Biomass Conversion and Biorefinery最新文献

The objective of this research is to explore the fatigue, creep, flammability, and thermal conductivity performance of a polyester bio-composite developed using cellulose extracted from jackfruit seed husk and pineapple leaf fibre. The fabrication of the composite involves mixing the jackfruit husk cellulose with the matrix and employing the hand layup technique. Both the cellulose and fibre undergo silane treatment to enhance the composite’s strength. The study conducts a comprehensive characterisation of the composite material following ASTM standards. The findings indicate that the composite labelled PC2, with a 2 vol.% filler addition, exhibits the highest fatigue life counts of 25,860, 21,446, and 16,530 for 25%, 50%, and 75% of the ultimate tensile strength (UTS), along with minimal creep strain values of 0.0326, 0.036, 0.039, 0.041, and 0.045 over time intervals of 2000s, 4000 s, 6000 s, 8000 s, and 10,000 s. Additionally, scanning electron microscopy (SEM) images reveal enhanced bonding between reinforcements and the matrix. Despite a slight impact on flame resistance, the addition of cellulose maintains a V-0 flame rating. Furthermore, the composite designation PC3, containing 4 vol. % cellulose, records the highest thermal conductivity at 0.192 W/mK. These time-dependent property improvements suggest that the developed composites could find applications in various industries, including automotive, aviation, defence, household appliances, and the space sector.

The current study aims to investigate the application of environmentally friendly fiber surface treatment as a means of reducing the environmental risks associated with traditional chemical treatments. Kenaf fibers’ surface was modified with a (10% (w: v)) aqueous solution of sodium bicarbonate, before being included into epoxy matrix to develop kenaf fiber-based epoxy composites. The duration of the kenaf fiber treatment was 24, 48, 72, and 120 h. It was explored and optimized how the sodium bicarbonate treatment affected the developed composite’s tensile, flexural, and thermal properties. There was no significant effect of sodium bicarbonate treatment on the thermal behavior of the developed composites. The developed composites’ tensile and flexural behavior improved most when the fiber was treated for a full 72 h. The tensile and flexural strength of the epoxy composites comprising treated (72-h) kenaf fibers was found to be 33.31% and 25.55% greater than that of the untreated kenaf epoxy composites. Longer treatment times beyond 72 h resulted in reduced mechanical properties due to fiber fibrillation. The morphological behavior of the developed composites revealed fiber pullout, matrix cracks, pits, void development, and the interfacial bond between the epoxy and kenaf fibers. The results showed that the treated fibers bonded well with the epoxy matrix at the interface, which was supported by morphological investigations. The developed composites have the potential to be used in the production of automobile panels and other lightweight industrial items.

In this research, discarded butternut peels were converted into hydrochar products through hydrothermal carbonisation (HTC), with adjustments made to the temperature (ranging from 180 to 260℃) and residence time (spanning 45–180 min). The findings indicated that both the temperature and time of carbonisation significantly influenced the yield of hydrochar (HC), as well as its physiochemical and structural properties. Higher temperatures and prolonged residence time led to decreased yield, elevated fixed carbon content and an increased fuel ratio. Furthermore, raising the process conditions increased HHV and reduced the oxygen-containing functional groups. The HC yield dropped from 28.75 to 17.58% with increased carbonisation temperature and time. The findings of this study also suggest that modified hydrochar is a promising material for removing heavy metals from wastewater. It is a relatively low-cost and abundant material that can be produced from various biomass feedstocks, including food waste. In addition, it is a sustainable and environmentally friendly option for wastewater treatment. Hydrochar-based systems offer several advantages over traditional methods of heavy metal removal, such as chemical precipitation and ion exchange. The unique physicochemical characteristics of hydrochar, including its porous structure and oxygen-rich functional groups, offer a high surface area and more binding sites for heavy metal ions. By changing the physicochemical properties of hydrochar with chemicals like phosphoric acid, it is possible to increase its adsorption capacity. The Freundlich isotherm was the best fit for the adsorption data for all three metal ions (Pb²⁺, Cu²⁺ and Cd²⁺), indicating that the adsorption process is multilayer and heterogeneous.

Pomegranate (Punica granatum) belongs to the Punicacea family and is usually known for its bioactive and potential health-promoting properties. Bioactive compounds are secondary metabolites derived from plants that contribute to health-promoting factors. Due to its natural health-enhancing properties, it has been popularly utilized in the nutraceutical and functional food industry. Numerous studies have demonstrated the abundance of bioactive chemicals in pomegranate peel. Various extraction methods are employed to separate bioactive compounds from plant material and serve multiple purposes. Prolonged extraction methods result in the loss of polyphenols by ionization, hydrolysis, and oxidation. Emerging technologies such as high hydrostatic pressure, ultrasound-assisted, pulsed electric field, enzyme-assisted supercritical fluid, microwave-assisted, and combinations are progressively supplanting traditional methods. These methods increase extraction efficiency, improve the quality of phenolics extracted, minimize solvent loss, and reduce extraction time, enhancing the final product. These innovative approaches enhance extraction efficiency and decrease energy consumption. However, these methods face limitations, high capital investment, further optimization, and potential scalability issues. Further research and development are required to overcome these obstacles and fully realize their potential. This review highlights the benefits of combining green approaches and solvents to extract bioactive compounds. It also highlights the synergistic effect of various methods, which enhances the different properties of extracts. Using a combined extraction strategy provides an effective solution for using pomegranate peel, waste valorization, and the development of bioactive products.

