Biomass Conversion and Biorefinery最新文献

Global energy challenges are leading to research into new non-food plant substrates for liquid biofuels. The viability of raw materials plays a crucial role in the efficient biofuels production. Typha Australis, an invasive plant species with high cellulose content, has great potential for alcohol biofuel production; however, it must first be hydrolyzed to liberate fermentable sugars. In this study, typha stems were pretreated with sodium hydroxide (NaOH) at relatively low concentration to enhance its hydrolysis under varying operating variables, central composite design (CCD) was thoroughly examined, i.e. reaction time, temperature and NaOH concentration to predict the lignin removal. And the acid hydrolysis was optimized with a full factorial design. The crystallinity, surface microstructural change and functional group change of both optimally pretreated and untreated typha stem samples were studied. The suitable operating conditions optimized for NaOH pretreatment and acid hydrolysis were as follows: for the pretreatment condition: temperature 119 °C; 2.95% NaOH concentration and 58 min removed high amount of lignin and for the acid hydrolysis: temperature 130 °C concentration acid 3% for 15 min produced high amount of reducing sugar. The predict R² (0.97) was in good agreement with adjusted R² (0.95) for NaOH pretreatment the same also with acid hydrolysis with R²pre = 0.922 and R²adj = 0.863. X-ray diffraction (XRD) determination and scanning electron microscope (SEM) observation showed that the crystallinity index decreased and typha stems surface suffered from serious erosion after the pretreatment. The mild NaOH pretreatment of typha stems significantly enhanced its potential as a promising biomass to produce biofuels.

This study explores the extraction of chitosan (CH) from Sepia brevimana cuttlebone. The CH is then exposed to gamma irradiation to convert it into low molecular weight chitosan (GIR-LMW-CH). The degree of deacetylation (DDA), which is 94.2%, is conclusively confirmed by nuclear magnetic resonance spectroscopy (NMR). By using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS), the molecular weight (MW) of the isolated CH is determined to be 697.4 Da. Then, zinc oxide (ZnO) nanocomposites are created using the GIR-LMW-CH. X-ray diffraction (XRD) revealed that the ZnO generated using the sol–gel technique had a particle size of about 13 nm. The synthesized ZnO-CH nanocomposites were characterized by thermogravimetric analysis (TGA), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDX), and dynamic light scattering (DLS) analysis, which revealed a hydrodynamic size of 16 nm. This nanocomposite’s photocatalytic activity is assessed using both anionic methyl orange (MO) and cationic methylene blue (MB) dyes. ZnO-GIR-LMW-CH, which was synthesized, has an exceptional decomposition efficiency, accomplishing 98.93% degradation of MB in just 1.5 h and an astounding 99.27% degradation of MO in 4.5 h. The effect of photocatalyst amount and its recyclability efficiency was also evaluated.

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The overarching goal of current MFC research is to optimize the production of power output by exploring innovative strategies to enhance electron generation and transportation. The oxidation of the organic substrate produces glucose, which fuels the bacteria in the cell’s operational start-up and activates their electrogenic features. Consequently, organic pollutants wastewater in the MFC system may effectively increase the microorganisms’ ability to produce electrons. As a result, this research compares the impacts of naphthalene (NAPTH) and formaldehyde (FOMA) as organic pollutants in two separate MFCs that operate continuously for 70 days. The maximum power density (PD) of the system was calculated through the collected voltage. The NAPTH system produces greater power (8.73 mW/m²) over the FOMA system, having a maximum power density of 7.84 mW/m². The cell’s performance was assessed using electrochemical tests, such as cyclic voltammetry and the EIS analysis. The specific capacitance (Cp) values were found to be 0.00013 F/g and 0.00019 F/g for the FOMA and NAPTH systems, respectively. Microbial examination of the used anode electrodes was conducted. The dominant specie found were Leucobacter sp. and Pseudomonas sp. NAPTH degradation efficiency was 70% and FOMA degradation efficiency was 75% after 70 days of operation. This is the first study to investigate the impact of diverse organic pollutant degradation on MFC performance while using vegetable waste as an organic substrate. This study provides a comparative assessment of the findings, and future research directions are recommended.

