Biomass Conversion and Biorefinery最新文献

This study explores the valorization of waste potatoes for bioethanol production through optimized saccharification and fermentation processes. A bifactorial experiment (P < 0.05) using Response Surface Methodology (RSM) assessed the influence of steam pretreatment, enzyme concentration, substrate levels, inoculum density, and microbial strains on ethanol yield, yeast growth, and glucose conversion efficiency. Fermentation time emerged as the most significant factor (P < 0.01), followed by substrate concentration. Under optimal conditions, the maximum ethanol yield (9.1% w/v) and glucose conversion efficiency (91%) were achieved. Saccharification efficiency (96%) was primarily influenced by temperature (65 °C), enzyme cocktail composition (α-amylase 265 U, amyloglucosidase 115 U, pullulanase 167 U), reaction time (11.5 h), and pH (6.4). The optimal fermentation conditions included an inoculum concentration of Saccharomyces cerevisiae MTCC 178 at 4.24%, a fermentation duration of 85 h, and a fermentable sugar concentration of 23%. The experimental results closely matched predicted values, confirming model robustness. This research highlights the potential of waste potatoes as a sustainable feedstock for bioethanol production, offering economic and environmental benefits. Future studies should focus on enzyme kinetics and process scale-up to enhance industrial bioethanol yields. 

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This study focused on enhancing the extraction of total phenolic content (TPC), ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity from freeze-dried Aegle marmelos seeds (FDAMS) and microwave-dried Aegle marmelos seeds (MDAMS). The optimization process employed ultrasound-assisted extraction techniques, utilizing a response surface methodology (RSM) structured with a Box-Behnken design. The factors selected for this optimization process included temperature (40–60 °C), time (30–60 min), and ethanol concentration (40–80%) for both FDAMS and MDAMS. A quadratic model was established through fifteen experimental runs, and analysis of variance (ANOVA) was performed to predict the responses and validate the model’s accuracy. The proximate analysis of FDAMS and MDAMS was conducted, revealing variations in constituent components depending on the drying technique. For FDAMS, the optimal conditions of 59 °C, 60 min, and 51.15% ethanol concentration yielded experimental values of 99.36 ± 5.05 mg GAE/100 g for TPC, 3097.02 ± 52.67 mg AAE/100 g for FRAP, and 59.12 ± 3.67% for DPPH. Furthermore, the optimal parameters for the extraction process of MDAMS were 56.9 °C, 60 min, and 79% ethanol concentration. Under these optimized conditions, the empirical results were documented as 100.36 ± 4.67 mg GAE/100 g for TPC, 2891.46 ± 61.78 mg AAE/100 g for FRAP, and 51.36 ± 2.77% for DPPH. All values aligned with the predicted results, as the residual standard error was less than 0.5%.

Lignocellulosic biomass has an enormous potential to produce liquid biofuels and platform chemicals. The present investigation evaluated the effect of pretreatment time (5–15 min) and temperature (150–190 °C) on the cellulose and xylan hydrolysis of rice straw (RS) using 0.2 M ferric chloride (FeCl₃) solution. A 2-factor (temperature and time) with a central composite statistical design in response surface methodology (RSM) was used to optimize the degradation of xylan and cellulose, and the yield of glucose, xylose, and furfural. Combining the effects of time and temperature of pretreatment and the pH of the FeCl₃ solution, the combined severity (CS) for hydrolysis of components (such as hemicellulose, cellulose) has also been evaluated. The optimum yields of glucose, xylose and furfural were obtained as 70.82, 43.34 and 70.21 g/kg of RS, respectively, whereas the optimum degradation of xylan and cellulose were 97.34% and 43.81%, respectively. The pretreated RS has been characterized by using thermo-gravimetric analysis (TGA), Fourier Transform Infra-red (FTIR), X-ray diffractive (XRD), Field emission scanning electron microscopy (FESEM) and Energy-dispersive X-ray spectroscopy (EDS) analysis. The optimum yield of glucose, obtained through the pretreatment, followed by enzymatic hydrolysis (using cellulase enzyme) was 80.34%, and the yield of ethanol obtained through fermentation of glucose (using Saccharomyces cerevisiae), was 82.4%. A mathematical model for the FeCl₃ pretreatment of Indian RS has been developed and validated for the first time. It is expected that the results of our study will open a new arena in their application in the bioenergy sector of India and abroad.

