Fenton-like Reaction Research Articles

Surface Engineering Enhances Vanadium Carbide MXene-Based Nanoplatform Triggered by NIR-II for Cancer Theranostics.

Despite the advantages of high tissue penetration depth, selectivity, and non-invasiveness of photothermal therapy for cancer treatment, developing NIR-II photothermal agents with desirable photothermal performance and advanced theranostics ability remains a key challenge. Herein, a universal surface modification strategy is proposed to effectively improve the photothermal performance of vanadium carbide MXene nanosheets (L-V2C) with the removal of surface impurity ions and generation of mesopores. Subsequently, MnOx coating capable of T1-weighted magnetic resonance imaging can be in situ formed through surface redox reaction on L-V2C, and then, stable nanoplatforms (LVM-PEG) under physiological conditions can be obtained after further PEGylation. In the tumor microenvironment irradiated by NIR-II laser, multivalent Mn ions released from LVM-PEG, as a reversible electronic station, can consume the overexpression of glutathione and catalyze a Fenton-like reaction to produce ·OH, resulting in synchronous cellular oxidative damage. Efficient synergistic therapy promotes immunogenic cell death, improving tumor-related immune microenvironment and immunomodulation, and thus, LVM-PEG can demonstrate high accuracy and excellent anticancer efficiency guided by multimodal imaging. As a result, this study provides a new approach for the customization of 2D surface strategies and the study of synergistic therapy mechanisms, highlighting the application of MXene-based materials in the biomedical field.

An intelligent Cu/ZIF-8-based nanodrug delivery system for tumor-specific and synergistic therapy via tumor microenvironment-responsive cascade reaction.

Anintelligent nanodrug delivery system (Cu/ZIF-8@GOx-DOX@HA, hereafter CZGDH) consisting of Cu-doped zeolite imidazolate framework-8 (Cu/ZIF-8, hereafter CZ), glucose oxidase (GOx), doxorubicin (DOX), and hyaluronic acid (HA) was established for targeted drug delivery and synergistic therapy of tumors. The CZGDH specifically entered tumor cells through the targeting effect of HA and exhibited acidity-triggered biodegradation for subsequent release of GOx, DOX, and Cu2+ in thetumor microenvironment (TME). The GOx oxidized the glucose (Glu) in tumor cells to produce H2O2 and gluconic acid for starvation therapy (ST). The DOX entered the intratumoral cell nucleus for chemotherapy (CT). The released Cu2+ consumed the overexpressed glutathione (GSH) in tumor cells to produce Cu+. The generated Cu+ and H2O2 triggered the Fenton-like reaction to generate toxic hydroxyl radicals (·OH), which disrupted the redox balance of tumor cells and effectively killed tumor cells for chemodynamic therapy (CDT). Therefore, synergistic multimodal tumor treatment via TME-activated cascade reaction was achieved. The nanodrug delivery system has a high drug loading rate (48.3wt%), and the three-mode synergistic therapy has a strong killing effect on tumor cells (67.45%).

Omeprazole-Loaded Copper Nanoparticles for Mitochondrial Damage Mediated Synergistic Anticancer Activity against Melanoma Cells.

Metallic nanoparticles are promising candidates for anticancer therapies. Among the different metallic systems studied, copper is an affordable and biologically available metal with a high redox potential. Copper-based nanoparticles are widely used in anticancer studies owing to their ability to react with intracellular glutathione (GSH) to induce a Fenton-like reaction. However, considering the high metastatic potential and versatility of the tumor microenvironment, modalities with a single therapeutic agent may not be effective. Hence, to enhance the efficiency of chemotherapeutic drugs, repurposing them or conjugating them with other modalities is essential. Omeprazole is an FDA-approved proton pump inhibitor used in clinics for the treatment of ulcers. Omeprazole has also been studied for its ability to sensitize cancer cells to chemotherapy and induce apoptosis. Herein, we report a nanosystem comprising of copper nanoparticles encapsulating omeprazole (CuOzL) against B16 melanoma cells. The developed nanoformulation exerted significant synergistic anticancer activity when compared with either copper nanoparticles or omeprazole alone by inducing cell death through excessive ROS generation and subsequent mitochondrial damage.

