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The hydrothermal refinery is a promising thermochemical upgrading technology for high-moisture biomass and wastes. This work aimed to investigate the effect of chloride and propionate anions on hydrochar from hydrothermal carbonization of corn residues. Initial concentrations of ionic salt liquids used as a hydrothermal medium were within 0.33–1.71...
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... as bio-based mesoporous materials and corncob were activated. They were soaked in 0.1 M of phosphoric acid for 2 h and dried in an oven at 80C for 48 h. They were then activated. The activation temperature and time applied were 900C for 2 h at a heating rate of 10C/min under a CO 2 flow rate of 100 mL/min. The procedure is shown schematically in Fig. ...Similar publications
Self-activation is an endothermic process in the form of physical/thermal activation that utilizes the gases produced during the high temperature pyrolysis of a carbonaceous material. This serves as the activation agent resulting in the conversion of the material into activated carbon. Because the pyrolysis happens in a sealed high temperature envi...
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... Specifically, an elevated vapor pressure favors the occurrence of secondary reactions, such as thermal cracking, repolymerization, and recondensation, that lead to the formation of a more coalified and stable solid product [49]. However, this high vapor pressure hinders the critical degradation reactions of biopolymers [50,51] and hemicellulose [52], which are the primary sources of bio-oil. These degradation reactions, which include hydrolysis and decomposition, are essential for converting the biomass into liquid fuels and chemicals. ...
Liquefaction conversion technology has become one of the hottest biomass conversion methods due to its flexible material selection and extensive product applications. Exploring biomass liquefaction conversion focuses on catalysts, biomass/water ratio, and reaction temperature. However, it is found that solvents are crucial in the biomass liquefaction process and significantly impact the type of liquefied products and bio-oil yield. Given the current rapid development trend, timely sorting and summary of the solvent effect in the biomass liquefaction process can promote the subsequent development and industrialization of more efficient and cleaner biomass liquefaction technology. Therefore, this review first introduces the characteristics of water as the liquefaction solvent, then summarizes the effects of organic solvents on liquefaction, and finally elaborates on the synergistic effect of co-solvents, which provides a more systematic overview of solvent effects in the liquefaction process. Meanwhile, prospects are put forward for the future development of biomass liquefaction conversion.
... The catalytic effect of FeCl 3 is bound to its constituents Fe3 + and Cl− (see Fig. 4). Fe3 + promotes the production of Lewis acid sites that would enhance decarboxylation and decarbonylation reactions and catalyze the glucose/ fructose isomerization (Djandja et al., 2023), while Cl-could strongly interact with the end -OH group of monosaccharide units in cellulose enhancing the breaking of inter-and intramolecular hydrogen bonds and thus improving hydrolysis (Srilek et al., 2022). In agreement with Fig. 3.e, the isomerization of glucose/fructose is expected to take place at 110 • C with further formation of HMF via dehydratiation (Djandja et al., 2023). ...
... The catalytic effect of FeCl 3 is bound to its constituents Fe3 + and Cl− (see Fig. 4). Fe3 + promotes the production of Lewis acid sites that would enhance decarboxylation and decarbonylation reactions and catalyze the glucose/ fructose isomerization (Djandja et al., 2023), while Cl-could strongly interact with the end -OH group of monosaccharide units in cellulose enhancing the breaking of inter-and intramolecular hydrogen bonds and thus improving hydrolysis (Srilek et al., 2022). In agreement with Fig. 3.e, the isomerization of glucose/fructose is expected to take place at 110 • C with further formation of HMF via dehydratiation (Djandja et al., 2023). ...
... The improved vapor pressure would further improve the secondary reactions, such as thermal cracking, repolymerization, and recondensation, that would lead to a more coalified and stable solid product [2]. This high vapor pressure may hinder the hydrolysis and degradation of biopolymers [27,33] and hemicellulose [31]. ...
Solvothermal liquefaction of biomass has gained attention to produce liquid biofuel and specialized chemicals. In this study, eXtreme Gradient Boosting was applied for predicting the bio-oil yield during solvothermal liquefaction of lignocellulosic biowaste. To establish a precise model for predicting the bio-oil yield, the prediction of the biomass conversion was found to be an intermediate ameliorating variable. The combination of the contents of biochemical components (cellulose, hemicellulose and lignin) with the operating factors (temperature, time, solid loading, solvent polarity and solvent density) provided the best prediction for the biomass conversion (R2 equals to 99.98% for training and 97.67% for test). To predict the yield of bio-oil, introduction of the biomass conversion among inputs improved prediction accuracy (R2 equals to 100% for training and 94.4% for test). The best prediction models developed were interpreted using a game theory-based feature importance and the partial dependence plotting analysis, which provided insights into the biomass conversion pathways and the bio-oil generation mechanism. To assist other researchers in predicting, a graphical user interface was created. This tool will save both resources and time that would otherwise be spent on multiple experimental trials and might not yield useful results.
