Superoxide Research Articles

Developing highly efficient photocatalysts for purifying polluted water and degrading organic contaminants has attracted increasing attention. The generation of singlet oxygen (1O2) and superoxide radicals (O2•-) remains a key challenge for achieving high catalytic performance. Herein, a range of metal-organic frameworks (MOFs), denoted as {[MBPDC)]·H2O}n (M = Fe2+ (MOF 1), Co2+ (MOF 2), and Ni2+ (MOF 3); H2BPDC = 2,2'-bipyridine-5,5'-dicarboxylic acid), served as an efficient peroxymonosulfate (PMS) activator for the regioselective oxidation of organic pollutants. Photocatalytic experiments revealed that MOF 2 exhibited superior degradation efficiency toward Rhodamine B (RhB), achieving 99.4% removal within 12 min, significantly faster than MOF 1 (4.5%) and MOF 3 (10.0%). Notably, MOF 2 demonstrated excellent reusability and structural robustness over five consecutive cycles. Through integrated radical scavenging tests and electron paramagnetic resonance (EPR) spectroscopy, 1O2 and O2•- were determined to be the key reactive oxygen species driving the degradation process. The outstanding durability and anti-interference capacity of MOF 2 underscore its practical potential for cost-effective and robust environmental remediation applications.

This study transformed discarded courgette biomass into biochar (BC) via pyrolysis at 500 °C and employed it as an activator of potassium periodate (PI) for atrazine (ATZ) degradation. Characterization analyses confirmed that the synthesized BC possessed a porous structure, a high carbon content (76.13%), crystalline SiO2, KCl, and CaCO3 phases, as well as abundant oxygen-containing functional groups (–OH, C=O, C=C, –COOH), which are favorable for catalytic activation. The point of zero charge of 4.25 indicates that the BC surface carries a suitable charge distribution, promoting effective electrostatic interactions under near-neutral pH conditions. Under optimal operating conditions (neutral pH, [ATZ]o = 7.3 mg/L, [PI]o = 2.7 mM, [BC]o = 0.55 g/L, and 25 ± 0.5 °C), the system achieved 99.35% ATZ removal (first-order kinetic rate constant = 0.0601 min−1) and 64.23% TOC mineralization within 60 min. Quenching tests confirmed iodate radicals and singlet oxygen as the primary species, with hydroxyl and superoxide radicals playing secondary roles. The proposed mechanism suggests that electron transfer from oxygen-containing groups on the BC surface activates PI, leading to the generation of reactive oxygen species that facilitate ATZ degradation via synergistic radical and non-radical pathways. The BC catalyst exhibited strong recyclability, with only ~9% efficiency loss after five cycles. The BC/PI system also demonstrated high removal of tetracycline (79.54%) and bisphenol A (85.6%) within 60 min and complete Congo red dye degradation in just 30 min. Application to real industrial wastewater achieved 72.77% ATZ removal, 53.02% mineralization, and a treatment cost of 1.2173 $/m3, demonstrating the practicality and scalability of the BC/PI system for sustainable advanced wastewater treatment.

Electrical treeing, manifesting as Lichtenberg figures (LFs) is a major cause of dielectric failure in power, communication, and aerospace systems. Visualization of LF evolution has been hindered by passive imaging limits. Here, we introduce phosphorescence imaging of Lichtenberg figures (PI-LF), which maps both structural damage and localized oxygen depletion via high-contrast luminescent signals. Guided by a mechanistic understanding of oxygen metabolism in photoactivated phosphorescent systems, indole-core dopants with tunable chromaticity reveal dual oxygen pathways: energy transfer to singlet oxygen and electron transfer to superoxide radicals. Polymer systems doped with these luminophores resolve fine structural progression of electrical trees, enabling bioimaging-style analysis that uncovers a previously hidden spherical-layered growth mode. PI-LF bridges molecular photophysics and high-voltage engineering, establishing a paradigm for luminescence-based visualization of dielectric breakdown.

Although fast-paced ongoing industrial growth, on the one hand, enhances the lifestyle of the population, on the other hand, it affects human health and the environment as a result of the discharge of pollutants. To address this, designing a novel and effective photocatalyst is necessary to mitigate increasing environmental pollutants. In the present work, we aim to synthesize a single-phase high-entropy zirconate pyrochlore oxide (Ce0.2Pr0.2Zn0.2Nd0.2Tb0.2)2Zr2O7 using a modified Pechini method. The physicochemical properties of the prepared nanoparticles were investigated using X-ray diffraction, UV-visible spectroscopy, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy. The photocatalytic properties were examined using cationic dye (methylene blue), anionic dye (Congo red), and Cr(VI). Photocatalytic degradation experiments demonstrate exceptional efficiency in the removal of persistent organic pollutants. The photocatalytic results indicate that the prepared high-entropy (Ce0.2Pr0.2Zn0.2Nd0.2Tb0.2)2Zr2O7 zirconate pyrochlore oxide could effectively degrade dyes and reduce Cr(VI). Radical trapping experiments indicate that the degradation of dyes was driven by the hydroxyl radicals, superoxide radicals, and holes. Furthermore, the position of the valence band and conduction band promoted efficient photocatalytic reaction kinetics. The prepared photocatalyst remains structurally stable and can be reused three times without losing activity.