Unveiling the Mechanism and Kinetics of Pollutant Attenuation by Free Radicals Triggered from Goethite in Water Distribution Systems.

Investigating the fate of persistent organic pollutants in water distribution systems (WDSs) is of great significance for preventing human health risks. The role of iron corrosion scales in the migration and transformation of organics in such systems remains unclear. Herein, we determined that hydroxyl (•OH), chlorine, and chlorine oxide radicals are generated by Fenton-like reactions due to the coexistence of oxygen vacancy-related Fe(II) on goethite (a major constituent of iron corrosion scales) and hypochlorous acid (HClO, the main reactive chlorine species of residual chlorine at pH ∼ 7.0). •OH contributed mostly to the decomposition of atrazine (ATZ, model compound) more than other radicals, producing a series of relatively low-toxicity small molecular intermediates. A simplified kinetic model consisting of mass transfer of ATZ and HClO, •OH generation, and ATZ oxidation by •OH on the goethite surface was developed to simulate iron corrosion scale-triggered residual chlorine oxidation of organic compounds in a WDS. The model was validated by comparing the fitting results to the experimental data. Moreover, the model was comprehensively applicable to cases in which various inorganic ions (Ca2+, Na+, HCO3-, and SO42-) and natural organic matter were present. With further optimization, the model may be employed to predict the migration and accumulation of persistent organic pollutants under real environmental conditions in the WDSs.

Cu-TNT hollow nanoreactors: Efficient Fenton-like degradation of organic pollutants across a wide pH range

Advanced oxidation processes (AOPs) operating under neutral to alkaline conditions are highly desirable for industrial applications. This study focuses on the use of Cu-doped titanate (Cu-TNT) hollow nanoreactors to effectively degrade organic pollutants in a Fenton-like manner across a broad pH from 3 to 10. The resulting Cu-TNT material possessed a BET surface area of 391.2 m2/g and pores with sizes between 2 and 20 nm. Experimental results from Fenton-like reactions reveal that Cu-TNT exhibited superior catalytic activity and long-term stability in degrading methyl orange compared to Na-titanate, Fe-titanate, copper ions, cuprous chloride, and solid sphere Cu-doped titanate. Notably, Cu-TNT performed optimally at a pH of 9, with singlet oxygen (1O2) and hydroxyl radicals (•OH) being recognized as the main active components. The improved catalytic efficiency was due to the extensive surface area, efficient mass diffusion in limited space, and quick Cu(Ⅰ)/Cu(Ⅱ) transformations. This study provided a feasible pathway to develop Cu-based nanoreactors as heterogeneous catalysts for highly efficient AOPs.

Facile microwave-assisted synthesis of Sb2O3-CuO nanocomposites for catalytic degradation of p-nitrophenol

Recently, bimetallic nanocomposites have been prepared and used in the fields of sensing, catalysis, energy and medicine. However, there are few reports on the preparation and application of new antimony-metal nanocomposites based on two-dimensional antimonene (AM). Herein, Sb2O3-CuO nanocomposites were facilely synthesized by using microwave-assisted heating the mixture solution of AM and Cu2+ ions and utilized for catalytic degradation of p-nitrophenol (PNP). Interestingly, in the mixed solution of AM and various metal ions (Cu2+, Co2+, Mn2+), only the mixture of AM and Cu2+ ions showed efficient fading and absorption reduction effects on PNP after being heated. A series of characterization on morphology and elemental composition confirmed that the nanocomposites obtained after microwave heating was composed of Sb, Cu, O elements (namely Sb2O3-CuO), and was a layered structure loaded with numerous irregular particles. Compared with other catalysts, the nanocomposite has higher catalytic efficiency (the rate constant of 1.07 s−1), and was capable of degrading 96 % of PNP with only 3 s reaction. Electron spin resonance spectroscopy and liquid chromatography-mass spectrometry analysis demonstrated that the copper-mediated Fenton-like reaction in the nanocomposites induced hydroxyl radicals which can efficiently attack and degrade PNP. This study presents a novel approach to the synthesis of antimony-metal nanocomposites and provides a potential solution for the treatment of organic pollutants.

