Research Articles

Wood pellets, which are regarded as a sustainable and nature-friendly energy source, occupy an important place in biomass production, and global pellet production is constantly increasing. Pellet quality varies significantly according to the structural properties of the wood used as raw material, and the wood structure is the most important factor that determines the quality of the pellet. Numerous studies have been conducted on the quality of pellets produced from various raw materials. Although different origins of the same species can significantly affect pellet quality, the study on this subject is very limited. C, O, N and H contents, pH and heavy metal contents of pellets produced from Fagus orientalis wood obtained from 12 different origins were compared. As a result of the study, it was determined that there was a statistically significant difference between the pellets produced from wood obtained from different origins in terms of Cd and Ni concentrations, as well as oxygen, nitrogen, and hydrogen contents. The results indicate that the highest quality pellets among the origins studied were those produced from beeches from the Andırın, Yazıcık, Gökçebey, and Kalkım origins, which had both low heavy metal content and low oxygen, nitrogen, and hydrogen contents. It is proposed that these origins be given priority in pellet production.

The global transition toward environmentally sustainable technologies necessitates the development of biodegradable electrical insulating fluids. This study investigates the performance of a vacuum–fractional distillation reactor designed to convert high free fatty acid (FFA) crude palm oil (CPO) into a biodegradable electrical insulator. The reactor simultaneously performs degumming, deodorization, and vacuum spray drying, thereby enabling efficient purification and moisture removal. Experimental results demonstrated that even at a minimal processing time of 20 min, the breakdown voltage (BDV) exceeded 50 kV with the IEC 60156 (2018) test, with a peak performance of 59 kV at 50 min. The reactor achieved Specific Energy Consumption of 2.1 kWh/L. Thermal analysis indicated that 0.136 kWh was converted into useful heat, resulting in a thermal efficiency of approximately only 4.3%, primarily due to heat losses and irreversibility associated with the uninsulated laboratory-scale configuration, thereby indicating potential for improved heat utilization and energy recovery. The novelty of this work lies in the process integration, enabling treatment of high-FFA CPO in a single system, reducing operational complexity, and enables energy analysis. However, while the breakdown voltage requirement was satisfied, full compliance with IEC 62770 specifications necessitates further physicochemical characterization, which will be explored in future work.

In plants, the transport of water is mediated by vessel and pit structures, which are integral to this physiological process. Among the various pit types, the bordered pit is recognized as particularly effective. To investigate the impact of structural parameters on fluid flow performance, a microstructural fluid dynamics model of plant tissue was developed employing finite element simulation. This model integrates laminar flow and porous media physics within a unified framework, and the computed results agreed with existing experimental and numerical studies. An analysis was conducted to assess variations in pressure drop, flow rate, and flow resistance as a function of several parameters, including pit aperture diameter, torus diameter, pit diameter, pit depth, margo thickness, porosity, and micropore diameter. The results demonstrate that overall flow resistance decreases with increases in pit diameter, pit aperture diameter, pit depth, porosity, and micropore diameter, whereas it increases with larger torus diameter and margo thickness. Notably, parameters associated with the margo exert a particularly pronounced effect on water transport characteristics. This study provides a mechanical rationale elucidating the structure-function relationship governing water transport in coniferous plants and offers theoretical foundations for the design of biomimetic microfluidic devices and plant-inspired water-conducting materials.

The impact of drought and Pb toxicity were evaluated relative to physiological and biochemical traits of four commonly used urban tree species. The experiment included six treatments: control, 300 ppm Pb, 600 ppm Pb, drought (50% field capacity), drought + 300 ppm Pb, and drought + 600 ppm Pb, applied to Platanus orientalis, Fraxinus excelsior, Cupressus sempervirens, and Pinus nigra. Results showed that Pb toxicity – particularly 600 ppm and drought – led to changes in most traits of the plants (P ≤ 0.05). The co-applied drought and 600 ppm Pb decreased total chlorophyll (Chl, 21%), relative water content (RWC, 23%), while increased malondialdehyde (MDA, 52%), proline accumulation (22%), total soluble sugar (TSS, 54%), superoxide dismutase (SOD, 110%), catalase activity (CAT, 137%), Pb accumulation in roots (1723%), and in shoots (611%) compared to the control. Compared to C. sempervirens and P. nigra, P. orientalis and F. excelsior accumulated more Pb and exhibited greater sensitivity to abiotic stress. The heat map results exhibited that traits under drought and Pb stress showed the most significant fluctuation, with TSS explaining the most variation among measured traits.

Hydrogels based on TEMPO-oxidized cellulose nanofibrils (TOCNF) are attractive sustainable materials but often suffer from poor structural stability and weak mechanical strength. In this study, surface-deacetylated chitin nanofibrils (ChNF) were incorporated to reinforce TOCNF hydrogels, and the effect of hydrothermal treatment on network structure and properties was investigated. Hydrogels were prepared at solid contents of 1.25 to 2.00 wt% by mixing dilute TOCNF and ChNF suspensions followed by centrifugation and hydrothermal treatment. Compared with TOCNF alone, TOCNF/ChNF hydrogels exhibited improved shape stability, higher viscosity, and enhanced shear-thinning behavior. Hydrothermally treated TOCNF/ChNF hydrogels maintained elastic behavior up to 74.6% strain, compared with 26.3% strain for non-treated TOCNF/ChNF hydrogels. The compressive strength increased markedly, reaching 36 kPa at 1.75 wt%, whereas TOCNF hydrogels showed only ~5 kPa. FTIR and XPS analyses indicated redistribution of intermolecular interactions after hydrothermal treatment without definitive evidence of covalent bond formation. SEM observations further revealed the formation of a more interconnected and densified porous network after hydrothermal treatment. Overall, ChNF reinforcement combined with hydrothermal treatment effectively improved the structural stability and mechanical performance of TOCNF hydrogels.

