Biomass & Bioenergy最新文献

Production of jet fuel is not only promising but challenging in the field of biomass utilization. Here we proposed a novel route to produce highly branched alkanes with ultra-low freezing point using n-butyraldehyde as feedstock by self-aldol condensation and subsequent hydrodeoxygenation (HDO). The catalyst characterization revealed that the MgO-SiO₂ catalyst played an acid-base synergetic effect role in the self-aldol condensation of n-butyraldehyde using n-butanol as solvent, which obtained C8 oxygenate and C12 oxygenate with yield of 69.3 % and 26.8 % respectively. The medium Brønsted base site of the catalyst captured α-H to promote the formation of enolate from n-butyraldehyde, and the Lewis acid sites promoted the dehydration of intermediate products. DFT simulation showed that n-butanol activated α-C in enolate in aldol condensation, and deactivated the oxygen atoms in enolate by hydrogen bonds to inhibit side reactions. Finally, the obtained condensation products were subjected to HDO reaction over the 5 wt% Pd/C and HZSM-5 catalysts, obtaining the highly branched alkanes with an ultra-low freezing point of -120.7 °C for C8 alkane and -78.7 °C for C12 alkane suitable for bio-jet fuels.

The study explored the potential of activated carbon from mixed municipal solid waste (MSW) char produced at 250 and 350 °C. The resulting char was activated using NaCl, KOH, and ZnCl₂, serving as a novel precursor to optimizing the synthesis conditions for cost-effective activated carbon aimed at removing Pb(II) from water. Characterization techniques, including proximate analysis, iodine number, pH, BET surface area, XRD, FTIR, FESEM, and atomic adsorption spectroscopy, were employed to identify the most effective activated carbon for Pb(II) removal. The findings revealed that KOH-activated carbon produced from char at 250 °C exhibited the most potential adsorbent and fell within the range of commercial activated carbon. Batch adsorption experiments using KOH-activated carbon demonstrated the highest Pb(II) removal of more than 90 % under optimized conditions of pH 6, 1 g activated carbon, zero contact time, and 1000 mg/L metal concentration. The adsorption kinetics followed Lagergren's second-order model, and the isotherm suggested the Langmuir model with an R² value of 0.99. Additionally, the cycle study revealed that the activated carbon could be reused for up to two cycles with 90 % adsorption efficiency. Desorption experiments showed that HNO₃ was the most effective eluent, achieving 80 % removal efficiency at pH 1. The recovery rate of MSW char-activated carbon (MSW-AC) after desorption was approximately 64.89 %. Thus, the performance of MSW-AC in adsorption, desorption, and cycle studies is recommended as an effective adsorbent for heavy metal mitigation. Furthermore, its utilization represents a valuable strategy for waste management, contributing to waste minimization efforts.

The surge in Waste Electrical and Electronic Equipment (WEEE) volume presents a formidable disposal challenge. This study focused on catalytic pyrolysis of waste printed circuit boards (WPCBs) employing Ca(OH)₂ alone and in conjunction with ZSM-5 as catalysts. Kinetic parameters for catalytic and non-catalytic pyrolysis were derived through thermogravimetric analysis (TGA). The Coats-Redfern method for non-catalytic pyrolysis showcased activation energies of 33.52, 405.81, and 67.96 kJ/mol in zones 1, 2, and 3, respectively with corresponding reaction orders of 0.9, 2.8, and 1.2. Introduction of Ca(OH)₂ amplified activation energy and reaction order in zones 2 and 3. Subsequent incorporation of ZSM-5 with Ca(OH)₂ resulted in reduced activation energy and reaction order in zone 2, while elevating them in zones 1 and 3. Validation through laboratory-scale fixed-bed reactor experiments confirmed TGA findings and unveiled that pyrolysis oil had enhanced phenolic yield because of ZSM-5 where Ca(OH)₂ showcased its effectiveness in eliminating halogens.