Development of environmentally benign methods for CP bond formation is of great significance due to the extensive applications of organophosphorus compounds in pharmaceuticals and agrochemicals. Herein, we report a polyoxovanadate‐based Cu–organic framework, [Cu 3 (pty) 2 ][V 8 O 23 ]·H 2 O ( Cu‐POV , pty = 4′‐(pyridin‐4‐yl)‐2,2′:6′,2″‐terpyridine), for catalyzing the cross‐dehydrogenative coupling of N‐aryl tetrahydroisoquinolines with diarylphosphine oxides to form CP bonds using molecular oxygen (O 2 ) as an oxidant in green ethanol medium. The outstanding efficiency of Cu‐POV stems from a synergistic mechanism involving its structural Cu II and V V centers: the two activate the N‐aryl tetrahydroisoquinolines through single‐electron transfer and subsequently react with O 2 to generate the key superoxide radical species. The catalyst can be recycled at least six times without compromising performance, and applied in gram‐scale reaction with a turnover number of 2025.

The need for new medications to treat diabetes mellitus (DM) is a global health concern due to the cost and impact on patients and their families, health systems, and society. Recent approaches in drug development have focused on multitarget therapy for DM, considering its multifactorial and complex pathophysiology. The present work contributes to the review of the plant species Schinus molle L. (pirul), a tropical tree native to South America but now widespread worldwide, which has demonstrated anticancer, analgesic, antibacterial, and insecticidal properties. According to traditional uses, pirul has been employed as a food condiment, in the preparation of beverages and chewing gums, and in the treatment of DM. The antidiabetic effects of pirul appear to act through several mechanisms involved in DM. The methanolic extract of S. molle fruits collected in Tunisia exhibited a dose-dependent inhibition on both α-amylase and α-glucosidase enzymes (77.49% and 86.45%, respectively). A dose-dependent anti-inflammatory effect was also observed at 1, 2, 3, 4, and 5 h, in the carrageenan-induced rats’ paw edema model. Furthermore, in both the H2O2 and the superoxide radical assays, the pirul extract demonstrated moderate antioxidant activity (IC50 = 0.22 mg/mL). Isomasticadienonic acid and Masazino-flavanone, the major components of active fractions and extracts of S. molle represent promising antidiabetic agents. Although pirul appears to be safe in in vivo acute and subchronic administrations, toxicological studies and clinical trials in individuals with DM are still pending.

Abstract Electrical treeing, manifesting as Lichtenberg figures (LFs) is a major cause of dielectric failure in power, communication, and aerospace systems. Visualization of LF evolution has been hindered by passive imaging limits. Here, we introduce phosphorescence imaging of Lichtenberg figures (PI‐LF), which maps both structural damage and localized oxygen depletion via high‐contrast luminescent signals. Guided by a mechanistic understanding of oxygen metabolism in photoactivated phosphorescent systems, indole‐core dopants with tunable chromaticity reveal dual oxygen pathways: energy transfer to singlet oxygen and electron transfer to superoxide radicals. Polymer systems doped with these luminophores resolve fine structural progression of electrical trees, enabling bioimaging‐style analysis that uncovers a previously hidden spherical‐layered growth mode. PI‐LF bridges molecular photophysics and high‐voltage engineering, establishing a paradigm for luminescence‐based visualization of dielectric breakdown.

BODIPY-based small molecular probes for fluorescence and photoacoustic dual-modality imaging of superoxide anion in vivo.

Efficient PFOA decontamination using photoelectrocatalytic coupled PMS activation: Unleashing electrons and superoxide radicals for rapid degradation.

Synergistic strengthening mechanism of microbial-mediated Fenton system on lignin depolymerization during rice straw composting.

Decoding pyrene-induced reactive oxygen species production in the rhizosphere and their role in biodegradation: The repair mechanism of symbiotic driving by Fe(II) and microorganisms.