This study investigated the potential of dry processing methods to manufacture bio-based materials with reduced environmental impacts, which is in alignment with the energetic and ecological transitions global strategies. The increasing demand for eco-friendly materials drives research into bio-based composites. The mechanical properties were evaluated for binderless composites made from walnut shells, which are industrial bio-based by-products. Thermocompression moulding was used to fabricate the composites. Their mechanical behaviour and their resistance to water were tested. The composites showed a flexural strength of 16.9 MPa and a Young’s modulus of 4.3 GPa. These findings suggest that walnut shell-based composites are viable alternatives for sustainable materials.

Lignocellulosic biomass is a widely available renewable resource, yet its recalcitrant structure limits enzymatic hydrolysis and bioethanol production. This study aimed to develop an efficient pretreatment method for pine wood chips by integrating steam explosion with potassium hydroxide (KOH) treatment and to explore the reuse potential of the resulting liquid waste. Steam explosion disrupted chip structure and exposed cellulose, while subsequent KOH pretreatment selectively removed lignin and hemicellulose, thereby enhancing enzymatic accessibility. Response surface methodology identified optimal conditions of 2.9 min steam explosion, 1.4% KOH, and 21 h treatment time, which yielded a maximum glucose conversion of 30% (based on raw material). The combined process increased ethanol production, with yields approximately sevenfold higher than untreated controls. In addition, liquid waste containing potassium elements promoted the growth of red lettuce, perilla, and green onion, with perilla showing a fivefold increase in fresh weight compared to controls. These findings demonstrate that steam explosion coupled with KOH pretreatment not only improves the efficiency of bioethanol production but also offers a sustainable route for recycling liquid residues as agricultural fertilizer.

N,P co-doped porous carbon (NPPC) was prepared as a high-performance electrode material for supercapacitors. NPPC materials were synthesized through a facile single-batch carbonization-activation strategy. Poria cocos residue was used as a renewable biomass precursor, potassium carbonate as the chemical activator, and melamine phosphate served as the dual N/P doping agent. A Box-Behnken design  in response surface methodology was utilized to optimize three critical process parameters: K₂CO₃ ratio, N,P co-doped ratio, and activation temperature, aiming at maximizing the specific capacitance. The morphological, structural, and electrochemical properties of the prepared carbon materials were systematically characterized by scanning electron microscopy, N₂ adsorption–desorption  isotherms, X-ray photoelectron spectroscopy, cyclic voltammetry, galvanostatic charge-discharge technique, and electrochemical impedance spectroscopy. The optimized NPPC exhibited hierarchical porous structure with a high specific surface area (reaching 2980 m²⋅g⁻¹), uniformly distributed N (12.3 at.%) and P (0.59 at.%) heteroatoms, and excellent supercapacitive performance. It achieved a maximum specific capacitance of 332 F⋅g⁻¹ at a current density of 1 A⋅g⁻¹ in a 6 M KOH electrolyte. This work realizes the high-value valorization of TCM solid waste and provides a green, cost-effective, and scalable route for the synthesis of high-performance supercapacitor electrode materials, aligning with the goals of waste recycling and carbon neutrality.

The spathe of the date palm Phoenix dactylifera (L.) is a lignocellulosic agricultural by-product that can be exploited as a source of biomass for high value products. However, limited information is available regarding the toxicological safety of its extracts. This study aimed to evaluate the in vivo toxicity of date palm spathe extracts through acute and subacute oral tests in mice to support their potential valorization. In the acute test, female mice were treated with single oral doses of 300 and 2000 mg/kg for 14 days. For the subacute test, daily doses of 50, 300, and 1000 mg/kg were administered to both sexes for 28 days. In both studies, clinical symptoms, mortality, body weight variations, organ weights, biochemical and hematological criteria, and histopathological analyses were examined. No lethality or significant clinical signs were observed at any of the tested doses. Hematological and biochemical parameters showed no significant changes between groups. Histopathological examination of the organs showed similar results in both the acute and subacute phases, represented by mild, non-specific changes compatible with background lesions in mice. These findings indicate a favorable toxicological safety profile, supporting the potential valorization of date palm spathe extracts.

The shrub Ricinus communis, originally from Asia, has adapted to different regions of Mexico. The main value of this crop lies in the production of non-edible vegetable oil. In this work, extracts from the leaves of R. communis were obtained using various solvents: methanol, ethanol, and water; as well as 80:20 mixtures of methanol:water and ethanol:water. The extraction yield ranged between 1.00 and 2.10 g of extract per 100 g of plant material. The aqueous extract showed the highest yield, while the methanol: water mixture had the lowest. A SEM-EDS analysis was applied to the leaves before and after the extraction. The extracts were tested as antioxidants through free radical scavenging assays, ferric reducing capacity, and total phenolic content. The extract that exhibited the highest IC₅₀ value was the water, followed by ethanol, with values of 38.94 and 331.01, respectively. The extract from the leaves of R. communis, demonstrated antioxidant properties. This suggests that this biomass can serve as a source of natural antioxidants, thus utilizing this by product of the crop. The SEM-EDS results indicate that the leaves were not contaminated with metals or other sources, supporting the use of these extracts in applications such as biodiesel.