This study reports a green, one-pot synthesis of biofunctionalized iron-oxide nanoparticles (Fe3O4/γ-Fe2O3) using Lagerstroemia indica leaf extract as a combined reducing/capping system. X-ray diffraction confirms mixed magnetite/maghemite phases, while UV–Vis and FTIR support phytochemical surface passivation. SEM-EDX shows agglomerated nanoscale domains enriched in Fe and O; DLS and ζ-potential indicate colloidal stabilization by plant-derived polyphenols. Antioxidant activity quantified by DPPH, ABTS, and total antioxidant capacity increases with dose, achieving up to 92.9% DPPH scavenging at 200 μg ml−1. Potentiodynamic polarization and electrochemical impedance spectroscopy in 0.5 M HCl demonstrate mixed-type inhibition with maximum efficiency of ∼75% at 200 mg l−1, attributed to synergistic adsorption of phytochemical shells and mixed-valence Fe centers that impede charge transfer. The aqueous, additive-lean process furnishes multifunctional nanomaterials with practical antioxidant and corrosion-protection performance

The development of multifunctional nanomaterials provides new opportunities to address both environmental and biomedical challenges. In this study, SnO2 nanoparticles were synthesized using Foeniculum vulgare seed extract and subsequently incorporated into independently synthesized polypyrrole (APS-mediated oxidative polymerization) to obtain PPy-SnO2 nanocomposites. Comprehensive structural, optical and morphological analyses, including FTIR, UV-Vis spectrophotometry, XRD, SEM-EDS, HRTEM, DLS, zeta potential, and BET, confirmed the successful formation of the nanocomposites and the uniform incorporation of SnO2 within the PPy matrix. The PPy-SnO2 nanocomposites demonstrated significant adsorption performance for crystal violet, achieving 92% removal under optimized conditions, including pH 7, a dye concentration of 10 ppm, 50 mg adsorbent, and 50 °C for 150 min. Adsorption behaviour followed a pseudo-2nd-order kinetic model, and a maximum capacity of 162.6 mg g−1 estimated from the Langmuir isotherm was achieved. The antioxidant activity assessed by DPPH and ABTS assays in methanol and hexane showed higher radical scavenging efficiency in methanol, achieving 90.8% inhibition at 800 µg mL−1. PPy-SnO2 consistently outperformed pure polypyrrole, indicating the significant role of SnO2 in enhancing electron-transfer-based scavenging. Overall, these results highlight the PPy-SnO2 NCs as an effective dual-application material that combine strong antioxidant properties with high-efficiency dye removal to provide a sustainable approach for environmental remediation.

This study presents an innovative approach to the recovery of nickel from industrial wastewater using cost-effective carbon fiber electrodes, aiming to provide a sustainable and scalable solution for industrial effluent management. Carbon fibers offer unique benefits in electrochemical recovery processes due to their high surface area, excellent conductivity, mechanical durability, and compatibility with low-cost production. The optimized conditions, including a deposition potential of 4 V, pH 3.5, and temperature of 60 degrees C, achieved a high nickel recovery efficiency of 90%, with minimal energy consumption at 3 kW h per kilogram of nickel. This efficiency was verified through Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analyses, which revealed uniform and dense nickel coatings on the carbon fibers, even under continuous operation. Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD) confirmed successful nickel deposition and modifications to the carbon fiber surface chemistry, enhancing the adsorption and reduction of nickel ions. Using carbon fiber electrodes in this process addresses several limitations in traditional electrode materials by reducing costs, improving scalability, and supporting continuous, large-scale nickel recovery. This method offers a viable alternative to conventional electrochemical metal recovery and contributes to circular resource utilization by recycling valuable metals from wastewater. With regulatory pressures increasing around heavy metal discharge limits, this carbon fiber-based electrodeposition process presents a highly promising solution for industrial wastewater treatment, combining environmental sustainability with economic feasibility.

This study presents an eco-friendly approach for synthesizing iron oxide nanoparticles using an extract from Argemone mexicana leaves, which function as reducing and stabilizing agents. The nanoparticles were thoroughly characterized using a range of techniques, including ultraviolet-visible (UV-vis) spectrophotometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and zeta potential analysis. The synthesized Fe-NPs demonstrated notable antioxidant activity, as confirmed by assays involving 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH). The results highlight the significant antioxidant potential of these Fe-NPs. This research introduces a sustainable and innovative synthesis method for Fe-NPs, emphasizing their promising applications, particularly in fields related to antioxidant properties, as evidenced by the conducted antioxidant assays.

The study demonstrates a scalable and reproducible method for synthesising graphene oxide (GO) nanosheets from commercial carbon fibres derived from carbonised polyacrylonitrile (PAN) polymer. An exfoliation route with nitric acid allows for the preparation of monolayer GO nanosheets with a consistent thickness of 0.9 ± 0.2 nm, identical to the commercially available GO from mined graphite. The GO nanosheets exhibit distinct circular and elliptical shapes, in contrast to the polygonal and sharp-edged morphology of commercial GO. An extensive evaluation of acidic solutions and electrical potentials identified a narrow processing window critical for obtaining GO nanosheets sized 0.1–1 µm. An unexpectedly low 5% acid concentration was found to be the most effective, providing a balance between efficient exfoliation through synergistic acidic and electrochemical oxidation. The process provides a high yield of 200 mg of GO per gram of carbon fibre. Advanced characterisation using high-resolution electron and atomic force microscopy (HR-TEM/SEM/AFM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and infrared spectroscopy (FTIR) provided detailed insights into the morphology, thickness, surface functionalisation, and chemical composition of the nanosheets. With its high yield, environmentally sound production, and versatility, the synthesised GO offers transformative potential for large-scale applications, including energy storage, advanced coatings, high-performance composites, water purification, and electronic devices.

