interventions, providing a translational strategy to address drug-resistant infections. Full article

Controlled iron extraction from iron-based sludge (Fe-Sludge) drainage and its use as a Fenton’s reagent is investigated in the current study for eliminating organics from launderette discharge stream. The influences of the iron dosage, hydrogen peroxide concentration, and pH are assessed as treatment factors for their direct impact on the oxidation of organic compounds. Additionally, optimal oxidation conditions are determined using the response surface methodology (RSM) technique, and the ranges of treatment variables are analyzed. The optimum values of a pH of 2.0, Fe sludge concentration of 99 mg/L, and H₂O₂ content of 402 mg/L resulted in optimal organics removal of up to 98%, expressed as Chemical Oxygen Demand (COD) removal. The oxidation efficacy attained from the design is confirmed and the model validation is assessed, and the suggestive model is accepted since it possesses a correlation coefficient of 97.7%. The thermodynamic and kinetic models are also investigated, and the reaction showed that the temperature increases resulted in the oxidation efficiency being reduced. The oxidation efficiency expressed as COD reduction is clearly characterized by first-order reaction kinetics. The thermodynamic characteristics indicated that the oxidation reaction was exothermic and not spontaneous. Full article

Iron–carbon micro-electrolysis and combined processes were used to treat simulated dyeing wastewater containing direct Big Red 4BE dye (concentration of 1500 mg/L, chromaticity of 80,000 times, and salt content of 20 g/L). Through single-factor experiments, the optimal reaction conditions were determined as follows: reaction time of 110 min, initial pH of 5, and iron and carbon mass ratio of 1:2. Under the optimal conditions, the concentration was reduced to 14.51 mg/L, the chromaticity was reduced to 3000 times, and the decolorization rate reached 99.03%. In order to further decrease the wastewater chromaticity, coagulation and Fenton oxidation were respectively employed for in-depth treatment after iron–carbon micro-electrolysis. The total decolorization rate of the dye wastewater exceeded 99.7%, with the treated effluent meeting the specified chromaticity discharge standard (80-fold). The integrated processes of iron–carbon micro-electrolysis combined with either coagulation sedimentation or Fenton oxidation demonstrated superior performance in treating direct Big Red 4BE dye wastewater. Full article

The kinetics of the depolymerization of natural rubber (NR) to hydroxyl-terminated natural rubber (HTNR) by hydrogen peroxide (H₂O₂) in the presence of a Fenton catalyst within an acidic milieu and under ultraviolet radiation has been rigorously examined utilizing infrared spectroscopy to determine the alterations in molar mass and the functional characteristics. The kinetic model was analyzed in accordance with the elementary reaction, encompassing the following mechanisms: the interaction between hydroxyl radicals and NR, producing radical NR and hydroxylated NR; the reaction wherein radical NR and hydroxyl radicals yield hydroxylated NR; and the subsequent reaction of hydroxylated NR with hydroxyl radicals producing lower radical NR, hydroxylated terminated NR, radical NR, and hydroxylated NR. The conversion of the NR polymer and the total hydroxyl content were discerned at the absorption bands of the CH₂-CH₂ and OH groups located at 850 cm⁻¹ and 3400 cm⁻¹, respectively. The absorption peak at 1850 cm⁻¹ attributed to CH₃ was employed as the reference group for calibration. The influence of the temperature on the depolymerization process conformed to the Arrhenius equation, characterized by activation energies of 750 K and 1200 K. The impact of the H₂O₂/Fenton ratio on the depolymerization process follows a power law with power coefficients of 1.97 and 1.82. Full article