Lignocellulosic wastes have garnered interest in activated carbon (AC) production owing to their abundance and cost-effectiveness. This research utilized coffee husk as a precursor for AC. The methodology involves impregnating the waste with varying proportions of phosphoric acid (H₃PO₄), 1:1 and 1:3 (mass_waste:mass_H3PO4), and activation in a microwave oven, with different power and activation times. The N₂ adsorption/desorption results demonstrated high surface areas (S_BET) for the ACs. The optimized AC (C_1:3-1000-10) was obtained using a time of 10 min, high impregnation ratio, and power, resulting in an S_BET of 1200 m² g⁻¹. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra confirmed the presence of functional groups, such as hydroxyl and ester, on the AC surface. Adsorption tests with sulfamethazine (SMZ) showed a 225 mg g⁻¹ remotion capacity, highlighting the waste potential for sustainable and economical AC production. This underscores the importance of optimizing activation parameters to enhance performance and application versatility in AC production from lignocellulosic sources.

Commercial cultivation of the Macauba palm is growing due to its agro-energy potential. This study quantified carbon stock in two macauba plantations (4.8 and 9.0 years old), considering carbon stored in soil and biomass. We assessed total organic carbon (TOC) stocks in labile (EOC and LF-C) and non-labile (NL-C) soil fractions, comparing these with a forest regenerating for over 30 years. Soil samples were collected within the palm plantation (rows and inter-rows) and the forest area at five depths (0–10, 10–20, 20–40, 40–60, and 60–100 cm). The impact of plantation age and sampling position on TOC stocks and organic matter fractions across different soil layers (0–100 cm) was assessed. The Carbon Management Index (CMI) was calculated to evaluate carbon recovery. Plantation age and sampling position influenced soil TOC stocks across all depths up to 1 m. Higher TOC and NL-C soil stocks were observed in the older plantation (9.0 years) and inter-row. EOC and LF-C fractions varied by soil layer. The inter-row region of the 9.0-year-old plantation exhibited higher carbon recovery based on the CMI. Over 4.2 years of palm cultivation (between 4.8 and 9.0 years), carbon accumulation in biomass and soil reached 75.36 Mg C ha⁻¹. These findings underscore the potential of commercial macauba plantations to enhance soil carbon stocks rapidly, particularly in inter-row areas. Plantations younger than a decade surpassed the soil carbon stock of a forest regenerating for over 30 years, highlighting significant environmental benefits of macauba cultivation, including soil and biomass carbon sequestration.

Lignocellulosic biomass offers a sustainable and renewable method for producing high-quality fuels and value-added chemicals. In this study, residues from peach palm (top, inner sheath, and meristem), sugarcane (top), and pineapple (mother plant) were characterized based on their physicochemical properties and thermal degradation behavior to estimate their bioenergy potential. The biomass residue kinetic constraints were analyzed using three isoconversional models: the Flynn–Wall–Ozawa (FWO), Kissinger–Akahira–Sunose (KAS), and differential Friedman (DF) models. Physicochemical characterization showed the peach palm top's notably high cellulose content of 35.71 ± 0.47 % wt. Calorific values of the residues ranged from 13.73 ± 0.08 to 16.91 ± 0.90 MJ kg⁻¹. X-ray diffraction analysis indicated the carbonaceous and crystalline nature of the biomass residues. Mean activation energy values ranged from 105.02 to 370.10 kJ mol⁻¹ for KAS, 111.50–360.99 kJ mol⁻¹ for FWO, and 108.60–360.27 kJ mol⁻¹ for DF. Finally, thermodynamic analysis revealed the endothermic nature of the pyrolysis process across the entire conversion range for the samples. Overall, these samples demonstrate major potential as feedstock for biorefineries and the development of Ecuador's circular economy.

Thermophilic fungi are superlative microorganisms for enzyme production, especially cellulase, and their using in biotechnological applications is due to their stability at utmost temperatures. In the current investigation, we isolated six genera encompassing six fungal species and one species variety from 30 samples of compost at 45 °C and 55 °C. Thermomyces lanuginosus was the most rampant species. The colony diameter of T. lanuginosus ranged from 2.8 to 4.3 cm at 45 °C on yeast-starch agar (YpSs) medium with white or greyish-brown mycelia. Fifteen isolates of T. lanuginosus were cellulase producers with variable competencies with a C/Z range of 1.09–1.38 cm. Fascinatingly, the clear zone diameter was much bigger when using Iodine than those obtained using Congo red. T. lanuginosus isolate no. 33 produced substantial amounts of cellulase on the four used media: Corncob (CC), Corncob treated with NaOH (C-NA), Yeast Peptone Dextrose (YPD), and CarboxyMethyl Cellulose (CMC) with the highest activity on CC; 143.9 μg/min, also cellulase gene expression levels of cel6Aq, cel7Aq, and bgl3Aq genes exhibited higher fold changes in the CC condition (7.26-fold, 11.51-fold, and 3.39-fold, respectively). X-ray fluorescence (XRF) analysis revealed the presence of 11 minerals with higher concentrations in CC than in C-NA. Supplementation of corncob medium with rosemary essential oil (CR) completely inhibited cellulase production. It adversely affected the growth, and changes in conidia, which were depicted using a scanning electron microscope (SEM). Interestingly, the conidia appeared much bigger than other media, and the large conidia diameter was 10.2–12.1 μm.