... Calcium propionate salt was revealed to help lower the vapour pressure of the hydrothermal carbonization medium and degrade hemicellulose through the interaction of CH 3 CH 2 COO − anion with the strong inter-and intra-hydrogen bonds of monosaccharide units (Srilek et al., 2022). The hydrolysis rate of the HTC process with calcium propionate salt occurred via the H + and OH − from the water reaction medium and OH − from the calcium propionate salt. ...
... Glucose may also undergo isomerization, dehydration, and oxidation to produce acetic acid which may also catalyze the process. On the other hand, the end -OH group of monosaccharide units in cellulose and hemicellulose can interact strongly with Cl-, enhancing the breaking of inter-and intramolecular hydrogen bonds in these substances (Srilek et al., 2022). Hence, Cl − would improve the hydrolysis of the feedstock by penetrating the polysaccharide layer and cleaving the ether linkages. ...
... Besides the acidic FeCl 3 , some neutral chloride salts are also explored. NaCl has been found to lower the vapour pressure in the hydrothermal carbonization reaction medium (Srilek et al., 2022), leading to improved hydrolysis of biopolymers (Ma et al., 2021b;Xu et al., 2020b) and the degradation of hemicellulose (Srilek et al., 2022). However, when the temperature was increased during sewage sludge processing, this catalyst improved the heterocyclic-N in the hydrochar via the solidification reaction of nitrogen in the liquid phase (Ma et al., 2021b;Xu et al., 2020b). ...
Hydrothermal carbonization has gained attention in converting wet organic solid waste into hydrochar with many applications such as solid fuel, energy storage material precursor, fertilizer or soil conditioner. Recently, various catalysts such as organic and inorganic catalysts are employed to guide the properties of the hydrochar. This review presents a summarize and a critical discussion on types of catalysts, process parameters and catalytic mechanisms. The catalytic impact of carboxylic acids is related to their acidity level and the number of carboxylic groups. The catalysis level with strong mineral acids is likely related to the number of hydronium ions liberated from their hydrolysis. The impact of inorganic salts is determined by the Lewis acidity of the cation. The metallic ions in metallic salts may incorporate into the hydrochar and increase the ash of the hydrochar. The selection of catalysts for various applications of hydrochars and the environmental and the techno-economic aspects of the process are also presented. Although some catalysts might enhance the characteristics of hydrochar for various applications, these catalysts may also result in considerable carbon loss, particularly in the case of organic acid catalysts, which may potentially ruin the overall advantage of the process. Overall, depending on the expected application of the hydrochar, the type of catalyst and the amount of catalyst loading requires careful consideration. Some recommendations are made for future investigations to improve laboratory-scale process comprehension and understanding of pathways as well as to encourage widespread industrial adoption.
In the last few decades, global warming, environmental pollution, and an energy shortage of fossil fuel may cause a severe economic crisis and health threats. Storage, conversion, and application of regenerable and dispersive energy would be a promising solution to release this crisis. The development of porous carbon materials from regenerated biomass are competent methods to store energy with high performance and limited environmental damages. In this regard, bio-carbon with abundant surface functional groups and an easily tunable three-dimensional porous structure may be a potential candidate as a sustainable and green carbon material. Up to now, although some literature has screened the biomass source, reaction temperature, and activator dosage during thermochemical synthesis, a comprehensive evaluation and a detailed discussion of the relationship between raw materials, preparation methods, and the structural and chemical properties of carbon materials are still lacking. Hence, in this review, we first assess the recent advancements in carbonization and activation process of biomass with different compositions and the activity performance in various energy storage applications including supercapacitors, lithium-ion batteries, and hydrogen storage, highlighting the mechanisms and open questions in current energy society. After that, the connections between preparation methods and porous carbon properties including specific surface area, pore volume, and surface chemistry are reviewed in detail. Importantly, we discuss the relationship between the pore structure of prepared porous carbon with surface functional groups, and the energy storage performance in various energy storage fields for different biomass sources and thermal conversion methods. Finally, the conclusion and prospective are concluded to give an outlook for the development of biomass carbon materials, and energy storage applications technologies. This review demonstrates significant potentials for energy applications of biomass materials, and it is expected to inspire new discoveries to promote practical applications of biomass materials in more energy storage and conversion fields.
