Biomass Conversion and Biorefinery最新文献

Hydrothermal carbonization (HTC) was adopted as a promising approach for improving fuel quality for several high-moist biomass. In this study, the Rhizoclonium riparium macroalgae (RMA), an abundant marine alga in an aquaculture pond, was successfully converted into hydrochars as a sustainable solid biofuel. The Box Behnken design (BBD) was applied for the HTC experiment to investigate the individual and interactive effects of operating parameters, including HTC temperature, reaction time, and water ratio, on hydrochar physicochemical characteristics and fuel properties. The response surface optimization (RSM) revealed maximum mass yield (MY) of 79.1%, higher heating value (HHV) of 23.6 MJ/kg, and energy yield (EY) of 94.4%. The RSM-BBD of process parameters and their HTC effects showed that the decreasing MY and EY were significantly due to the HTC temperature and residence time. From ANOVA analysis, temperature, time, and water ratio were the most significant parameters responding to MY, HHV, and EY. The optimal conditions for hydrothermal carbonization (HTC) of RMA as a solid biofuel were determined to be a temperature of 200 °C, a duration of 2 h, and a water-to-biomass ratio of 1:1, producing the highest energy yield (EY) of 95.3%. Utilizing RSM-BBD to investigate HTC parameters for hydrochar production is a suitable effort for technical scalability.

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In this study, a single-chamber microbial fuel cells (MFCs) was employed to address the challenges of low electron generation and organic pollutant treatment. It specifically targeting cresol as the organic pollutant and commercial sugar as the organic substrate. The system operated with an external resistance of 1000 ῼ, achieving a maximum voltage of 300 mV within 35 days of a 45-day operation period. The open circuit voltage reached 400 mV, and the peak power density was 6.03 mW/m² at 1000 ῼ, while other resistances ranges failed to provide stable electron generation. The maximum current density recorded was 42.10 mA/m², with an internal resistance of 739.19 ῼ. Biofilm analysis revealed solidification and maturation, with the cresol system peaking at a capacitance value of 0.00009 F/g on day 35. Electrochemical tests also indicated stable electron transfer on day 35. Cresol degradation efficiency improved from 0% to 93.04% over the study period. Biological analysis highlighted biofilm formation on the anode, crucial for oxidizing substrates and electron transfer. Phylogenetic analysis identified key bacterial strains, including Bacillus and related genera, contributing to the MFC’s performance. The study also discusses commercial sugar oxidation, electron transport, and recommendations for MFCs development.

Second-generation bioethanol derived from rice straw faces several challenges, including complex processing stages that involve pretreatment, hydrolysis, and fermentation. Physical, chemical, and physicochemical pretreatments require significant energy, generate chemical waste, and are not environmentally friendly. Current methods for second-generation bioethanol production, such as separate hydrolysis and fermentation (SHF), simultaneous saccharification and fermentation (SSF), and simultaneous saccharification and co-fermentation (SSCF), remain inefficient due to the separation of enzyme production from hydrolysis and fermentation. This study aims to enhance the efficiency of the production process by integrating fungal pretreatment using Pleurotus ostreatus and consolidated bioprocessing (CBP) using a consortium of Trichoderma reesei and Saccharomyces cerevisiae via a one-pot system. Response surface methodology (RSM) using central composite design (CCD) was employed to optimize bioethanol production. The lignin, cellulose, and hemicellulose contents of rice straw decreased by 31.80%, 6.75%, and 11.65%, respectively, after pretreatment for 21 days. The solids concentration of 34.7% produced the highest bioethanol yield of 27.51 mg/g whole pretreated rice straw (WPRS) at 38 °C for 192 h. Integrating fungal pretreatment and CBP using a microbial consortium resulted in a bioethanol yield of 92.17 mg/g rice straw for 29 days. This study introduces a novel method for producing second-generation bioethanol from rice straw that is both more efficient and environmentally friendly. These findings provide a foundation for further research on the industrial-scale development of second-generation bioethanol from rice straw.

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Response surface methodology (RSM) is crucial in optimizing complex processes like reducing sugar production, offering a systematic approach to parameters, and analyzing the intricate interactions between multiple factors to maximize sugar yield. The current study focuses on enhancing sugar production from corn stover biomass using the nanotechnology-based pretreatment. Corn stover was pretreated with photocatalytic aluminum-doped zinc oxide (Al-ZnO) nanoparticles under ultraviolet irradiation. This was followed by dilute acid (H₂SO₄) and basic (NaOH) hydrolysis to measure the formation of sugars (glucose, arabinose, galactose, mannose, and xylose). A Box-Behnken design within RSM was used to optimize operating parameters such as ultraviolet irradiation time, Al-ZnO nanoparticles concentration, and H₂SO₄ and NaOH concentrations. The results showed that longer UV irradiation exposure had an inverse effect on sugar production, while nanoparticle concentration had a direct and positive effect on sugar production. In photocatalytic acid hydrolysis, the sugars yield reached up to 19.02 g/L at 75 UV time, 1 g/L Al-ZnO nanoparticles, and H₂SO₄ concentration of 2mmnM. For basic hydrolysis, a higher sugar yield of 15.76 (g/L) was achieved at 75 UV time, 1 g/L Al-ZnO nanoparticles, and NaOH concentration of 1.25 M.