This study introduces a green and sustainable method for synthesizing silver oxide nanoparticles (Ag2O NPs) using Lobularia maritima extract as a natural reducing and stabilizing agent. Unlike traditional chemical and physical methods that rely on toxic reagents and high energy inputs, this eco-friendly approach is cost-effective, safer, and aligns with green chemistry principles. The synthesized Ag2O NPs exhibited impressive antioxidant activity, with 80 ± 0.02% 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 75 ± 0.02% 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging efficiencies, comparable to those of ascorbic and gallic acids. In photocatalytic tests, they achieved 91% degradation of methylene blue under visible light within 120 min, outperforming many chemically synthesized Ag2O NPs. Characterization via ultraviolet-visible (UV–vis) spectroscopy, Fourier transform infrared (FTIR), scanning electron microscopy with energy dispersive x-ray analysis (SEM-EDX), dynamic light scattering (DLS), and x-ray diffraction (XRD) confirmed the high purity, stability, and controlled morphology of the samples. These findings highlight the potential of plant-based Ag2O NPs for real-world applications in environmental cleanup and biomedical fields. Future research can focus on scaling production and testing biocompatibility for broader industrial use.

This study presents the synthesis of polyaniline-coated silver (PANI-Ag) nanocomposites via in situ oxidative polymerization and their application in the removal of piracetam, an anti-Alzheimer drug, from aqueous solutions. The nanocomposites were characterized using XRD, FTIR, SEM-EDX, DLS, UV-Vis, and HRTEM. Adsorption experiments optimized key parameters, including pH (7), drug concentration (800 ppm), contact time (180 min), and temperature (65 °C), achieving a 99% removal efficacy. Kinetic and isotherm studies confirmed a Langmuir monolayer adsorption model with pseudo-second-order kinetics, indicating chemisorption. Additionally, the antioxidant activity of PANI-Ag nanocomposites was evaluated using DPPH (56.42%) and ABTS (76.43%) assays, demonstrating superior free radical scavenging compared to PANI alone. These findings highlight the dual potential of PANI-Ag nanocomposites as efficient drug removal agents and antioxidant materials, offering promising applications in environmental remediation and biomedical fields.

An eco-friendly approach to nanocellulose extraction from coconut husk waste is presented, utilizing natural lemon juice for acid hydrolysis instead of conventional sulfuric acid. This environmentally benign method reduces cost and safety concerns associated with chemical processing while offering a sustainable alternative to petroleum-derived acids. Coconut husk, a widely available agricultural waste, poses environmental hazards due to landfill overflow, contributing to pest proliferation and disease outbreaks. In this study, cellulose nanofibrils (CNFs) extracted using lemon juice were characterized by Fourier-Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), and zeta potential analysis. The FTIR spectra confirmed the effective removal of hemicelluloses and lignin, while XRD analysis revealed a crystallinity index of 37%, indicating successful nanofibril isolation. SEM imaging demonstrated the fibrillar morphology of the extracted CNFs, while zeta potential measurements confirmed their colloidal stability. Compared to sulfuric acid-derived CNFs, the lemon juice-extracted nanofibrils exhibited comparable physicochemical properties, validating this green alternative. The findings support sustainable waste management and circular economy principles by promoting the valorization of agricultural residues into high-value nanocellulose. Potential applications include its use as a reinforcement material in biodegradable packaging, biomedical scaffolds, and environmentally friendly nanocomposites. This study aligns with several United Nations Sustainable Development Goals (SDGs), particularly those related to responsible production, sustainable consumption, and reduced dependency on fossil-based resources.

In glucose biofuel cells (G-BFCs), glucose oxidation at the anode and oxygen reduction at the cathode yield electrons, which generate electric energy that can power a wide range of electronic devices. Research associated with the development of G-BFCs has increased in popularity among researchers because of the eco-friendly nature of G-BFCs (as related to their construction) and their evolution from inexpensive bio-based materials. In addition, their excellent specificity towards glucose as an energy source, and other properties, such as small size and weight, make them attractive within various demanding applied environments. For example, G-BFCs have received much attention as implanted devices, especially for uses related to cardiac activities. Envisioned pacemakers and defibrillators powered by G-BFCs would not be required to have conventional lithium batteries exchanged every 5–10 years. However, future research is needed to develop G-BFCs demonstrating more stable power consistency and improved lifespan, as well as solving the challenges in converting laboratory-made implantable G-BFCs into implanted devices in the human body. The categorization of G-BFCs as a subcategory of different biofuel cells and their performance is reviewed in this article.

This review explores the synthesis, characterization, and diverse applications of polyaniline (PANI)-based nanocomposites. PANI, known for its tunable electrical conductivity, eco-stability, and cost-effectiveness, has gained significant attention in advanced materials. This study focused on various preparation techniques, such as chemical oxidative polymerization, electrochemical polymerization, and vapor phase polymerization, highlighting their unique characteristics and impacts on nanocomposite performance. Critical applications of PANI nanocomposites are examined, including their roles in supercapacitors, sensors, solar cells, anticorrosion devices, water purification, and catalysis. Integrating PANI with metals, metal oxides, graphene, and carbon nanostructures enhances its functionality, making it a versatile candidate for innovative technological solutions. This review also addresses the challenges in commercializing PANI nanocomposites and proposes future research directions to overcome these obstacles.