Brain-targeting biomimetic disguised manganese dioxide nanoparticles via hybridization of tumor cell membrane and bacteria vesicles for synergistic chemotherapy/chemodynamic therapy of glioma

Glioma is a prevalent brain malignancy associated with poor prognosis. Although chemotherapy serves as the primary treatment for brain tumors, its effectiveness is hindered by the limited ability of drugs to traverse the blood–brain barrier (BBB) and the development of drug resistance linked to tumor hypoxia. Herein, we report the creation of hybrid camouflaged multifunctional nanovesicles comprising membranes of tumor C6 cells (mT) and bacterial outer membrane vesicles (OMVs) and co-loaded with manganese dioxide nanoparticles (MnO2 NPs) and doxorubicin (DOX) to synergistically enhance the chemotherapy/chemodynamic therapy (CDT) of glioma. Owing to OMV-mediated BBB penetration and mT-inherited tumor-homing properties, MnO2-DOX@mT/OMVs can penetrate the BBB and enhance the tumor cell-specific uptake of DOX via “proton sponge effect”-mediated lysosomal escape. This enhances the apoptotic effect induced by DOX and minimizing DOX-associated cardiotoxicity by facilitating the accumulation of DOX at the tumor site. Furthermore, the MnO2 NPs in MnO2-DOX@mT/OMVs can generate potent CDT by accelerating the Fenton-like reaction with DOX-generated H2O2 and achieving glutathione (GSH)-depletion-induced glutathione peroxidase 4 (GPX4) inactivation. These results showed that MnO2-DOX@mT/OMVs, designed for brain tumor targeting, significantly inhibited tumor growth and exhibited favorable biological safety. This innovative approach offers the augmentation of anticancer treatment efficacy via a potential combination of chemotherapy and CDT.

Electrochemical activation of peroxymonosulfate facilitated by a stainless-steel scrubber cathode: Transition from non-radical to radical pathway mediated by iron leaching

This study investigated the feasibility and underlying mechanisms of peroxymonosulfate (PMS) activation by a stainless-steel scrubber (SSS) cathode. Experimental findings revealed that the system could achieve 100 % degradation of sulfamethoxazole (SMX) in 30 min at initial pH value ranging from 3 to 9. The activation mechanism was observed to occur in two distinct stages. The first stage was characterized by a non-radical 1O2 dominance (0–6 min), where the activation of PMS and O2 was primarily facilitated through direct electron transfer at the cathode surface. Subsequently, the second stage transitioned to a radical dominance (6–18 min), with SO4− playing a pivotal role. This was attributed to the release of Fe2+ ions resulting from cathodic corrosion, which induced both homogeneous and heterogeneous Fenton-like reactions. The PMS/SSS cathode system exhibited anti-interference against most water matrices, except for HCO3−. Notably, the system demonstrated exceptional performance in the degradation of pollutants within phosphate wastewater samples, suggesting its potential for application in such contexts. In addition, the electrical energy was calculated to be 0.025 kWh·m−3 at a current of 0.01 A and a voltage of approximately 2.0 V, providing significant economic benefits.