In this study, an in-situ approach was used to synthesize two activated carbons derived from the chemical activation of garcinia cola shells with KOH (AC-CBK_2/1) and ZnCl₂ (AC-CBZ_2/1) at a 2:1 impregnation ratio and a temperature of 400 °C. The physicochemical properties of AC-CBK_2/1 and AC-CBZ_2/1 were evaluated using FTIR, XRD, Raman spectroscopy, UV/Vis/NIR, SEM/EDX, and N₂ sorption techniques. Additionally, the ability of the compounds to remove indigo carmine was assessed through batch sorption and response surface methodology. The influence of three factors (pH, initial concentration and adsorbent mass) on the indigo carmine adsorption process was investigated and analyzed using the central composite design (CCD) approach. For the experiments conducted, the removal of indigo carmine by both adsorbents was favorable under the following optimum conditions: pH 2, adsorbent mass of 100.0 mg, initial concentration of 50.0 mg·L^-1, and a contact time of 80 min, with a maximum adsorption capacity of 82.004 mg·g^-1 for AC-CBK_2/1 and 79.696 mg·g^-1 for AC-CBZ_2/1, respectively, obtained using the Baudu isotherm model. Analysis of variance (ANOVA), F-ratio, and P-value showed that the models were highly accurate, with an R² value greater than 95%. The Redlich-Peterson, Radke-Prausnitz, and Hill isotherms best described the adsorption of indigo carmine on both adsorbents, revealing a heterogeneous surface and a multilayer adsorption process. This result was confirmed by isotherms with four and five parameters. The competitive adsorption between indigo carmine and thymol blue in the binary adsorption system shows a Q_Binary/Q_Single ratio less than 1, suggesting the antagonistic effect on the adsorption of indigo carmine by thymol blue. This work also shows that the synthesized adsorbents are promising for the removal of indigo carmine.

Low-cost and easily recoverable adsorbents are urgently needed for efficient treatment of dye-contaminated wastewater. In this study, a green magnetic duckweed-derived adsorbent (MDW) was synthesized via co-precipitation of Fe₃O₄ nanoparticles (NPs) onto dried duckweed using ascorbic acid (AA) as a reducing agent. The MDW exhibited a maximum methylene blue (MB) adsorption capacity of 78.59 mg/g under optimal conditions of pH 10, 50 mg/L initial MB concentration, 10 mg adsorbent dosage, and 60 min contact time, achieving a removal efficiency of 85.27%. Kinetic analysis showed that adsorption followed the pseudo-second-order (PSO) model (R² > 0.999), while equilibrium data were best described by the Temkin isotherm model, indicating heterogeneous surface interactions. Thermodynamic analysis revealed an exothermic and spontaneous process with negative ΔG° values across the temperature range of 298–318 K. The MDW retained over 69% of its initial removal efficiency after five regeneration cycles, confirming good reusability. Cost analysis estimated the synthesis cost at approximately RM 29.51/kg, highlighting economic feasibility. These findings demonstrate that MDW is a sustainable, low-cost, and magnetically recoverable adsorbent with strong potential for scalable wastewater treatment applications.

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Gasification characteristics of pear branches in different atmospheres were studied in a fixed bed gasifier. The gasification characteristics investigated included the product distribution, char properties and tar composition, which were greatly affected by the reaction atmosphere. The addition of O₂ promoted the formation of CO and CO₂, but reduced the formation of H₂, and the obtained char had a larger specific surface area and more micropores. The inclusion of O₂ and steam increased the yield of H₂ and CO₂, but decreased the yield of CO, which also increased the pore size of the char, reduced the specific surface area and enhanced the char gasification reactivity. The FT-IR analysis results revealed that the addition of O₂ and steam obviously inhibited the formation of aromatics and ethers, and made tar more reactive. The conclusions of this study have important reference value for large scale utilization of biomass resources.

