超声作用木质化硅化，促进提取

For a sustainable biorefinery, reduction in the recalcitrance of lignocellulosic biomass is very crucial for the efficient utilization of each fraction. The present work investigated an integrated pretreatment method to recover high-quality lignin along with the cellulose-rich pulp. An optimization study employing response surface methodology studied the synergistic effects of ultrasound and organosolv pretreatment from Bambusa tulda (bamboo). The optimal condition (180 °C, 55 min, and 30 min sonication) resulted in 65.81±2.40% of lignin yield with 95.37± 1.17% purity. A reduction in 7.85% yield and 1.54% purity of lignin with organosolv pretreatment highlighted the efficacy of sonication in lignin extraction. Ultrasound resulted in homolytic cleavage of the lignin-carbohydrate bond that enhanced delignification and increase the cellulose crystallinity. NMR, FTIR, GPC, and TGA of lignin suggested the superiority of sonication in maintaining lignin quality. A significant amount of β-O-4 linkages in extracted lignin is favorable for its subsequent valorization.

… been carried out to extract lignin with ultrasound from various … to sequentially extract lignin from sugar cane bagasse, the lignin … without ultrasound treatment [9]. During the process of …

The process of cellulose and lignin extraction from Vietnam’s rice straw without paraffin pretreatment was proposed to improve economic efficiency and reduce environmental pollution. Treatment of the rice straw with ultrasonic irradiation for 30 min increased yields of lignin separation from 72.8% to 84.7%. In addition, the extraction time was reduced from 2.5 h to 1.5 h when combined with ultrasonic irradiation for the same extraction yields. Results from modern analytical methods of FT-IR, SEM, EDX, TG-DTA, and GC-MS indicated that lignin obtained by ultrasound-assisted alkaline treatment method had a high purity and showed a higher molecular weight than that of lignin extracted from rice straw without ultrasonic irradiation. The lignin and cellulose which were extracted from rice straw showed higher thermal stability with 5% degradation at a temperature of over 230°C. The ultrasonic-assisted alkaline extraction method was recommended for lignin and cellulose extraction from Vietnam’s rice straw.

… Unfortunately, the yield of isolated lignin for the ethanol extraction … extraction efficiency of lignin from poplar, ultrasound was used to assist the ethanol extraction and the isolated lignin …

… However, the use of ultrasound for direct extraction of lignin polymer from straw or wood has not been reported. The aim of this study was to compare the yield, composition, physico-…

… by using the ultrasound-assisted time for 30 min. The percentage yield and purity of lignin extracted by the ultrasound-assisted alkali method was higher than that lignin fraction which …

Ultrasound-assisted method is claimed as a simpler and more effective ways of extracting compared to conventional extraction methods for the extraction of bioactive compounds from natural products such as lignin. This study investigated the potential of ultrasound-assisted extraction to extract lignin from oil palm frond (OPF) as compared to conventional heating. The extraction had been carried out by using sodium hydroxide solution as a solvent. Factors such as extraction temperature and solvent concentration were also examined. The presences of lignin in the corresponding extracts were confirmed by FTIR analysis. The result obtained showed that the extraction of OPF assisted with ultrasound was more efficient in giving higher lignin yield compared to conventional heating. Other than that, the reaction temperature was lowered down and the reaction time was also shortened when the extraction was assisted by ultrasound. With all these merits, ultrasound-assisted extractions were more effective to be used and should be considered for a wider application in the extraction of lignin and other compounds from various plants.

In this study, lignin was extracted using ultrasonic and then, by the gelation-solidification method. The extracted lignin was used as reinforcement for the synthesis of a novel biocomposite as biosorbent for removal of lead heavy metal from aqueous solutions. The structural and chemical characteristics of biocomposite were determined by FESEM, EDX, FTIR, and BET analyses, respectively. Biocomposite beads were used as an efficient adsorbent in the lead removal process from aqueous solutions in different conditions. Also, point zero charge studies and the effective parameters on adsorption such as contact time, pH, temperature and initial concentration, kinetics, isotherms, and thermodynamics of the adsorption, and adsorbent regeneration and reuse were investigated. The maximum experimental adsorption capacity of the adsorbent was obtained 365.43 mg·g-1 at C0 = 210 mg/L, T = 328 K, and pH = 5. The experimental kinetic and equilibrium data were well adjusted with pseudo-second-order kinetic models and Freundlich isotherm models, respectively, according to linear regression (R2), chi-square statistic (χ2), and the sum of the squares of the errors (SSE). The thermodynamics parameters were analyzed and the results showed an endothermic and spontaneous adsorption process. Regeneration and reuse results of the synthesized biocomposite represented highly adsorption efficiency after five adsorption cycle stages.