In order to solve sustainability issues with its processes and products, the composites sector is concentrating on bio-waste as a different origin of materials for manufacture. The properties of Phoenix sylvestris leaf sheath fiber (PSLSF), a unique agro-waste that is separated from the tree’s leaf sheath, was discussed in this paper. The Phoenix sylvestris leaf sheaths were collected from the Phoenix sylvestris tree locations and soaked in water to loosen the fiber. After 3 days of soaking the Phoenix sylvestris leaf sheaths were washed in running water to segregate the PSLSFs. The comprehensive analysis yielded quantitative information on PSLSF, including its tensile strength (192–239 MPa), Young’s modulus (1.6–4.3 GPa), improved crystallinity index (53.6%), and cellulose proportion (64.43 wt%). Differential scanning calorimetry (DSC) and thermogravimetric (TGA/DTG) investigations shed light on the thermal stability of PSLSF and showed it durability up to 242 °C. Fourier transform infrared spectroscopy (FTIR) evaluation is used to verify the results of chemical assessment. An examination on the exterior texture of PSLSF employing scanning electron microscope (SEM) provided evidence to support the concept of utilizing it as a reinforcing component in composite with substrate as polymers. Research findings indicate that structural applications can benefit from the usage of PSLSF augmented polymeric composite.

The work deals with the extraction and characterization of fibre from the unexplored Caryota urens fruit stem (CUFS). The spadix of Caryota urens (CU) has compound spadix inflorescence with a core and branching fruit stems covered by a boat-shaped spathe. The ripened fruit stems of the spadix after the removal of peripheral fruits and their residues are used for fibre extraction process. The fibre from the fruit stem is extracted by soaking it in portable water and then pounded. The mechanical and physical properties of the unexplored CUFS are quantified by tensile test, XRD analysis, SEM, FTIR spectroscopy, and TGA analysis to ascertain their ability to be a reinforcement for bio-composites. The maximum tensile strength and strain of 10 mm fibre are 11 N and 9.9%. The XRD analysis records a 63.39% crystallinity index and a 5.078 nm crystal size. The TGA recorded the thermal stability of fibre at 250 °C with a mass reduction rate of 5.35% per min. The SEM and FTIR report the favourable features of fibre towards adhesion and interfacial bonding with the matrix. Such quantified fibres are woven as unidirectional mats and treated by silane to four variants of epoxy laminates with and without Sisal hybridization. The laminate configurations F1 and F3 are 4 layers of CUFS mat without and with silane treatment, whereas F2 and F4 represent hybridization with Sisal (Sisal/CUFS/CUFS/Sisal) and silane treated, respectively. The silane treatment has significantly improved the storage modulus of the CUFS fibre composite up to 36.96% and the CUFS–Sisal hybrid composite to 128%. The tensile strength of the silane-treated laminate (F3) has increased by 12% over the untreated (F1) laminate attributed to the effect of fibre sizing. However, the combined effect of silane treatment and hybridization has witnessed a 67.7% rise in tensile strength (F4). These characteristics of CU fruit stem fibre ensure the profound calibre to be a potential reinforcement in bio-composite for lightweight structural applications.

The widespread application of composite materials in diverse fields warrants the need of biocompatible materials to favor environmental sustainability and eco-friendliness. In this context, the rhizome of the lotus aquatic plant has attracted the exploration of its qualities for composite application. The Nelumbo nucifera (NN) is the botanical name of the lotus plant whose unused rhizome has been extracted, dried, crushed, and analyzed. The NN rhizome powder is characterized by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), dynamic light scattering (DLS), and thermogravimetric analysis (TGA). The rhizome powder has hydroxyl, carboxyl, and ether functional groups with heterogeneous surface morphology, uneven dimensions particle sizes, and coarse structure. The XRD and TGA test reported the crystalline nature of the rhizome powder with CI 57.7%, crystallite size of 2.2 nm, and thermal stability up to 290 °C. These characteristics and results extend the NN rhizome as a natural filler in polymer composites with enhanced biological sustenance.

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Lipid-extracted microalgae residue (LEMR), a by-product of the biodiesel production process, is a potential source of value-added compounds in the microalgae biorefinery field. In this research, we examined the effects of hot compressed water (HCW) conditions and microalgae to water ratios on saccharide recovery from a low-lipid strain of Chlorella vulgaris. The highest recovery yield of saccharides was 57.5% at 200℃ for 15 min. Above 200℃, the reduction in saccharide yield was observed due to the generation of gas and solid by-products. At 200℃, adjusting the microalgae to water ratio significantly influenced the saccharide yield. Reducing the microalgae to water ratio from 1:5 to 0.1:5 nearly doubled the yield. Kinetic analysis was conducted to investigate the solubilization and degradation behaviors of saccharides. The reaction orders for saccharides solubilization and degradation were identified as 1.31 and 1.79, respectively. The rate constants at varying temperatures exhibited a good fit with the identified reaction orders. The activation energies for the solubilization and degradation processes were 79.0 kJ/mol and 104.7 kJ/mol, respectively. This investigation provides insights into saccharide dynamics in LEMR under HCW conditions, offering critical information for enhancing the efficiency and sustainability of microalgae biorefineries.