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In this study, an environmentally friendly avocado seed starch-based hydrogel capable of controlled-release fertilizer delivery was successfully fabricated by employing a redox system of KMnO₄/NaHSO₄ and grafting itaconic acid onto Vietnam Booth avocado seed starch. The starch was obtained from avocado seed agricultural waste by a green extraction method using water as a solvent. Starch oxidation resulted in hydrogels with high gel fraction values. Scanning electron microscopy (SEM) analysis revealed significant morphological changes: the granular structure of the starch was disrupted, and the hydrogel’s surface became roughened. X-ray diffraction (XRD) results indicated that the fabricated hydrogel exhibited a V-type crystalline structure, and a reduction in crystallinity was observed as the concentration of itaconic acid rose. Fourier-transform infrared spectroscopy (FTIR) analysis showed alterations in the chemical structure of the starch after oxidation and itaconic acid grafting. The hydrogels indicated relatively low water absorption capacity in various media (distilled water, NaCl solution, and CaCl₂ solution) compared to that of current commercial hydrogels. The compressive strength results indicated that an increase in itaconic acid concentration tended to enhance the compressive strength of the fabricated hydrogel materials. The hydrogel samples exhibited an absorption capacity of approximately 60–70% for both KNO₃ and (NH₄)₂SO₄ fertilizers. Furthermore, fertilizer release studies in distilled water showed that KNO₃ was almost completely released after 100 h, while approximately 85% of (NH₄)₂SO₄ was released over the same period. The biodegradation characterization results showed that the remaining weight of the fabricated hydrogel material was approximately 33% after 21 days of soil burial. These findings highlight the Vietnam Booth avocado seed starch as a potential sustainable and eco-friendly raw material for fabricating environmentally friendly hydrogels with controlled-release fertilizer capabilities, applicable in smart agriculture field.

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We compared oil recovery from Moringa oleifera seeds using two techniques: Soxhlet extraction (SE) and Ultrasound-Assisted Extraction (UAE) with petroleum ether (PE) and hexane as solvents. Soxhlet extraction with petroleum ether yielded the highest oil recovery (46.92%), surpassing UAE with petroleum ether (20.04%). Similarly, Soxhlet with hexane (40.08%) produced a higher yield than UAE with hexane (28.32%), highlighting the significant impact of extraction methodology on oil recovery. UAE offered a more efficient alternative, requiring three times less solvent and five times shorter processing time while yielding oils with lower acidity, better stability, and superior quality. Fatty acid profiling identified oleic acid (70.0%) as the predominant component, followed by palmitic acid (20.0%), making these the major constituents of Moringa seed oil. UAE-extracted oils exhibited higher unsaturated fatty acid (UFA) levels, a higher iodine value, and lower oxidative stability indices (COX values), reinforcing their superior quality. Additionally, Moringa seed cake demonstrated significant efficacy in water treatment, reducing microbial load by 59.42% and turbidity by 79.64%. These findings highlight Soxhlet extraction as the preferred method for maximizing oil yield. In contrast, the UAE emerges as a sustainable alternative for high-quality oil production with lower solvent consumption and reduced processing time. Moreover, the water-treatment performance underscores the broader eco-friendly potential of Moringa oleifera by-products.

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In this study, watermelon powder was produced with MD and MACD drying systems and maltodextrin, corn starch carrier agents at rates of 5, 10%. The effects of drying systems and carrier agents on MR, DR, D_eff, SMER, SEC, and greenhouse gas emissions values of watermelon powders were compared. Drying systems and carrier materials affected the drying kinetics, energy and greenhouse gas emission values of watermelon powders. It has been determined that the average DR values of watermelon powders vary between 0.0806 and 0.1053 g moisture/g dry matter.minute. The D_eff values of watermelon powder ranged between 8.25 × 10^− 7 − 1.49 × 10^− 6 m²/s. The mean SMER and SEC values of the drying processes ranged 6.50–9.51 × 10^− 3 kg/kWh and 105.12–153.86 kWh/kg, respectively. The values of greenhouse NO_x, SO₂, and CO₂ in the watermelon powder production processes ranged 1.47–6.18, 0.0–16.30, and 345.60–1118.21 g, respectively. Drying systems and carrier agents affected the color values of watermelon powders. Watermelon powders with the lowest L value were determined in the method using 10% maltodextrin carrier agent (p < 0.05). The predominant red a color value in watermelon fruit varied between 15.94 and 23.43. Drying processes and carrier agents affected the color value b. The b color value of the produced watermelon powder varied between 11.50 and 24.59. Micorwave drying systems are suitable for use in the production of watermelon, especially in terms of kinetics, energy consumption and greenhouse gas emissions properties.