Extracting The extraction of cellulose and lignin from biomass is essential for the development of sustainable bio-based materials. This study examines the effects of physical pretreatment techniques-ultrasound (US), pulsed electric fields (PEF), and high-voltage electrical discharges (HVED)-on the efficiency of alkali treatment for cellulose and lignin extraction from walnut shells. The primary objective was to enhance extraction yields and improve extract quality while evaluating the effectiveness of these methods. The results revealed that the combined treatments achieved lignin and cellulose yields of up to 17.03 % and 33.40 %, respectively, with US and HVED showing significantly higher extraction efficiencies compared to other techniques. Characterization of the extracted materials using FTIR, XRD, 2D HSQC NMR, TGA/DTG, and DSC confirmed the presence of key functional groups, crystalline structures, and detailed molecular features, while also providing insights into thermal stability. These findings underscore the potential of walnut shells as a sustainable source for bio-based materials and demonstrate the influence of physical pretreatments on the structural and thermal properties of extracted cellulose and lignin. This study paves the way for further research into industrial applications, such as wood adhesives. Future work should focus on optimizing extraction processes, scaling up operations, and investigating the effects of biomass variability on extraction outcomes.

… The results showed that ultrasounds cleaved lignin–… affected to insoluble lignin content (19% of Klason lignin solubilisation). … the extraction of natural components was microwave- or …

Lignin isolated from Miscanthus×giganteus using acidic (FAL… The characterization of lignin samples was achieved by … to the procedure used for the extraction of lignin. In all the reactions …

… After an exhaustive literature review, no studies have been found that describe the use of the DES employed in this work combined with pH 13 and ultrasound for lignin extraction from …

… Ultrasound energy was used to increase lignin extraction yield and purity or to remove the major inorganic load from the alkali lignin … induced by ultrasound treatments onto lignins we …

Abstract A low-cost and green biorefinery will increase the economy and revenue from lignocellulosic biomass. This study demonstrated the effect of two-pot sequential pretreatment, comprising of ultrasound ethanol (USEL) synergized ternary deep eutectic solvent (TDES, choline chloride: glycerol: FeCl3·6H2O), with the aim to investigate the effects of USEL, TDES, and USEL + TDES pretreatments on enhancing delignification of sugarcane bagasse (SCB). The results showed that under the optimum TDES pretreatment conditions (FeCl3·6H2O, 120 °C, 3 h), the cellulose content and lignin removal rate (LRR) of SCB reached 47.67 and 82.71%, respectively. Under the optimum synergy conditions (USEL conditions: 100% ethanol, 20 + 28 + 40 kHz, 240 W, 60 min; TDES conditions: FeCl3·6H2O, 120 °C, 3 h), the cellulose content and LRR of SCB reached 66.17 and 86.39%, respectively. After enzymatic hydrolysis, the SCB pretreated with USEL + TDES shows a saccharification rate of 90.31%, which was substantially higher than that of the SCB pretreated with TDES alone (85.68%). X-ray diffraction, particle size, brunauer-emmet-teller, scanning electron microscopy, and optical microscopy analyses were conducted to confirm the efficiency of USEL + TDES on pretreating SCB. Meanwhile, 2D-HSQC NMR analysis revealed that regenerated lignin exhibited well-preserved structures (β-O-4, β-β linkages), making it suitable for depolymerization into monoaromatic compounds. Overall, this work demonstrated that biomass pretreatment with the USEL + TDES was promising for a low-cost biorefinery to efficiently fractionate lignocellulosic biomass into glucose and high-quality lignin with tailored chemical structures.

The efficient and high-value utilization of lignin is crucial for advancing sustainable biorefining technologies. Conventional lignin separation methods often lead to the cleavage of β-O-4 linkages, resulting in dark-colored, highly condensed lignin with limited applicability in downstream industries. To overcome this limitation, an ultrasonic- and alkali-assisted ethanol extraction (UASE80) method was developed that enables efficient isolation of light-colored, low-condensed, and highly reactive lignin from poplar wood at ambient temperature. The extracted lignin retains a significant portion of β-O-4 bonds (53.5/100Ar), representing 90.3 % of the raw content, with a yield of 45.17 % and a purity of 99.9 %. After nanotechnology processing, the resulting lignin nanoparticles exhibit excellent UV-shielding performance. With only 10 wt% addition, they increase the Sun Protection Factor (SPF) of a pure cream from 1.04 to 20.13, while maintaining desirable sensory characteristics and compatibility with natural skin tones. This work offers a green and efficient strategy for producing high-quality, functionally enriched lignin, underscoring its promising potential for high-value applications in cosmetics and functional materials.

This study demonstrated the effect of two-pot sequential pretreatment, comprising of ultrasound assisted deep eutectic solvent (DES) with the aim to investigate the effects of ultrasound amplitude and duration in enhancing delignification. Oil palm fronds (OPF) were ultrasonicated in a water medium, followed by a pretreatment using DES (choline chloride:urea). Fourier transform infra-red spectroscopy, X-ray diffraction, field emission scanning electron microscope, Brunauer-Emmet-Teller and solubilised lignin concentration were conducted to confirm the effectiveness of ultrasound assisted DES on the pretreatment of OPF. The recommended ultrasound conditions were determined to be 70% amplitude and duration of 30 min, where the sequential DES pretreatment was able to reduce lignin content of OPF to 14.01%, while improving xylose recovery by 58%.

