Optimization of the soda-ethanol delignification stage for a rice husk biorefinery

Dagnino, Eliana Paola; Felissia, Fernando Esteban; Chamorro, Ester; Área, María Cristina

doi:10.1016/j.indcrop.2016.12.016

Cited by 34 publications

(13 citation statements)

References 41 publications

(35 reference statements)

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“…• Aryglycerol β-aryl ether with β-O-4 links (label A), which can be seen at δ C -δ H : 72.5/4.9 and 71.8/4.7 (C α -H α in S and G-units respectively), 84.4/4.3 and 86.5/4.1 (C β -H β in S and G-units, respectively) and a broad signal, overlapping with others, in 60.2/3.7-60. 4 Finally, it is worth mentioning that the presence of associated carbohydrate signals, which are indicated in the figure corresponding to the anomeric positions and some other with acetyl substituents [39]. Table S2 (Supplementary Material) collects the assignments of the 13 C-1 H correlation signals in the HSQC NMR spectrum of the obtained lignin fractions.…”

Section: H-13 C Hsqc Nmr Spectroscopy Of Ligninsmentioning

confidence: 99%

“…In this scenario, lignocellulosic materials are promising candidates as feedstock to obtain biofuels, building blocks, bio-chemicals, food additives, adhesives, or cosmetics, among others [3,4]. Lignocellulosic materials (LCM) present a three-dimensional and recalcitrant structure mainly composed of cellulose (homopolymer made up of glucose units), hemicelluloses (heteropolymer made up of different sugars) and lignin (aromatic polymer).…”

Section: Introductionmentioning

confidence: 99%

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Formosolv Pretreatment to Fractionate Paulownia Wood Following a Biorefinery Approach: Isolation and Characterization of the Lignin Fraction

Domínguez¹,

Río

Romaní

et al. 2020

Agronomy

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Paulownia is a rapid-growth tree with a high biomass production rate per year and low demand of water, which make it very suitable for intercropping systems, as it protects the crops from adverse climatic conditions, benefiting the harvest yields. Moreover, these characteristics make Paulownia a suitable raw material able to be fractionated in an integrated biorefinery scheme to obtain multiple products using a cascade conversion approach. Different delignification pretreatments of biomass have been purposed as a first stage of a lignocellulosic biorefinery. In this study, the formosolv delignification of Paulownia wood was investigated using a second order face-centered factorial design to assess the effects of the independent variables (concentrations of formic and hydrochloric acids and reaction time) on the fractionation of Paulownia wood. The maximum delignification achieved in this study (78.5%) was obtained under following conditions: 60 min, and 95% and 0.05% formic and hydrochloric acid, respectively. In addition, the remained solid phases were analyzed to determine their cellulose content and cooking liquors were also chemically analyzed and characterized. Finally, the recovered lignin by precipitation from formosolv liquor and the pristine lignin (milled wood lignin) in Paulownia wood were characterized and compared by the following techniques FTIR, NMR, high-performance size-exclusion chromatography (HPSEC) and TGA. This complete characterization allowed verifying the capacity of the formosolv process to act on the lignin, causing changes in its structure, which included both phenomena of depolymerization and condensation.

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Section: H-13 C Hsqc Nmr Spectroscopy Of Ligninsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Formosolv Pretreatment to Fractionate Paulownia Wood Following a Biorefinery Approach: Isolation and Characterization of the Lignin Fraction

Domínguez¹,

Río

Romaní

et al. 2020

Agronomy

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“…Comparing with previous studies using other organic solvents for rice husk delignification, this suggests that the ethanol-sulfuric acid solvent is more effective. For example, in other studies using 1,4-butanediol [18] and ethanol-soda [28] as organic solvents for rice husk delignification, 86.0% and 90.1% delignification yields were obtained, respectively. However, these two processes require acid hydrolysis pretreatment, which leads to process complexity and economic penalties.…”