Overcoming metals redox rate limitations in spinel oxide-driven Fenton-like reactions via synergistic heteroatom doping and carbon anchoring for efficient micropollutant removal

The transition metals redox rate limitations of spinel oxides during Fenton-like reactions hinder its efficient and sustainable treatment of actual wastewater. Herein, we propose to optimize the electronic structure of Co-Mn spinel oxide (CM) via sulfur doping and carbon matrix anchoring synergistically, enhancing the radicals-nonradicals Fenton-like processes for efficient water decontamination. Activating peroxymonosulfate (PMS) with optimised spinel oxide (CMSAC) achieved near-complete removal of ofloxacin (10 mg/L) within 6 min, showing 8.4 times higher efficiency than CM group. Significantly higher yields of SO4·− and high-valent metal species in CMSAC/PMS system provided exceptional resistance to co-existing anions, enabling efficient removal of various emerging contaminants in high salinity leachate. Specifically, sulfur coordination and carbon anchoring-induced oxygen vacancy synergistically improved the electronic structure and electron transfer efficiency of CMSAC, thus forming highly reactive Co sites and significantly reducing the energy barrier for Co(IV)=O generation. The reductive sulfur species facilitated the conversion of Co(III) to Co(II), thereby maintaining the stability of the catalytic activity of CMSAC. This work developed a synergistic optimization strategy to overcome the metals redox rate limitations of spinel oxides in Fenton-like reactions, providing deep mechanistic insights for designing Fenton-like catalysts suitable for practical applications.

A cancer-targeted glutathione-gated probe for self-sufficient ST/CDT combination therapy and FRET-based miRNA imaging.

Acancer-targeted glutathione (GSH)-gated theranostic probe (CGT probe) for intracellular miRNA imaging and combined treatment of self-sufficient starvation therapy (ST) and chemodynamic therapy (CDT) was developed. TheCGT probe is constructed using MnO2 nanosheet (MS) as carrier material to adsorb the elaborately designed functional DNAs. It can be internalized by cancer cells via specific recognition between the AS1411 aptamer and nucleolin.After CGT probe entering the cancer cells, the overexpressed GSH, as gate-control, can degrade MS to Mn2+ which can be used for CDT by Fenton-like reaction. Simultaneously, Mn2+-mediated CDT can further cascade with the enzyme-like activities (catalase-like activity and glucose oxidase-like activity) of CGT probe, achieving self-sufficient ST/CDT synergistic therapy. Meanwhile, the anchored DNAs are released, achieving in situ signal amplification via disubstituted-catalytic hairpin assembly (DCHA) and FRET (fluorescence resonance energy transfer) imaging of miR-21. The in vitro and in vivo experiments demonstrated that accurate and sensitive miRNA detection can be achieved using the CGT probe. Overall, the ingenious CGT probe opens a new avenue for the development of early clinical diagnosis and cancer therapy.

Novel 131-iodine labeled and ultrasound-responsive nitric oxide and reactive oxygen species controlled released nanoplatform for synergistic sonodynamic/nitric oxide/chemodynamic/radionuclide therapy

Nitric oxide (NO) and reactive oxygen species (ROS) embody excellent potential in cancer therapy. However, as a small molecule, their targeted delivery and precise, controllable release are urgently needed to achieve accurate cancer therapy. In this paper, a novel US-responsive bifunctional molecule (SD) and hyaluronic acid-modified MnO2 nanocarrier was developed, and a US-responsive NO and ROS controlled released nanoplatform was constructed. US can trigger SD to release ROS and NO simultaneously at the tumor site. Thus, SD served as acoustic sensitizer for sonodynamic therapy and NO donor for gas therapy. In the tumor microenvironment, the MnO2 nanocarrier can effectively deplete the highly expressed GSH, and the released Mn2+ can make H2O2 to produce .OH by Fenton-like reaction, which exhibited a strong chemodynamic effect. The high concentration of ROS and NO in cancer cell can induce cancer cell apoptosis ultimately. In addition, toxic ONOO–, which was generated by the reaction of NO and ROS, can effectively cause mitochondrial dysfunction, which induced the apoptosis of tumor cells. The 131I was labeled on the nanoplatform, which exhibited internal radiation therapy for tumor therapy. In −vitro and −vivo experiments showed that the nanoplatform has enhanced biocompatibility, and efficient anti-tumor potential, and it achieves synergistic sonodynamic/NO/chemodynamic/radionuclide therapy for cancer.