This study focuses on the utilization of tofu wastewater for cultivation of mixed microalgae culture, namely Chlorella vulgaris and Nannochloropsis oculata, in a 55-L open raceway pond. Salicylic acid (SA) was added with concentration of 0, 20, and 200 µM on day 5 to induce astaxanthin production as value-added compound from microalgae biomass. The results indicated that the mixed culture of C. vulgaris and N. oculata, supplemented with 20 µM SA, exhibited optimal growth, characterized by a specific growth rate of 0.66/day, biomass gain of 0.83 g/L, biomass productivity of 0.12 g/L day, and a chlorophyll-a level of 6.38 mg/L. Moreover, Nannochloropsis oculata dominated the microalgae population by the end of cultivation period. Values of pH during cultivation increased from 9.08 to 10.22 due to photosynthetic activity of microalgae cells. The addition of 20 µM SA also yielded the highest astaxanthin level at 0.30 mg/g (w/w), indicating rapid production of astaxanthin within 7 days of cultivation period in tofu wastewater. According to this study, the use of tofu wastewater as a culture medium with SA addition is expected to increase sustainable and cost-effective production of microalgae biomass, which is a vital resource for a variety of important chemicals such as astaxanthin.

The author examines the mechanical properties of epoxy hybrid composites reinforced with boron carbide (B₄C) particle filler, Luffa cylindrica, and sisal fiber. The fibers from Luffa cylindrica and sisal were treated with 5% of NaOH solution. Composite laminates were created using the compression molding technique in various compositions such as 10–15 wt.% of Luffa cylindrica, 10–15 wt.% of sisal fiber, and 0–10 wt.% of B₄C particles with 70 wt.% of epoxy resin. As per the ASTM standards, the specimens from each composition were prepared to observe the mechanical properties such as ultimate tensile strength (UTS), flexural test, and impact test. The sample of 11.25 wt.% Luffa cylindrica/11.25 wt.% sisal fiber/7.5 wt.% B₄C particles significantly improved the UTS of 38.56 MPa and impact strength of 6 J, whereas 10 wt.% Luffa cylindrica/10 wt.% sisal fiber/10 wt.% B₄C particles had demonstrated notable improvements in flexural strength of 58.23 MPa. As a result, it is observed that the mechanical properties of the fabricated composites were markedly improved by the increment of B₄C particles. A scanning electron microscope was used to examine the morphological behavior of the fabricated composites, comprising void formation and the interfacial bond between the binder and fibers.

Transition metal oxides supported on carbon have emerged as robust catalysts for energy recovery and environment applications, like fuel cells. In this investigation, a series of catalysts with copper tin oxide (CuO-SnO₂) anchored over nitrogen doped reduced graphene oxide (N-rGO) namely N-rGO-CuSn, rGO-CuSn, and N-CuSn were synthesised for oxygen reduction reaction (ORR) application. Physicochemical characterization revealed a 3D porous structure in the N-rGO-CuSn catalyst, with CuSn oxides deposited on N-rGO sheets. Electrochemical characterization demonstrated that N-rGO-CuSn exhibited excellent ORR activity, with lower charge transfer resistance (5.1 Ω), comparable oxygen diffusion coefficient (5.3 × 10⁻⁵ cm²/s), higher specific capacitance (29.9 F/g), and higher poison resilience than 10% Pt/C catalysed electrodes. The synthesised catalyst was further examined as an electrocatalyst in a microbial fuel cell (MFC), which confirmed the superior ORR activity by achieving a maximum power density of 9.2 ± 0.2 W/m³. The results emphasise the promising competence of N-rGO-CuSn as a highly efficient catalyst suitable for energy and environmental applications, notably in MFCs and other fuel cell technologies.

As natural fibers in composites improve performance and reduce non-renewable resource use, the present study develops a vinyl ester composite reinforced with Sesbania grandiflora stem fibers which is available in nature. For the first time, the stem fiber of Sesbania grandiflora was reinforced with vinyl ester matrix via compression molding to yield a novel composite material with the detailed characterization of mechanical, physical, thermal, chemical, and fiber-matrix bonding properties. Composites are fabricated using fiber loadings ranging from 0 to 35 wt.%. The composites with 35 wt.% fiber loading had 204.2%, 101.35%, and 287.22% higher tensile, flexural, and impact strengths than those without fiber loading. The composite with 15 wt.% fibers increased hardness the most by 4.56% compared to the bare matrix material. The chemical distribution and thermal stability were analyzed using Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). TGA was employed to assess the thermal stability of the composite. The material’s eco-friendliness was demonstrated by biodegradability testing. The examination of the fracture surfaces under tension provides insights into the bonding properties between the fiber and matrix at the interface. The studies illustrate the capacity of sustainable composites in the fields of aerospace, automobile, and building.

Over the last few years, significant interest has been noted toward the utilization of natural fibers to develop sustainable composites. The demand for minimizing the use of synthetic fibers and replacing them with natural fibers in polymer composite is continuously increasing. Date palm tree has been a renowned source of lignocellulosic fibers/fillers in the development of polymeric composites. However, date palm leaves (DPL) have not been explored in woven form; therefore, in the current research endeavor, DPL have been weaved into woven mat form to investigate the DPL potential to be used as reinforcement in composite laminates. The DPL was modified with chitosan solution to enhance their thermal stability. The composite laminates were developed using direct compression molding using film stacking method. The influence of DPL reinforcement on mechanical, thermal, flammability, and dynamic mechanical behavior of the composites has been investigated and is reported. The tensile strength was found to decrease for PP-DP composites, while tensile modulus was found to increase, while, for chitosan-treated DPL reinforced composite (PP-DP-Cs), a slight improvement of about 0.81% in tensile strength was recorded, and tensile modulus was improved by 42.20%. Chitosan-modified DPL has resulted in enhanced thermal stability and recorded the reduced burning rate for the developed composites. Results indicated that with a slight compromise in mechanical properties, the developed material could be commercialized for non-structural applications under waste management scheme.