Section: Delignification Behaviormentioning

confidence: 99%

Reaction Characteristics of Organosolv-Fractionation Process for Selective Extraction of Carbohydrates and Lignin from Rice Husks

Kim

Kwak²,

Kim

et al. 2021

Energies

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The organosolv-fractionation process can act as a biorefinery process because it can separate the main components of biomass, such as lignin and hemicellulose, with high purity. The ethanol-based organosolv-fractionation process was applied to separate carbohydrates and lignin from rice husks, and the extraction behavior was observed according to various reaction variables. Various reaction conditions such as different temperatures (150 °C, 170 °C, and 190 °C), reaction times (30 min, 60 min, and 120 min), and ethanol concentrations (40%, 60%, and 80%) were tested while maintaining the solid:liquid ratio (1:10) and sulfuric acid concentration (0.25 wt.%). Two optimal reaction conditions for the target components were chosen: for sugar recovery, 150 °C, 60 min, and 40% ethanol were used as condition 1, and for lignin recovery, 170 °C, 120 min, and 80% ethanol were used as condition 2. Under condition 1, 91.5% of the glucan was preserved in the residual solid, and 75.0% of the xylan was extracted from the liquid hydrolysate. For condition 2, 59.9% of the lignin was recovered. To properly choose and apply the correct fractionation method and conditions, the reaction behavior (such as carbohydrate retention and extraction), lignin solubilization, and precipitation should be carefully considered.

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“…13 and 14) led to improved delignification degrees. In related studies, alkaline-organosolv methods were successfully applied to rice husks [35,36]. Native and pretreated sugarcane bagasse were also delignified by alkaline-organosolv delignification, resulting in a significantly higher lignin removal in the native samples [38,39].…”

Section: Delignification Treatmentsmentioning

confidence: 99%

Development of Pretreatment Strategies for the Fractionation of Hazelnut Shells in the Scope of Biorefinery

et al. 2020

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Hazelnut shells are an important waste from the hazelnut processing industry that could be valorized in a multi-product biorefinery. Individual or combined pretreatments may be integrated in processes enabling the integral fractionation of biomass. In this study, fractionation methods based on alkaline, alkaline-organosolv, organosolv, or acid-catalyzed organosolv treatments were applied to raw or autohydrolyzed hazelnut shells. A comparative analysis of results confirmed that the highest lignin removal was achieved with the acid-catalyzed organosolv delignification, which also allowed limited cellulose losses. When this treatment was applied to raw hazelnut shells, 65.3% of the lignin was removed, valuable hemicellulose-derived products were obtained, and the cellulose content of the processed solids increased up to 54%. Autohydrolysis of hazelnut shells resulted in the partial solubilization of hemicelluloses (mainly in the form of soluble oligosaccharides). Consecutive stages of autohydrolysis and acid-catalyzed organosolv delignification resulted in 47.9% lignin removal, yielding solids of increased cellulose content (55.4%) and very low content of residual hemicelluloses. The suitability of selected delignified and autohydrolyzed-delignified hazelnut shells as substrates for enzymatic hydrolysis was assessed in additional experiments. The most susceptible substrates (from acid-catalyzed organosolv treatments) reached 74.2% cellulose conversion into glucose, with a concentration of 28.52 g glucose/L.

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Optimization of the soda-ethanol delignification stage for a rice husk biorefinery

Cited by 34 publications

References 41 publications

Formosolv Pretreatment to Fractionate Paulownia Wood Following a Biorefinery Approach: Isolation and Characterization of the Lignin Fraction

Formosolv Pretreatment to Fractionate Paulownia Wood Following a Biorefinery Approach: Isolation and Characterization of the Lignin Fraction

Reaction Characteristics of Organosolv-Fractionation Process for Selective Extraction of Carbohydrates and Lignin from Rice Husks

Development of Pretreatment Strategies for the Fractionation of Hazelnut Shells in the Scope of Biorefinery

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