Biodegradable Cascade-Amplified Nanotheranostics for Photoacoustic-Guided Synergistic PTT/CDT/Starvation Antitumor in the NIR-II Window.

The development of nanoassemblies, activated by the tumor microenvironment, capable of generating photothermal therapy (PTT) and amplifying the "ROS (·OH) storm," is essential for precise and effective synergistic tumor treatment. Herein, an innovative cascade-amplified nanotheranostics based on biodegradable Pd-BSA-GOx nanocomposite for NIR-II photoacoustic imaging (PAI) guides self-enhanced NIR-II PTT/chemodynamic therapy (CDT)/starvation synergistic therapy. The Pd-BSA-GOx demonstrates the ability to selectively convert overexpressed H2O2 into strongly toxic ·OH by a Pd/Pd2+-mediated Fenton-like reaction at a lower pH level. Simultaneously, the GOx generates H2O2 and gluconic acid, effectively disrupting nutrient supply and instigating tumor starvation therapy. More importantly, the heightened levels of H2O2 and increased acidity greatly enhance the Fenton-like reactivity, generating a significant "·OH storm," thereby achieving Pd2+-mediated cascade-amplifying CDT. The specific PTT facilitated by undegraded Pd accelerates the Fenton-like reaction, establishing a positive feedback process for self-enhancing synergetic PTT/CDT/starvation therapy via the NIR-II guided-PAI. Therefore, the multifunctional nanotheranostics presents a simple and versatile strategy for the precision diagnosis and treatment of tumors.

Oxalic Acid-Assisted Photo-Fenton Catalysis Using Magnetic Fe3O4 Nanoparticles for Complete Removal of Textile Dye

Textile industry effluents contain several hazardous substances, such as dye-containing effluents, which pose environmental and aesthetic challenges. Presently, the microbial-based remediation process is in use. This study investigated the application of ferrous–ferric oxide (Fe3O4) nanoparticles, a readily formulated nanoadsorbent, to remove scattered dye molecules from industrial effluents. The ferrous–ferric oxide nanoparticles were prepared using a chemical co-precipitation method. The nanoparticles had 26.93 emu g−1 magnetization, with sizes smaller than 20 nm, and possessed a highly purified cubic spinel crystallite structure. The catalytic activity of the iron oxide depended on the dose, photocatalytic enhancer, i.e., H2O2 level, pH of the reaction medium, and dye concentration. We optimized the Fenton-like reaction to work best using 1.0 g/L of ferrous–ferric oxide nanoparticles, 60 mM oxalic acid at pH 7.0, and 60 ppm of dye. Iron oxides act as photocatalysts, and oxalic acid generates electron–hole pairs. Consequently, higher amounts of super-radicals cause the rapid degradation of dye and pseudo-first-order reactions. Liquid chromatography–mass spectrometry (LC-MS) analysis revealed the ferrous–ferric oxide nanoparticles decolorized and destroyed Disperse Red 277 in 180 min under visible light. Hence, complete demineralization is observed using a photo-Fenton-like reaction within 3 h under visible light. These high-capacity, easy-to-separate next-generation adsorption systems are suggested to be suitable for industrial-scale use. Ferrous–ferric oxide nanoparticles with increased adsorption and magnetic properties could be utilized to clean environmental pollution.