The projected escalating use of renewables to meet the Paris Agreement goals has raised concerns about land-use pressures, particularly from biomass-based systems. This study introduces the concept of Integrated Food, Energy, and Materials Systems (IFEMS) as a strategy to optimize land-use efficiency for decarbonization. To evaluate the land-use efficiency of IFEMS and other renewable resource-based systems, a novel parameter termed decarbonization density (DD) is proposed, which aggregates all services that reduce GHG emissions and remove carbon from atmosphere per unit of land. A case study on an archetypical integral sugarcane utilization system in Brazil is analyzed, indicating that the simultaneous production of food, energy, and materials can synergistically aid decarbonization efforts. The estimated DD for the baseline scenario is 20 tCO₂e/ha, while in the innovative scenario (SC-innov), it rises to 145 tCO₂e/ha. Most of this increase stems from including the production of fermented meat as a substitute of beef, which accounts for three quarters of DD's value in SC-innov, indicating a high potential of this technology for contributing to decarbonization. These findings suggest that IFEMS may represent a land-use strategy at least as efficient as other renewable energy systems, with the potential to grow as biomass conversion technology advances into more complex systems. However, these advances also pose the challenge of integrating diverse product streams for different markets, which will likely require the coordination of multiple stakeholders within an industrial ecosystem rather than a single-actor model.

A model for the fast pyrolysis of anisotropic biomass particles is presented which considers bubbling dynamics within the liquid intermediate phase (metaplast) and aerosol ejection from this phase. The model employs the population balance equation and the method of moments to estimate the production rate and resultant size distribution of aerosol ejections, incorporating a detailed CRECK reaction mechanism, and considers the effect of anisotropic biomass microstructure on the intraparticle transport of mass and energy. This study investigates the impact of particle size, heating rate (heat transfer coefficient), and lignocellulosic composition on aerosol ejection. The model predicts that, at high heating rates (convective heat transfer coefficient of 359 W/m².K), aerosols can contribute over 20% to the heavy fraction yield in bio-oil for small particles (1 mm diameter, 4 mm length). The model can predict aerosol size distribution and surface area, indicating an average size of 20 μm for bubbles and 5 μm for aerosols during increased bubble production and aerosol ejection rates. These findings are consistent with prior experimental results and provide essential information for future modeling of extra-particle reactions of the aerosols as they progress through the reactor.

Cities worldwide face a significant public health and environmental challenge in handling municipal solid waste (MSW). This research exposed an effective utilization of MSW as the source for hydrogen production via a supercritical water gasification process under 450–650 °C at 15–45 min processing time. The impacts of gasification temperature and processing time on the functional properties of hydrogen production are studied. Its results are compared to identify the optimum processing temperature and processing time to adopt the system. Integrating 3 wt% silicon dioxide (SiO₂) nanoparticles/3 wt% of potassium carbonate (K₂CO₃) enhances hydrogen production by increasing the catalyst's surface area and improving the stability of active sites, leading to more efficient gasification reactions. Increasing the gasification temperature from 450 to 650 °C significantly raises the hydrogen molar fraction and gas yield with peak gasification efficiency (GE) and hydrogen efficiency (HE) values. The gasifier functioned with catalyst (3 wt% K₂CO₃/SiO₂) under 650 °C gasification temperature and 45min gasification time influenced better output responses like improved hydrogen gas yield of 63.7 mol/kg, higher gasification efficiency of 59.8 %, better hydrogen efficiency (63.4 %) and increased carbon conversion efficiency of 63.4 and 42.5 % respectively.