Biomass & Bioenergy最新文献

The ongoing energy crisis and global warming threat represent major challenges of the century. Our dependence on conventional fuels has reached to a critical level where attempts are made to reduce the greenhouse gases (GHGs) emission and impede its ramifications. Simultaneously, it is projected to have alternative greener energy resources to reduce the deleterious effect of biofuels on humans and the environment. The lignocellulosic biomass (LCB, an abundant feedstock) constitutes an important renewable resource with potential to replace non-renewable ones for energy production. The shift in the usage of natural resources projects biofuels on the forefront to overcome the growing energy crisis and offer a sustainable solution to the global warming to minimize its impact at the global scale. Offering a long-term viability, biofuels upholds a key component in the economic prosperity of a nation. This article highlights important aspects of feedstock selection, a concise and comprehensive account of the pre-treatment procedures, and enzymatic saccharification of the LCB employed in the biofuel production. Considering the biomass heterogeneity and optimization in predicting and managing the outputs and huge capital and operating expenditures, the study presents integration of the microbial saccharification with established biofuel technologies towards enhancing efficiency and overall productivity. Additionally, an account of the artificial technology and machine learning approaches employed in harnessing renewable resources and reducing greenhouse gas emissions, have been added. Holding a greater promise, the review adds to the need of developing robust and efficient LCB conversion methods to scale up and excel in sustainable energy production for a greener future.

The collection of Waste Cooking Oils (WCOs) has been growing in recent years due to the increase in society's awareness of environmental aspects since the uncontrolled disposal of WCOs has substantial adverse environmental impacts. WCOs are potential secondary raw materials for producing environmentally friendly biodiesel, which reduces pollution, promotes renewable energy use, and decreases waste. Nevertheless, the presence of several degradation products requires different pre-treatments before their conversion, significantly impacting the economic feasibility of the process. In addition, even pre-treated WCOs may have physical and chemical properties that do not guarantee the production of good-quality biodiesel. Therefore, it is essential to know the degradation reactions occurring during the oil frying and successive storage. Only WCOs that satisfy specific criteria would be used for high-quality biodiesel production. Then, a collection and storage method aimed at biodiesel production should be promoted. The current collection method does not provide for any special measures, storage containers, and temperatures. Instead, it is desirable to have proper collection and storage of WCOs to minimize degradation and have good WCOs before the conversion into biodiesel. Any business generating WCO should be provided with specialized, food grade, stainless steel, or plastic oil storage units that streamline the used cooking oil collection and are ready for scheduled collection. Managing household WCOs appears more complicated, but simple operations such as preliminary filtration and suitable containers can limit undesired reactions with air, light, and humidity, together with a more frequent collection of WCOs by waste disposal companies.

The preparation of high-performance porous carbons (HPPCs) using biomass as adsorbent is a viable strategy for the treatment of ibuprofen (IB) in water. In the present study, pyrolyzed carbon was prepared from duckweed (DW) and rice straw (SW) at 400, 500, and 600 °C, and subsequently mixed pyrolysis with KOH to prepare the HPPCs. The HPPCs were used for the treatment of ibuprofen (IB) in water to evaluate their absorption performance. The physicochemical properties of biochar and HPPCs were investigated using scanning electron microscopy, X-ray electron microscopy, Raman microscopy, and the Brunauer-Emmett-Taylor method. In IB adsorption experiments, adsorption equilibrium was evaluated using Langmuir and Freundlich isotherm models. The maximum adsorption capacities of DW and SW were 0.952 and 0484 g/g, respectively, at an IB concentration of 0.5 g/L. The adsorption capacity of HPPCs for IB is influenced by a multifactorial combination of the specific surface area, nitrogen content, and nitrogen-containing functional groups on the surface. Generally, the HPPCs showed great potential for the removal of the IB pharmaceutical contaminants from aqueous solutions.