In recent years, the valorization approach for transforming waste into wealth has attracted researchers to develop value-added products. This work is designed to valorize Phaseolus lunatus pod (PLP), vegetable waste, to extract pectin and bioethanol production through microbial fermentation. With the conventional method, the extraction of pectin from Phaseolus lunatus pod (PLP) was optimized using statistical and artificial neural network techniques. The Box–Behnken design of experiments and artificial neural network design were employed to optimize the extraction process and effect of process variables, namely, temperature (50–100 °C), liquid-to-solid ratio (LSR 10–40 mL/g), extraction time (30–120 min), and concentration of citric acid (30–60% w/v). The maximum yield of crude pectin (0.47 g/g) resulted from optimized process variables such as temperature 75 °C, LSR 40 mL/g, time 30 min, and citric acid 45 (% w/v). The physicochemical composition, such as carbohydrate content, protein, total phenolic content, esterification degree, methoxyl content, and techno-functional properties, was determined. The structural property, functional group analysis, thermal stability, and surface morphology of extracted pectin from PLP under optimum conditions were investigated using ¹H-NMR spectroscopy, FTIR spectroscopy, TGA, and SEM analysis. The hydrolysis obtained from residual biomass was subjected to bioethanol production through microbial fermentation with a yield of 0.11 g/g. Based on the findings, the Phaseolus lunatus pod (PLP) could be explored as a promising, cost-effective alternative for developing value-added products in food and biofuel applications.

In this study, anatase titanium dioxide (TiO₂) and 7 mol% zinc-doped TiO₂ nanoparticles (Zn-TiO₂ NPs) were synthesized using a low-cost green method based on Salvadora persica leaf extract. The NPs were characterized using Fourier transform infrared spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface area, photoluminescence, energy dispersive X-ray spectrometry (EDS), ultraviolet–visible spectroscopy, and thermogravimetric analysis. The XRD patterns indicated a pure anatase structure with crystallite size of 18.80 and 8.85 nm, TEM suggested a wide distribution of particle sizes with spherical and faceted shapes, EDS confirmed the target elemental composition of the catalyst, and BET revealed type IV isotherms with meso- and macro-pores structures, and specific surface area of 23.540 and 34.449 m²/g, respectively. The incorporation of Zn into the TiO₂ structure has reduced crystal growth, thereby decreasing both the bandgap of TiO₂ (from 3.20 to 3.14 eV) and the electron–hole recombination rate. The photocatalytic activity was tested under sunlight against nitrogenous crystal violet and methylene blue dyes. Importantly, both TiO₂ and Zn-TiO₂ have a high potential for dye degradation. The experimental data demonstrated performance enhancement of the photocatalyst after doping. In all cases, degradation data was better fit the pseudo-first-order kinetic model with a higher reaction rate observed for the doped catalyst and against methylene blue. More interestingly, even after four cycles, the catalyst’s stability and activity remained unchanged, supporting their applicability as efficient photocatalysts against organic pollutants.

The present study aimed to investigate the influence of incorporating cellulose nanocrystals in a polyvinyl alcohol (PVA) matrix to achieve the enhanced mechanical properties. Cellulose nanocrystals (CNC) were extracted from waste corncob through sulfuric acid hydrolysis. The maximized yield of CNC (41.8%) was observed at the parameters, 65 mass %, 45 ℃, and 60 min for sulfuric acid concentration, reaction temperature, and hydrolysis time, respectively. FTIR showed that CNC had evidence with various functional groups. SEM morphology showed that the prepared CNC had needle-shaped and an average length of 170.3 nm. The crystallinity index characterized by XRD for CNCs (79.3%) was found to be higher than the extracted cellulose (76.4%). In addition, the thermal stability using TGA analysis showed that the degradation temperature of the CNC reached around 327 ℃, which was higher than that of the raw corncob and extracted corncob cellulose. Further, an investigation was performed on PVA/CNC nanocomposite films that were prepared by solution casting technique using different loadings of resultant CNC (2, 4, and 6 mass%) as nanofillers. By doing so, the tensile strength, elongation, and elastic modulus of polyvinyl alcohol films incorporated with CNC nanofillers were found to be improved significantly.