Enhancing catalyst stability: Immobilization of Cu–Fe catalyst in sodium alginate matrix for methyl orange removal via Fenton-like reaction

This study aims to enhance the stability and effectiveness of heterogeneous catalysts in Fenton-like reactions, explicitly addressing the acidity limitations inherent in traditional Fenton processes. Copper-iron was synthesized through co-precipitation, and a catalyst bead was produced from hydrogel formation. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) confirm phases in the bimetallic Copper-iron, aligning with the intended composition. Modification with alginate led to reduced metal leaching compared to the bare bimetallic counterpart, as confirmed by atomic absorption spectroscopy (AAS). Additionally, Fourier-transform infrared spectroscopy (FTIR) revealed the deactivation of alginate through the disappearance of carboxyl groups, indicating the depolymerization of the catalyst bead. Under the suggested conditions (Methyl Orange concentration of 25 mg/L, initial solution pH of 7, 2 g/L catalyst loading, concentration of hydrogen peroxide 100 mM in a 120-min reaction time), the catalyst demonstrated remarkable decolorization efficiency of Methyl Orange, achieving 97.67 %. Further highlighting its practicality, the catalyst exhibited outstanding reusability over four cycles under identical conditions, showcasing robust immobilization capabilities and sustained performance. Notably, the catalyst's magnetic properties facilitated easy separation using an external magnet. In conclusion, the developed catalyst beads offer a solution with high reusability, magnetic separability, and reduced iron leaching. The advantageous characteristics underscore its potential as a heterogeneous catalyst for wastewater treatment applications, warranting further exploration under practical conditions.

Boosted adsorption and oxidation performances in peroxymonosulfate (PMS)-based heterogeneous fenton-like reactions via P, N co-doping strategy

The heterogeneous Fenton-like reactions (HTFR) have attracted considerable interest for their efficacy in degrading pollutants. However, the development of effective strategies for enhancing performance in HTFR remains a subject of ongoing research. Herein, a synergistic adsorption and oxidation-dominated process was developed to overcome the bottlenecks of peroxymonosulfate (PMS)-based HTFR in terms of mass transfer and catalyst reactivity. Heteroatom (P, N) co-doping for manganese (Mn) was employed to fabricate an efficient catalyst, Mn@5-NPC-800, which exhibited exceptional abilities of adsorption and PMS activation. The enhanced performance of HTFR was attributed to the increased specific surface area (SSA) and enhanced yields of graphitic-N/MnIII of the catalyst, which facilitated reactant enrichment and electron transfer in the delocalized conjugated area, respectively. The PMS-based HTFR induced by Mn@5-NPC-800 for pollutant removal was characterized by a synergistic adsorption and reactive oxygen species (ROS)-dominated oxidation process. DFT calculations revealed that the N, P co-doped carbon matrix (NPC) acted as a conductive bridge, significantly improving electron transfer between MnP and PMS molecule, which was identified as a key factor in governing the catalytic performance. The investigation presents a suggestive example of employing a doping strategy to create a synergistic effect of adsorption and oxidation, thereby strengthening the performance of Fenton-like reactions.

PH-dependent mechanisms of sulfadiazine degradation by natural pyrite-driven heterogeneous Fenton-like reactions

The development of a natural pyrite/peroxymonosulfate (PMS) system for the removal of antibiotic contamination from water represented an economic and green sustainable strategy. Yet, a noteworthy knowledge gap remained considering the underlying reaction mechanism of the system, particularly in relation to its pH sensitivity. Herein, this paper investigated the impacts of critical reaction parameters and initial pH levels on the degradation of sulfadiazine (SDZ, 3 mg/L) in the pyrite/PMS system, and elucidated the pH dependence of the reaction mechanism. Results showed that under optimal conditions, SDZ could be completely degraded within 5 min at a broad pH range of 3.0–9.0, with a pseudo-first-order reaction rate of >1.0 min−1. The low or high PMS doses could lower degradation rates of SDZ through the decreased levels of active species, while the amount of pyrite was positively correlated with the removal rate of SDZ. The diminutive concentrations of anions exerted minor impacts on the decomposition of SDZ within the pyrite PMS system. Mechanistic results demonstrated that the augmentation of pH levels facilitated the transition from the non-radical to the radical pathway within the natural pyrite/PMS system, while concurrently amplifying the role of •OH in the degradation process of SDZ. This could be attributed to the change in interface electrostatic repulsion induced by pH fluctuations, as well as the mutual transformation between active species. The stable presence of the relative content of Fe(II) in the used pyrite was ensured owing to the reduced sulfur species acting as electron donors, providing the pyrite/PMS system excellent reusability. This paper sheds light on the mechanism regulation of efficient removal of organic pollutants through pyrite PMS systems, contributing to practical application.