In this study, Cu-doped carbon aerogel was synthesized from the cellulose of Nypa fruticans shells (Cu-SA-NCA) using sodium alginate as a cross-linked through two-step simple processes, including freeze-drying and pyrolysis. The characterization of the material was analyzed by various modern analytical techniques such as scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray powder diffraction, Fourier-transform infrared spectroscopy, N₂ gas adsorption/desorption, Raman, and X-ray photoelectron spectroscopy. The results demonstrated that the as-prepared carbon aerogel possessed a hierarchical porous structure and good specific surface. Besides, the Cu-SA-NCA exhibited a great adsorption performance toward 4-aminophenol with the highest adsorption capacity reaching 39.57 mg/g. Furthermore, the electrochemical properties of the Cu-SA-NCA were determined through a cyclic voltmeter and electrochemical impedance spectroscopy, indicating a good specific capacitance of 243.2 F/g at 5 mV/s. Moreover, the Cu-SA-NCA indicated the electrochemical sensing property toward vitamin C with the limit of detection of 0.83 µM, along with the potential in the sensing ability of this vitamin on three kinds of citrus fruits in Vietnam, including kumquat, lime, and sweet orange. According to the aforementioned results, the Cu-SA-NCA from Nypa fruticans shells is potentially applicable in environmental remediation, supercapacitor for energy storage, and electrochemical sensing.

The agricultural residue of corn cob was used as an inexpensive and abundant material for the manufacture of a green heterogeneous solid catalyst intended for the production of biodiesel from sunflower oil. The catalyst was synthesized through a straightforward calcination process at 500 °C for 3 h under ambient atmosphere. The resulting material was directly applied in the direct transesterification without further modification. The structural and physicochemical characteristics of the heterogeneous catalyst were investigated using XRD, SEM, EDS, BET, and FTIR analysis, while the alkalinity was evaluated by titration. The results revealed that the green heterogeneous catalyst consists of several active potassium phases, including KCl, K₂SO₄, K₆P₆O₁₈, K₂CO₃, and K₃AlO₃, which boost the basicity required to promote biodiesel synthesis. The catalyst reached its highest biodiesel yield (96.76%) under optimized transesterification conditions, namely 3 wt% catalyst dosage, a reaction temperature of 65 °C, a methanol-to-oil ratio of 9:1, and a transesterification time of 120 min. The catalyst was successfully reused for seven consecutive cycles while maintaining a biodiesel yield of approximately 78%. Biodiesel quality is closely compared to ASTM D6751 and EN 14,214 standards. Overall, work highlights the development of stable heterogeneous catalysts derived from inexpensive, environmentally friendly, and widely available materials, such as agricultural residue from corn cobs.

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This study investigates the integration of torrefaction and briquetting to produce a high-quality solid biofuel from eucalyptus sawdust, a lignocellulosic residue abundantly available in Brazil. Eucalyptus sawdust samples were torrefied at temperatures of 200, 225, 250, 275, and 300 °C for 30 min under nitrogen atmosphere, then mechanically densified into briquettes (18 MPa and 120 °C). The integration of these technologies resulted in torrefied eucalyptus sawdust briquettes with significantly enhanced energy density, compressive resistance, and hydrophobicity compared to raw material briquettes. Torrefaction increased the carbon content (from 46.3% to 55.6%) and HHV value (from 19.06 MJ kg⁻¹ to 24.32 MJ kg⁻¹), while reducing the O/C and H/C atomic ratios. Both mass and energy yields remained above 80% and 90%, respectively, up to 275 °C, while the highest enhancement factor (1.28) was achieved at 300 °C. However, torrefaction at 250 °C provided the best balance between fuel quality and mechanical performance of briquettes, with an energy density of 25.35 GJ.m^− 3, compressive strength of 4.68 MPa, and the highest contact angle (116.2°), indicating superior hydrophobicity. These findings confirm that integrating torrefaction and briquetting under inert conditions is an effective pathway for converting eucalyptus sawdust into high-quality solid biofuels.

The continuous microwave steam activation (CMSA) system improves biochar production and activation by eliminating the need for traditional cyclic heating and cooling processes, thereby significantly enhancing operational efficiency. This system employs microwave heating to elevate temperatures, achieving a rapid heating rate of up to 50 °C/min while maintaining optimal activation temperatures ranging from 550 °C to 600 °C. It incorporates an adjustable steam tube, which facilitates precise steam injection at peak temperatures, thereby augmenting the effectiveness of the activation process. Capable of operating continuously at a throughput of 150 g/min, the CMSA system achieves an activated char yield of 86 wt%, with the final product having a surface area of 454.90 m²/g. This approach not only accelerates the heating process but also reduces operational costs and improves energy efficiency, representing a significant advancement in the production of activated biochar.