The current production of aromatic hydrocarbons, crucial in fuel and polymer production, relies heavily on fossil resources. Finding carbon-neutral alternatives is necessary to address the current environmental challenges. Lignin emerges as a promising source for bio-based aromatics. However, existing catalytic hydrodeoxygenation processes often yield mixtures of cycloalkanes and aromatics. In our study, we investigated a selective route to obtain aromatics from phenols using the keto-tautomer reaction mechanism. According to this mechanism, the initial hydrogenation of the carbonyl group while a phenol compound is in its keto form leads to the removal of the hydroxyl group while preserving the aromatic structure. Our experiments focused on p-cresol, guaiacol, and mequinol, employing Pd/C and Ru/C catalysts. Experimental results revealed that aromatic hydrocarbons were favored during the hydrodeoxygenation of p-cresol and mequinol, while steric effects from the methoxy group hindered guaiacol's conversion. Furthermore, we observed significantly higher conversion rates when using hydrocarbon solvents compared to water, with toluene yields of up to 13.5 % by mass achieved on Pd/C. Our computational simulations confirmed the feasibility of the keto-tautomer mechanism on Pd cluster surfaces, similar to those found in Pd/C catalysts.

Dark fermentation of cheese whey (CW) for the production of biohydrogen generates an acidic effluent, containing high concentrations of volatile fatty acids, which needs to be further treated before disposal and possibly further valorised. This study develops a dual-chamber Microbial Electrolysis Cell (MEC) that achieves simultaneously the reduction of the organic content of this effluent to environmentally acceptable levels, along with bio-electrochemical reduction of CO₂ to CH₄. The MEC was operated for 140 days and the effect of the following conditions on the MEC performance was examined: (a) the feed concentration of the acidic fermentate (in the range 6–81 g_COD/L), (b) the conductivity of the feed modified via KCl addition (range 2–22 mS/cm), (c) the MEC operation mode (with or without catholyte renewal) and (d) the solids content (modified via CW filtration prior to its use). The results showed that high COD removal (>95 %) was achieved in all cases, along with a CH₄ production of up to 1.1 mmol/g_CODconsumed. The best performance of the cell was obtained for a feed COD concentration of ∼30 g_COD/L and a feed conductivity of ∼15 mS/cm; these conditions resulted in a COD removal exceeding 99 %, a CH₄ production of 1.1 mmol_CH4/g_CODconsumed and a net energy production of 15.8 % compared to the energy demand of the system. The electrochemical study of the system revealed that higher and lower feed COD concentrations were characterized by higher internal resistances. The results indicate that the MEC can be exploited for further treatment and valorization of a high-strength effluent along with the production of CH₄ with an energy surplus, as an efficient waste-to-energy technology.

Biomass-derived charcoal, possessing high surface area, temperature resistance, and stability, has diverse applications. Traditional methods overlook its conductivity. In this work, a new approach was devised. By controlling the pyrolysis temperature and preparation atmosphere, rice straw was converted into biochar electrodes at 1000 °C in a N₂-containing environment. The temperature effect on the conductivity of biochar made from rice straw was elucidated through methods such as resistivity measurement, XRD, and Raman spectroscopy. Furthermore, the biochar electrode material was employed as the cathode and the electro-deposition method was employed to treat wastewater containing Cd. The results indicated that the treatment efficiency of simulated Cd wastewater can reach a maximum of 88.96 % in 7 h at relatively low power consumption. After the reaction, a simple acid washing step effectively separated the electrode and Cd, which allowed the Cd to be recovered and the electrode to be used again. This method offers a innovative low-cost, high-efficiency technique for preparing biochar electrodes from rice straw, achieving sustainable waste conversion while providing new techniques and novel solutions for electro-deposition in heavy metal wastewater treatment. Therefore, the research hold significant practical a significance and scientific value.

After acidic and high-temperature pretreatment of lignocellulosic biomass, researchers find that some lignin-like substance appeared on the surface of cellulose, which is called pseudo-lignin. Pseudo-lignin can be formed through carbohydrate degradation or substitution reactions on the aromatic ring of lignin. Pseudo-lignin is identified as Klason lignin in compositional analysis, whereas in Py-GC-MS analysis, it is recognized as material derived from carbohydrates. Pseudo-lignin is an aromatic substance. Similar to lignin, it also affects enzymatic hydrolysis efficiency by blocking the enzymatic reaction sites of cellulose and non-productive adsorption with cellulases. In order to offer theoretical guidance and technical support for the advancement of cost-effective and efficient new pretreatment technology, this review summarizes the latest advancements in research concerning the origins of pseudo-lignin, its effects on enzymatic hydrolysis, and the strategies that inhibit pseudo-lignin formation.