Enhanced mineralization of bisphenol A by electric arc furnace slag: Fenton-like oxidation

Bisphenol A (BPA) aqueous solution was treated through a heterogeneous Fenton-like oxidation process with electric arc furnace slag (EAFS), a waste product from an Argentinian steel processing plant, as the catalyst. SEM/EDS, XRD, and Mössbauer spectroscopy characterization revealed a significant presence of Fe and minor amounts of Cu and Mn in EAFS, known to play active roles in the Fenton-like reactions. The predominant crystalline form of iron in EAFS was magnesiowüstite, accompanied by minor amounts of hematite, magnetite, maghemite, and metallic iron. Batch Fenton-like oxidation experiments were conducted under acidic conditions (pH 2.8–3), examining the effect of temperature (25, 50, and 70 °C) and catalyst load (0.1, 0.5, and 1 g/L) on BPA degradation and mineralization over 180 min. BPA was completely degraded within the first minutes, while mineralization levels improved from 40% to an outstanding 70% as the temperature increased from 25 to 70 °C. The catalyst gradually lost its activity after five cycles at 25 °C, but raising the temperature up to 70 °C allowed maintaining mineralization levels between 70 and 50% over ten cycles. The oxidation process involved a combined Fenton-like homogeneous/heterogeneous mechanism, and deactivation was linked to a lower leaching of active cations over the cycles, reduction of the Fe(II)/Fe(III) ratio in the iron phases, and blocking of active sites by adsorption of reaction intermediates. EAFS demonstrated an exceptional performance in the Fenton-like oxidation of BPA. The utilization of this type of industrial waste materials represents a promising technological alternative that could benefit both steel processing and water treatment plants.

Nitro-functionalization on MIL-53(Fe) for PCMX degradation: Elevating Fenton-like catalytic propelled by abundant reaction sites and iron cycle

To address the issue of excessive residues of 4-chloro-3,5-dimethylphenol (PCMX) in the water environment. In a one-step solvothermal process, iron-based metal-organic frameworks (Fe-MOFs) material MIL-53(Fe) undergoes a synthetic modification strategy. 2-Nitroterephthalic acid as an organic ligand reacted with Fe3+ in a solvothermal process lasting 18 h to yield the nitro-functionalized MIL-53(Fe)–NO2(18h). The objective was to augment the abundance of Fe central unsaturated coordination sites (Fe CUCs) and expedite the Fe(III)/Fe(II) redox cycle, thereby enhancing the heterogeneous Fenton-like treatment capability of pollutants. MIL-53(Fe)–NO2(18h) has excellent hydrogen peroxide (H2O2) catalytic activity and PCMX degradation across a broad pH spectrum (4.0∼8.0). Almost complete removal of PCMX was achieved within 30 min, while pseudo-first-order kinetic rate constants (kobs) increased 4.37 times over MIL-53(Fe). The confirmation of increased Fe CUCs abundance in MIL-53(Fe)–NO2(18h) was achieved through Lewis acidity, oxygen vacancies (OVs) signals, and Fe–O coordination characterization results. Density functional theory (DFT) calculations revealed that Fe CUCs in MIL-53(Fe)–NO2(18h) exhibits heightened affinity for H2O2 adsorption, showcasing stronger charge transfer and enhanced H2O2 dissociation ability. The Fe(III)/Fe(II) redox cycle, a driving force of Fenton-like reactions, was notably improved in the nitro-modified materials. These enhancements significantly expedited the Fenton-like process, resulting in the generation of increased amounts of reactive oxygen species (ROSs), with hydroxyl radicals (OH·) being pivotal components in degradation. The MIL-53(Fe)–NO2(18h)/H2O2 system has demonstrated versatility in treating a variety of emerging contaminants, achieving removal efficiencies exceeding 99.7% for other antibiotics and endocrine disruptors within 60 min. Furthermore, MIL-53(Fe)–NO2(18h) demonstrated outstanding reusability and adaptability in actual water environments. This study introduces a straightforward and environmentally friendly strategy for remediating environmental pollution using Fe-MOF-catalysed heterogeneous Fenton-like technology.

