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.

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.

Mycelium derived from Ganoderma lucidum was employed as a template for synthesising silicon oxide (SiOx) nanofibers. The intricate structures of mycelial hyphae fibrils were replicated with high precision using an inexpensive commercial silane (3-aminopropyl)-triethoxysilane (APTES). Following the removal of the organic mycelium template phase at 600 degrees C, APTES was successfully converted to SiOx. The resulting SiOx fibres retained the morphology of the mycelium template, with a nearly identical fibre density to the original fibrous network. A fibril diameter reduction of approximately 43% was observed from 603 to 344 nm. All synthesised materials exhibited coherent structural integrity, sufficient for handling without breakage, although they were notably less mechanically flexible than the original mycelium template. The novel hybrid mycelium-3-aminopropyl-silsesquioxane fibre network and the thermally converted SiOx network displayed notable liquid absorption properties. These materials allowed for the preferential absorption of oil or water, depending on the presence of the amino group functionality. Remarkably, the SiOx network rapidly absorbed methylene blue-dyed water within 400 ms, demonstrating behaviour opposite to the virgin mycelium network. Additionally, the materials exhibited high thermal stability, withstanding flame exposure at approximately 1400 degrees C while maintaining their nano/micromorphology. This innovative approach of using "living" templates expands the range of morphologies that can be replicated in inorganic materials, enabling the creation of genetically and environmentally tuneable structures. The SiOx nanofibers produced through this method have potential applications in various fields, including water purification, biosensors, catalytic support, and insulation.

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.

A strategy to increase the biobased content and use of side-streams in plastic materials is to mix in biobased fillers available as inexpensive by-products. In line with this, herein, results on a polyolefin polymer with added wood powder (with or without a thermal treatment) and oat husk are presented, to make vacuum-formed products. The composite material is compounded, with or without a coupling agent, and then compression molded into sheets that are subsequently vacuum-formed. Despite a large content of fillers, the surface finish is in general smooth and uniform. The presence of filler increased, in general, the stiffness, and the use of the coupling agent is beneficial for the mechanical properties. The ductility and toughness, decreased in the presence of fillers, but the strain at break remained always larger than 10%. The fillers are all more hygroscopic than the polyolefin, which led to an increase in water uptake in the composites when immersed in water. The largest uptake, but still below 3.5% after 5 weeks, is observed for the material with oat husk. The results are overall promising, and open up for the use of biocomposites derived from industrial side-stream biofillers in vacuum-formed products.

This review focuses on the use of polyolefins in high-voltage direct-current (HVDC) cables and capacitors. A short description of the latest evolution and current use of HVDC cables and capacitors is first provided, followed by the basics of electric insulation and capacitor functions. Methods to determine dielectric properties are described, including charge transport, space charges, resistivity, dielectric loss, and breakdown strength. The semicrystalline structure of polyethylene and isotactic polypropylene is described, and the way it relates to the dielectric properties is discussed. A significant part of the review is devoted to describing the state of art of the modeling and prediction of electric or dielectric properties of polyolefins with consideration of both atomistic and continuum approaches. Furthermore, the effects of the purity of the materials and the presence of nanoparticles are presented, and the review ends with the sustainability aspects of these materials. In summary, the effective use of modeling in combination with experimental work is described as an important route toward understanding and designing the next generations of materials for electrical insulation in high-voltage transmission.

The production of biodegradable gluten-based protein foams showing complete natural degradation in soil after 26 days is reported, as an alternative to commercial foams in disposable sanitary articles that rely on non-biodegradable materials. The foams were developed from an extensive evaluation of different foaming methodologies (oven expansion, compression moulding, and extrusion), resulting in low-density foams (ca. 400 kg/m3) with homogenous pore size distributions. The products showed the ability to absorb 3–4 times their weight, reaching ranges for their use as absorbents in single-use disposable sanitary articles. An additional innovative contribution is that these gluten foams were made from natural and non-toxic wheat protein, glycerol, sodium and ammonium bicarbonate, making them useful as fossil-plastic-free replacements for commercial products without the risk of having micro-plastic and chemical pollution. The impact of different processing conditions on forming the porous biopolymer network is explained, i.e., temperature, pressure, and extensive shear forces, which were also investigated for different pH/chemical conditions. The development of micro-plastic-free foams mitigating environmental pollution and waste while using industrial co-products is fundamental for developing large-scale production of single-use items. A sanitary pad prototype is demonstrated as an eco-friendly material alternative that paves the way for sustainable practices in manufacturing, and contributes to the global effort in combating plastic pollution and waste management challenges, Sustainable Development Goals: 12, 13, 14, and 15.

To broaden the range in structures and properties, and therefore the applicability of sustainable foams based on wheat gluten expanded with ammonium-bicarbonate, we show here how three naturally ocurring multifunctional additives affect their properties. Citric acid yields foams with the lowest density (porosity of ~50%) with mainly closed cells. Gallic acid acts as a radical scavenger, yielding the least crosslinked/ aggregated foam. The use of a low amount of this acid yields foams with the highest uptake of the body-fluid model substance (saline, ~130% after 24 hours). However, foams with genipin show a large and rapid capillary uptake (50% in one second), due to their high content of open cells. The most dense and stiff foam is obtained with one weight percent genipin, which is also the most crosslinked. Overall, the foams show a high energy loss-rate under cyclic compression (84-92% at 50% strain), indicating promising cushioning behaviour. They also show a low compression set, indicating promising sealability. Overall, the work here provides a step towards using protein biofoams as a sustainable alternative to fossil-based plastic/rubber foams in applications where absorbent and/or mechanical properties play a key role.

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.