This study proposed an innovative biomass gasification hydrogen production pathway based on secondary reforming, aiming to address the low hydrogen yield caused by incomplete gasification in traditional processes. Eight typical biomass feedstocks were used as raw materials, and the complete process flow-comprising pretreatment, pyrolysis, gasification reforming, secondary reforming, syngas pressurization and low-temperature methanol washing-was simulated. The results were analyzed, and parameters optimized. Key parameters were determined through orthogonal experiments: gasification temperature (895 °C), gasification pressure (1 bar), and SBR (0.3 kg·kg⁻¹). Under these conditions, the syngas components had the following molar fractions: 51.10% H₂, 34.17% CO, 1.09% CO₂, and 0.01% CH₄. The lower heating value of the syngas was 254.2 kJ·mol⁻¹, and the system’s exergy efficiency reached 70%. Compared to the traditional gasification process, secondary reforming nearly completely converted CH₄, significantly improved H₂ selectivity, and increased system exergy efficiency by over 15%. Additionally, cow dung showed the highest H₂ yield and energy efficiency among all feedstocks. This study provided a new theoretical perspective on optimizing biomass gasification for hydrogen production, clarified how secondary reforming enhances H₂ selectivity and system efficiency, and offered theoretical support for future technical optimization.

This study explores the synthesis and optimization of biofuel briquettes derived from a blend of cotton stalk, Prosopis Juliflora, and sesame biomass for sustainable cement pyroprocessing. The biomass was subjected to torrefaction, with the process parameters—temperature, time, and composition—optimized using Response Surface Methodology (RSM) to enhance calorific value and reduce carbon emissions. Proximate, ultimate, FTIR, SEM-EDX, and ash chemistry analyses were conducted to characterize the briquettes. The optimized torrefaction conditions were determined to be 166.06 °C for 47.70 min with a blending composition of 40 wt%, resulting in a calorific value of 6.25 Mcal/kg. The briquettes exhibited favorable physical properties including a bulk density of 1.03 g/cm³, shatter resistance of 95%, water penetration resistance of 50.45%, and impact resistance of 60%. Ash analysis revealed significant contents of SiO₂ (47.54%), Al₂O₃ (24.65%), and CaO (9.42%) indicating their suitability for cement pyroprocessing. This research demonstrates the potential of biofuel briquettes to mitigate greenhouse gas emissions and reduce reliance on imported fossil fuels in the cement industry, promoting environmental sustainability.

In response to the global water scarcity crisis, this study explores the use of waste sawdust (WS), which is an underutilized lignocellulosic byproduct of the timber industry, as a sustainable feedstock for photothermal conversion materials (PCM) in interfacial solar vapor generation (ISVG) systems. Carbonized sawdust hydrochars (CSHs) were produced from WS via eco-friendly and efficient microwave-assisted hydrothermal carbonization (MHC) at 230 °C with residence times of 30, 60, and 90 min, yielding samples denoted as CSH30, CSH60, and CSH90, respectively. All resulting CSHs exhibited a rougher surface morphology, a BET surface area of approximately 5.7 m² g^− 1, enhanced carbon content (~ 80%), and broad-spectrum light absorption. Hydrochar-based solar absorbers (HSAs) were fabricated and tested in an outdoor ISVG setup using seawater under direct solar irradiation (1.18 kW m^− 2). Among them, HSA30 (based on CSH30) demonstrated the most optimal performance, achieving a photothermal efficiency of 66.45% and an evaporation rate of 1.15 kg m^− 2 h^− 1. Extending the residence time beyond 30 min yielded negligible improvement in performance. Heat loss analysis of HSA30 showed a low total heat loss of 13.8%. HSA30 also successfully rejected salt by dissolving and absorbing accumulated salt. The condensed vapor yielded clean water with a salinity of 220 ppm and a pH of around 6.85, meeting the World Health Organization (WHO) drinking water standards. These findings demonstrated that CSH derived via MHC is an efficient material for solar desalination.