In Situ Synthesis of Cu2O Nanoparticles Using Eucalyptus globulus Extract to Remove a Dye via Advanced Oxidation.

Water pollution, particularly from organic contaminants like dyes, is a pressing issue, prompting exploration into advanced oxidation processes (AOPs) as potential solutions. This study focuses on synthesizing Cu2O on cellulose-based fabric using Eucalyptus globulus leaf extracts. The resulting catalysts effectively degraded methylene blue through photocatalysis under LED visible light and heterogeneous Fenton-like reactions with H2O2, demonstrating reusability. Mechanistic insights were gained through analyses of the extracts before and after Cu2O synthesis, revealing the role of phenolic compounds and reducing sugars in nanoparticle formation. Cu2O nanoparticles on cellulose-based fabric were characterized in terms of their morphology, structure, and bandgap via SEM-EDS, XRD, Raman, FTIR, UV-Vis DRS, and TGA. The degradation of methylene blue was pH-dependent; photocatalysis was more efficient at neutral pH due to hydroxyl and superoxide radical production, while Fenton-like reactions showed greater efficiency at acidic pH, primarily generating hydroxyl radicals. Cu2O used in Fenton-like reactions exhibited lower reusability compared to photocatalysis, suggesting deterioration. This research not only advances understanding of catalytic processes but also holds promise for sustainable water treatment solutions, contributing to environmental protection and resource conservation.

Mn(II)-Aloe-Emodin Nanoscale Coordination Polymer Enhances Ferroptosis by Synergistically Enhancing Reactive Oxygen Species Generation via the Nrf2-GPX4 Axis.

Ferroptosis induction is particularly promising for cancer therapy when the apoptosis pathway is compromised. Current strategies in nanomedicine for inducing ferroptosis primarily focus on promoting the accumulation of reactive oxygen species (ROS). However, the presence of intracellular antioxidants, such as nuclear factor erythroid 2-related factor 2 (Nrf2), can limit the effectiveness of such therapy by activating detoxification systems and eliminating ROS. To overcome this challenge, we developed a synergistic ferroptosis-inducing agentby modifying manganese (Mn2+)-1,8-dihydroxy-3-hydroxymethyl-anthraquinone (aloe-emodin, AE) with polyvinyl pyrrolidone (PVP) to create nanoparticles (MAP NPs). In the tumor microenvironment, these NPs degraded and released AE and Mn(II), facilitating the generation of ROS and Mn(IV) through a Fenton-like reaction between hydrogen peroxide (H2O2) and Mn(II). Mn(IV) subsequently interacts with glutathione (GSH) to induce a cyclic catalytic effect, and the depletion of GSH diminished the activation of glutathione-dependent peroxidase 4 (GPX4). Furthermore, AE inhibits the activity of Nrf2 and depleted GSH, thereby synergistically enhancing antitumor efficacy. Here it is demonstrated that MAP NPs effectively generate a robust ROS storm within tumor cells, suggesting that high-performance ferroptosis therapy is effective. Additionally, the inclusion of Mn(II) in the MAP NPs enables real-time monitoring of therapeutic efficacy via magnetic resonance T1-weighted contrast imaging.