Lignin electrolysis has emerged as an innovative and sustainable energy technology capable of producing “green hydrogen,” representing a more energy-efficient alternative to conventional water electrolysis [1–3]. Hydrogen, owing to its high energy density, clean combustion, and environmentally friendly nature, is considered a key energy vector to accelerate the transition away from fossil fuels [2,3]. However, traditional water electrolysis is often limited by high energy requirements and sluggish oxygen evolution kinetics, motivating the development of alternative strategies. In this study, lignin, a major component of biomass and an abundant renewable carbon source, was employed as an anodic feedstock to replace water oxidation. This approach not only reduces the overall energy demand but also simultaneously enables the valorization of lignin into value-added aromatic compounds.

To enhance catalytic efficiency, the catalysts were strategically engineered through structural tailoring to achieve a high surface area, abundant defects, and enriched oxygenated functional groups [4–6]. In particular, carbon-based catalysts with oxygenated acid sites demonstrated remarkable activity and stability in lignin electrolysis, facilitating efficient hydrogen generation at the cathode while promoting selective oxidation of lignin at the anode. As a result, this novel process yields pure hydrogen with reduced energy input and valuable organic by-products such as vanillin, thereby coupling green hydrogen production with biomass-waste valorization [3,8,10].

These findings highlight the dual benefit of lignin electrolysis: advancing renewable hydrogen production while providing a sustainable route for the circular use of biomass resources. This work underscores the potential of functional carbon-based catalysts as a versatile platform for clean energy and green chemistry applications.

Recycling polyolefins remains a significant challenge in advancing polymer sustainability due to their chemical inertness and inherent immiscibility in mixed polymer systems. In this study, a circular strategy is presented in which degraded polypropylene (PP) is transformed into a functional compatibilizer for polypropylene/polyethylene (PP/PE) blends, providing a value-added approach to polyolefin upcycling. Successive melt extrusion of PP in the presence of montmorillonite (MMT) and metal-modified MMT promoted extensive chain scission and oxidative degradation, generating oxygen-rich, low-molecular-weight fragments. Thermal analysis using TGA and DSC highlighted the efficiency of multiple processing cycles in modifying the polymer structure, and also highlighted the role of MMT as a stabilizing agent. The degraded fragments were subsequently recovered via solvent extraction, and detailed characterization using FTIR, NMR, TGA, and GC–MS confirmed the presence of carbonyl, hydroxyl, and ester functional groups. These functionalized oligomeric fragments were evaluated as compatibilizers in PP/PE blends, demonstrating their ability to improve interfacial adhesion and dispersion, thereby linking controlled polymer degradation to the creation of functional additives. Overall, this work establishes a closed-loop upcycling pathway in which the by-products of PP degradation are valorized as compatibilizers, offering a sustainable approach for the management of polyolefin waste and contributing to the development of circular polymer materials.

Industrial wastewater containing dye pollutants poses significant environmental challenges, necessitating advanced treatment technologies. This study presents the development and optimization of a novel PVDF/MgO mixed matrix membrane incorporating green-synthesized magnesium oxide nanoparticles using Arbutus unedo leaf extract for sustainable dye removal from aqueous solutions. The membrane's performance for Bemacid Turquoise dye removal was systematically optimized using three complementary approaches: Response Surface Methodology (RSM), artificial neural networks (ANN), and SOLVER algorithms. Comprehensive characterization was performed using X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy, mechanical testing, and contact angle measurements. The optimum conditions were achieved with a membrane composition of 0.6 %, a temperature of 40 °C, and an initial dye concentration of 100 mg. L^-1. Comparative analysis revealed superior predictive accuracy of the ANN model over RSM, evidenced by lower mean squared error (MSE), mean absolute error (MAE), and root mean squared error (RMSE) values, coupled with higher R² correlation. SOLVER optimization further refined the parameters, achieving maximum Bemacid Turquoise removal at 94.08 mg/L initial concentration, 0.51 % membrane composition, and 50.12 °C temperature. The results demonstrate the exceptional potential of this eco-friendly PVDF/MgO membrane system as a sustainable and effective solution for industrial wastewater treatment, combining green synthesis principles with advanced optimization methodologies.

Fluoride contamination in drinking water is a global challenge due to its adverse health effects, including dental and skeletal fluorosis. The limitations of conventional removal methods, such as chemical precipitation and ion exchange, drive the search for sustainable and low-cost adsorbents. Coffee grounds, an abundant agro-industrial residue rich in carbon, show great potential as a precursor for activated carbon. Surface modification with citric acid, including its natural source from lemon juice, can significantly enhance adsorption capacity and provide a low-cost process accessible to rural communities, thereby promoting self-sufficiency in safe water treatment locally.