Overuse of pesticides often poses a severe threat to agricultural productivity. Invitro experiments were conducted to assess the effect of different concentrations (10, 20, 40, 80, and 100 μg mL-1) of chlorpyrifos (CP) and imidacloprid (IMD) on germination, physiology, and cellular properties of lettuce (Lactuca sativa). The 100 μg mL-1 dose greatly reduced germination attributes, length, and seedling survival. At 100 μg mL-1, CP and IMD decreased seed germination (80% and 60%), vigor indices (76.7% and 65.3%), survival (79.5% and 65.5%), and tolerance indices (83.3% and 62.5%) as compared to control. Insecticide-exposed roots showed cracks/fractures, disintegration, and distortion over control roots, thus exhibiting the toxic potential of insecticides. Elevated CP and IMD concentrations led to increased oxidative stress and the generation of reactive oxygen species (ROS) in lettuce seedlings. When subjected to 100 μg mL-1 of CP and IMD, seedlings exhibited a significant (p ≤ 0.05) increase in levels of hydrogen peroxide (70.2% and 56.8%), superoxide radicals (88.9% and 70.5%), electrolyte leakage (87.9% and 66.4%), and malondialdehyde (94.5% and 61.4%). Furthermore, insecticide dose-dependent declines in adenosine triphosphate (ATP) content and respiration efficiency (RE) were observed in seedlings. Antioxidant enzymes' activity in lettuce was modulated by exogenous insecticide treatments. Secondary metabolites and antioxidant activities were altered in lettuce under insecticide stress. Both insecticides imparted phytotoxic effects that highlight the importance of their optimal utilization in soil-plant systems and their careful monitoring in soils. There is an urgent need to develop slow-release and target-specific pesticide formulations that ensure effective crop protection while safeguarding soil health.

Role of carbon nanotubes in boosting photocatalytic hydrogen production and pollutants degradation within S-Scheme g-C3N4/ZnO nanocomposite.

Green synthesis of biopolymer-driven dual functional carboxymethyl cellulose composite (CMC/MIL100(Fe)/MIL88A(Al)) as a Z-scheme photocatalyst and an adsorbent for water pollutants.

Nanoengineering construction of Fe2O3/g-C3N4 heterojunctions for cooperative enhanced photocatalytic CO2 reduction and pollutant degradation.

Aeration-driven peroxymonosulfate piezoactivation by PVDF-BTO composite membrane for the effective elimination of antibiotic resistance genes.

The photocatalytic degradation of Crystal Violet (CV) using ZnO-based nanomaterials presents a promising solution for addressing water pollution caused by synthetic dyes. This review highlights the exceptional efficiency of ZnO and its modified forms—such as doped, composite, and heterostructured variants—in degrading CV under both ultraviolet (UV) and solar irradiation. Key advancements include strategic bandgap engineering through doping (e.g., Cd, Mn, Co), innovative heterojunction designs (e.g., n-ZnO/p-Cu2O, g-C3N4/ZnO), and composite formations with graphene oxide, which collectively enhance visible-light absorption and minimize charge recombination. The degradation mechanism, primarily driven by hydroxyl and superoxide radicals, leads to the complete mineralization of CV into non-toxic byproducts. Furthermore, this review emphasizes the emerging role of Artificial Neural Networks (ANNs) as superior tools for optimizing degradation parameters, demonstrating higher predictive accuracy and scalability compared to traditional methods like Response Surface Methodology (RSM). Potential operational challenges and future directions—including machine learning-driven optimization, real-effluent testing potential, and the development of solar-active catalysts—are further discussed. This work not only consolidates recent breakthroughs in ZnO-based photocatalysis but also provides a forward-looking perspective on sustainable wastewater treatment strategies.

Engineering oxygen vacancy-enriched S-scheme ZnIO3(OH)/BiOIO3 heterojunction architectures for enhanced charge separation and photocatalytic efficiency.

A NiO-ZnO-MgO ternary heterojunction nanocomposite was synthesized in this work using a microwave-assisted green precipitation approach to improve the photocatalytic removal of methylene blue (MB) dye driven by visible light. Structural analysis via SEM explored round-shaped particles with an average dimension of 14 nm, whereas FTIR established the existence of Zn-O (512 cm-1), Ni-O (564 cm-1), and Mg-O (1399 cm-1) vibrational modes. BET surface analysis demonstrated a high specific surface area of 77.26 m2/g, a pore radius of 15.98 Å, and a pore volume of 0.037 cc/g. Under optimized conditions (pH 9.2, 40°C, visible light intensity of 100 W), the nanocomposite achieved a MB dye degradation efficiency of 90.9% within 120 min, which is superior to many conventional photocatalysts such as TiO2 (15%-30%), ZnO (70%-85%), and binary ZnO-NiO composites (~80%-85%) under similar light exposure conditions. The quantum yield (QY) and space-time yield (STY) were estimated as 7.49 × 10-7 molecules/photon and 6.57 × 10-8 molecules/photon·mg, respectively. Degradation performance was further enhanced by the creation of defect states and reactive oxygen species (ROS), especially superoxide radicals (•O2 -). The NiO-ZnO-MgO nanocomposite's promise as an economical and ecologically friendly photocatalyst for wastewater treatment is shown by these results.

Visible light-activated cobalt phthalocyanine/UiO-67 composite: A novel approach to photodynamic antibacterial therapy.