The paper presents a techno-economic comparison among five alternative process configurations for bio-methanol production from the gasification of residual forestry biomass. Process design and simulations are performed in Aspen Plus for mass and energy balance calculation, followed by preliminary sizing and economic analysis. Process schemes include a gasification island (state-of-the-art low-pressure gasification compared against a high-pressure gasifier) with syngas conditioning and compression, heat recovery, syngas composition adjustment (by CO₂ capture or addition of hydrogen produced by electrolysis), methanol synthesis and purification and a heat recovery cycle for power generation. CO₂ capture is performed with conventional chemical absorption in the benchmark cases, while low-temperature partial condensation of CO₂ is modeled in the advanced scenario. Methanol output is 14–15 kt/y in the CO₂ capture cases and 36 kt/y in the H₂ addition option.

Configurations with a pressurized gasifier and phase-change-based CO₂ separation are the most efficient ones, with a primary energy efficiency of 50 % and a Levelized Cost of Methanol (LCOM) of 700 €/t_MeOH. In comparison, LCOM increases to 730 €/t_MeOH in the case with conventional capture or between 792 €/t_MeOH and 831 €/t_MeOH (depending on the CCS technology) if the gasification pressure is conservatively reduced to 2.5 bar. In the H₂ addition scenario, LCOM increases to 821 €/t_MeOH due to the significant impact of the electricity consumption for H₂ production, (only partly compensated by the increased methanol production). Scenarios with CO₂ capture feature negative CO₂ emissions, in the range −1.64 to −1.84 t_CO2eq/t_MeOH, as a result of the capture and storage of biogenic CO₂ (BECCS approach).

The primary objective of this study was to assess the feasibility of utilizing urine-prepared NaOH solution (NUr) as an innovative pretreatment approach for enhancing BHP in rice straw through anaerobic digestion (AD) process. The findings suggest that pretreatment with NUr could substantially enhance hydrolysis rates and H₂ production. The maximum biohydrogen production (BHP) yield reached 184.46 mL/g substrate with 86.98 % holocellulose retention yield and 59.84 % removal of lignin when RS was pretreated by NUr at a concentration of 3 % w/v, 20 % solid loading, −12 °C, and 3 months. Macro and microstructure analysis confirmed more cellulose and hemicellulose were exposed due to the lignin removed, and crystallinity decreased after NUr pretreatment. The energy conversion efficiency (ECE) attained via NUr pretreated RS was 10.38 %, exceeded that of raw RS by 62.19 %. These findings offer a promising and efficient pretreatment technology for enhancing the recovery of H₂ from lignocellulosic biomass, yielding both environmental and economic advantages.

Bio-jet fuels are considered as a highly promising strategy for minimizing carbon emissions in the aviation sector. This study presents a scheme for producing bio-jet fuel from corn stover through aqueous phase conversion, focusing on the economics and environmental performance of various lignin utilization technologies. Three scenarios were simulated using Aspen Plus, each integrating a different approach: lignin hydrothermal conversion to jet fuel range arenes (LtoA), lignin gasification-syngas fermentation to ethanol (LtoE), and lignin direct combustion (LC). The energy conversion rates of the three cases are 32.75 %, 32.67 %, and 31.44 %, in that order. Technical-economic analysis and life cycle assessment were conducted for each scenario. The minimum jet fuel selling prices (MJFSP) for the three scenarios range between 2050 and 2562 $/t, 2095–2620 $/t, and 2024–2529 $/t, with greenhouse gas (GHG) emissions reduced by 33 %, 383 %, and 37 % compared to fossil jet fuel, respectively. Steam stripping for furfural production is the largest energy consumer, hindering economic improvement and GHG emission reduction due to inefficient furfural yield. The use of sulfuric acid and NaOH as catalysts contributes significantly to 37 % of greenhouse gas (GHG) emissions and 79 % of human toxicity emissions among other environmental impacts. The development of green solvents and the enhancement of lignin conversion rates could further improve the economic and environmental performance of bio-jet fuel.