In this study, activated carbons derived from coffee grounds were prepared under different activation conditions (non-activated, CO₂-activated, and H₃PO₄-activated) and subsequently impregnated with citric acid or lemon extract. Adsorption experiments using sodium fluoride solutions were conducted to evaluate performance. CO₂-activated carbon impregnated with citric acid exhibited the highest adsorption capacity, reaching 0.16 mg g⁻¹ after 6 hours of contact.

The results demonstrate that agro-industrial residues, when converted into functional adsorbents, can provide viable, sustainable, and low-cost alternatives for fluoride removal in drinking water. This innovative approach reinforces the role of circular economy strategies and technological innovation in decentralized sanitation, particularly in vulnerable rural communities lacking access to conventional solutions.

Sachet water has been identified in recent years as the most common means of water packaging in West Africa, particularly Ghana. The water is packaged in 500ml heat-sealed Low-Density Polyethylene (LDPE) plastic bags, popularly known in the streets as “pure water” and is considered safe and hygienic for consumption. Sachet water after being consumed, however, is not properly disposed of, causing adverse environmental issues.

This study talks about the effect of improper disposal of the plastic packaging material, with the aim of combining the waste water sachet with pineapple leaf fibres to produce a composite material. The procedure through which the raw materials were obtained and how the composite was made are stated. Impact and breakdown voltage tests were performed on the material obtained, and the results were evaluated. The impact test results showed a decrease in impact strength as the fibre content was increased. This was attributed to the incomplete bond or adherence of the matrix to the fibre. The results obtained for the breakdown voltage test also showed an overall decrease in breakdown voltage values as compared to the value obtained for pure LDPE. Specimens with 15% fibre content had the highest value among the samples containing fibres. The values obtained were attributed to the presence of voids in the composite material.

Environmental pollution has emerged as a critical global concern due to the release of pollutants from industries, agricultural fields, and other human activities, requiring urgent attention and sustainable solutions. Metal–Organic Frameworks (MOFs) are porous materials consisting of organic ligands and inorganic metal ions or clusters. They have been introduced as a promising class of material for environmental remediation. Their variable pore size, large surface area, and diverse structural and functional properties make them suitable for environmental applications. Water purification through the removal of heavy metals, dyes, toxins, and organic pollutants have been achieved through these materials. The removal of harmful gases (carbon dioxide, sulphur dioxide, ammonia) from the environment is another important application of MOFs. This paper gives a critical insight into the mechanistic pathways of MOFs in adsorption, photocatalysis, redox-mediated degradation, and ion-exchange processes used for the removal of pollutants. The structural features of MOFs influence contaminant capture, selectivity, and degradation kinetics. Recent studies employing in situ spectroscopy, computational modeling, and kinetic analysis have unraveled the interaction dynamics between MOFs and pollutants. By bridging structural attributes with mechanistic functions, this paper will be helpful in the further exploration of MOFs, with potential to restore the environment.

The transition to sustainable manufacturing is driving the increased use of recycled aluminium alloys. However, the variability of residual elements such as Mg, Fe, or Mn poses challenges for achieving reliable microstructural control and mechanical performance. This study investigated the influence of Mg and Mn content on the microstructure and properties of recycled Al-Si alloys. Alloys with varying Mg concentrations (0.2 to 0.5 wt.%) and Mn additions (0.07 to 0.54 wt.‰), representative of recycled feedstock compositions, were prepared by casting. Microstructure analysis revealed that increasing Mg promoted Mg₂Si formation, and also modified the morphology and distribution of intermetallic phases. Mechanical testing showed that increasing Mg from 0.2 to 0.5 wt.% enhanced strength through precipitation and solid solution strengthening while reducing ductility; the yield strength increased from 156 to 250 MPa and the ultimate tensile strength from 242 to 296 MPa, whereas ductility decreased from 7.8 to 2.9 %. Addition of 0.54 wt.‰ Mn did not show a significant effect on strength or ductility in the compositions evaluated. The results highlight the critical role of Mg in recycled aluminium alloys, demonstrating both its strengthening potential and its risk of embrittlement as a function of its composition. The findings provide a pathway for alloy design and process optimisation to enable high-value use of recycled Al alloys in structural applications, supporting a more sustainable circular economy in the aluminium sector.

The use of reclaimed asphalt pavement (RAP) in hot-mix asphalt (HMA) has grown as transportation agencies seek to reduce costs and limit landfill waste. Working with RAP allows for the reuse of the aggregate and its asphalt coating, reducing waste. The asphalt coating needed for HMA is largely found on the finer aggregates, resulting in a dominantly finer graded mixture, reducing its compressive strength and increasing its susceptibility to rutting. Recycled asphalt shingles (RAS) have around five times the asphalt content found on fine RAP aggregate, which can offset this issue by supplying an alternative asphalt binder, allowing for more coarse aggregate to be introduced, improving overall pavement performance and durability.

This study investigates the feasibility of incorporating RAS into high-RAP mixtures, reducing dependence on fine RAP binder. The control is a 100% RAP HMA with a baseline gradation of 60% fine aggregate and 40% coarse aggregate. A 5% RAS dosage by total mix weight was added based on manufacturer recommendations. Subsequent designs adjust the fine-to-coarse ratio while holding RAS constant to identify mixtures that meet or surpass the control’s performance. The performance was assessed through the IDEAL-CT test (ASTM D8225) for cracking tolerance and the HT-IDT test (ASTM D6931) for indirect tensile strength (ITS), benchmarked against NYSDOT thresholds of CT index ≥ 135 and ITS ≥ 35 psi.

Incorporating RAS improved the CT index by up to 6% and increased ITS as much as 15%. A mix containing 5% RAS, 35% RAP sand, and 60% RAP stone satisfied the ASTM D6931 strength requirement but didn’t consistently achieve the ASTM D8225 cracking criterion. The shortfall in the CT index values is believed to come from an underestimation of the RAS performance grade (PG), resulting in the mixture being stiffer than expected.

Hexagonal ferrites, particularly strontium ferrite (SrFe₁₂O₁₉), are among the most promising candidates for the partial substitution of rare-earth-based permanent magnets. While they have been successfully implemented in various applications, the fabrication of dense SrFe₁₂O₁₉ components with optimal magnetic properties remains a major challenge. Conventional sintering techniques often require prolonged high-temperature treatments, leading to significant grain growth and consequent deterioration of coercivity—an essential property for magnet performance.

In this study, we explore the use of advanced flash sintering techniques to overcome these limitations. Flash sintering, a rapidly growing field within the FAST (Field-Assisted Sintering Technology) family, enables dramatic reductions in processing time and temperature, offering a more sustainable route for ceramic fabrication. We report on the successful synthesis of SrFe₁₂O₁₉ using three distinct flash-based methods: reactive flash sintering (1), multiphase-reactive flash sintering (2), and touch-free flash sintering (3). These approaches not only improve densification kinetics but also help retain fine microstructures that are critical for high coercivity.

Our results highlight the strong potential of flash techniques for scalable, energy-efficient production of high-performance SrFe₁₂O₁₉ magnets, paving the way for broader industrial adoption of rare-earth-free magnetic materials.

References

[1] A.F. Manchón-Gordón et al. Reactive flash Sintering of SrFe12O19 ceramic permanent magnets, Journal of Alloys and Compounds 922 (2022) 166203.

[2] A.F. Manchón et al. Expanding the scope of multiphase-flash Sintering: Multi-dogbone configurations and reactive processes. Ceramic International 50 (2024) 25210-25215

[3] Syed I.A. Jalali, et al. Touch-free reactive flash sintering of dense strontium hexaferrite permanent magnet Journal of the American Ceramic Society 106 (2023) 7202-7208

In the present research, a general model for the description of the microstructural evolution of metallic systems is presented, which can examine the process without direct measurements and without requiring complex sample preparations. An existing challenge in the field of microstructural studies is to determine the strain dependence of the coefficient in the Taylor and Tabor theories used for the calculation of stress from dislocation densities and hardness values. The parameter describing the geometrical factor in the Taylor equation is analysed as a function of the mean free path. From the measured hardness values, the dislocation densities and characteristic structural size are determined by existing models, in which the general dependence is described by the Sahoo stress model. The dislocation density values are compared with Kocks–Mecking–Estrin and Kubin–Estrin models, and a correlation is found between the coefficients of the various models. The model also calculates the deformation energy.

The structural model is validated by Vickers hardness indentations made on plates with three different chemical compositions from alloy series of Al-1xxx, 5xxx and 6xxx. Based on the results, the applicability can be extended to a wide range of different alloys. The model can be supported by numerical results from the literature on pure aluminum, copper, nickel, iron, chromium, niobium, and aluminum alloys.

This research is supported by the EKÖP-25 University Excellence Scholarship Program of the Ministry for Culture and Innovation from the source of the National Research, Development, and Innovation Fund.

Project no. TKP2021-NVA-29 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NVA funding scheme.