… , ultrasound-assisted DES pretreatment was used to treat cotton straw, which could retain most of the cellulose in cotton straw and separate hemicellulose and lignin … extraction of lignin. …

Ultrasound-assisted extraction of hemicellulose and phenolic compounds from bamboo bast fibre powder was investigated. The effect of ultrasonic probe depth and power input parameters on the type and amount of products extracted was assessed. The results of input energy and radical formation correlated with the calculated values for the anti-nodal point (λ/4; 16.85 mm, maximum amplitude) of the ultrasonic wave in aqueous medium. Ultrasonic treatment at optimum probe depth of 15 mm improve 2.6-fold the extraction efficiencies of hemicellulose and phenolic lignin compounds from bamboo bast fibre powder. LC-Ms-Tof (liquid chromatography-mass spectrometry-time of flight) analysis indicated that ultrasound led to the extraction of coniferyl alcohol, sinapyl alcohol, vanillic acid, cellobiose, in contrast to boiling water extraction only. At optimized conditions, ultrasound caused the formation of radicals confirmed by the presence of (+)-pinoresinol which resulted from the radical coupling of coniferyl alcohol. Ultrasounds revealed to be an efficient methodology for the extraction of hemicellulosic and phenolic compounds from woody bamboo without the addition of harmful solvents.

… cellulose and lignin at 80 C, removing 80% of the lignin and … an increase of lignin purity, the lignin extraction has been assisted by … Ultrasonic-assisted extraction, an eco-friendly and …

Highlights • US-assisted solubilization of hydrolysis lignin in mild alkaline conditions.• US effect up to 30 % in mild conditions with 20 kHz.• Induces the inclusion of high MW fractions into the solution.• Involves the mechanoacoustical and sonochemical effects of US.• NMR shows increased OH groups in the obtained fractions.

The development of food industry technologies and increasing the sustainability and effectiveness of processing comprise some of the relevant objectives of EU policy. Furthermore, advances in the development of innovative non-thermal technologies can meet consumers’ demand for high-quality, safe, nutritious, and minimally processed foods. Acoustic technology is characterized as environmentally friendly and is considered an alternative method due to its sustainability and economic efficiency. This technology provides advantages such as the intensification of processes, increasing the efficiency of processes and eliminating inefficient ones, improving product quality, maintaining the product’s texture, organoleptic properties, and nutritional value, and ensuring the microbiological safety of the product. This review summarizes some important applications of acoustic technology in food processing, from monitoring the safety of raw materials and products, intensifying bioprocesses, increasing the effectiveness of the extraction of valuable food components, modifying food polymers’ texture and technological properties, to developing biodegradable biopolymer-based composites and materials for food packaging, along with the advantages and challenges of this technology.

In this work, intensification of the enzymatic hydrolysis of cellulose was investigated using a high multi-frequency ultrasonic reactor, and the effects of ultrasound on enzyme stability were addressed. The influence of ultrasound on glucose yields was evaluated using Avicel microcrystalline cellulose and cellulase + cellobiase enzymes at 50 °C and pH 5.2. The structure of the treated cellulose was studied using Brunauer–Emmett–Teller (BET) and X-ray diffraction (XRD). The overall effect of ultrasound was dependent upon parameters such as energy input, frequency, and irradiation duration. The best hydrolysis results occurred at 611 kHz and 104 W, with 50% and up to 70% glucose yield in 24 h and 40–50 h, respectively. The results indicated that the effect of ultrasound was mainly physical in nature. Ultrasound-induced cellulose fragmentation resulted in a surface area increase and crystallinity reduction, which increased mass transfer and, hence, the intensification of enzymatic hydrolysis leading to increased glucose yield. Overall, it appears that ultrasound and/or cavitation-assisted technologies are green techniques that have the potential to enhance hydrolysis of lignocellulosic materials for biofuel production and biorefinery applications; through physical and/or chemical mechanisms, and with little or no effect on the specific activity of the complex enzyme at typical treatment conditions.

… of lignin in ultrasonic pretreatment. Furthermore ultrasonic pretreatment of corn stover improved hydrolysis yields, alongside a decrease in lignin content. (64) Delignification with …

… lignin, or the removal of the latter. At the selected optimum parameters of ultrasonic pretreatment … dry substance) while that of lignin is 11.4 % of ads Pretreatment of a substrate with ultra …

… ultrasound-assisted DES pretreatment could be a promising alternative pretreatment technique for lignocellulosic … in cleaving the lignin-carbohydrate complexes in lignocellulose, which …

… ultrasonic treatment. Therefore, the ultrasonically assisted alkali pretreatment can improves the degradation rate of lignin … The mechanism of the effect of ultrasonic waves on the enzy…

… lignin from the samples; the pretreatment … lignin, and the highly crystalline nature of said cellulose are two main factors that increase the cost associated with processing lignocellulosic …

… production of lignocellulose lies in the biorefinery of lignin, … effects of distinct kinds of lignocellulose raw materials, distinct … by microwave ultrasound on the pretreatment of …

… The study was conducted on three lignocellulosic biomass … , exploiting ultrasound for the pretreatment of lignocellulosic … (moj) of the lignin present in the naive lignocellulosic fiber with …

Pretreatment of lignocellulosic biomass to overcome its intrinsic recalcitrant nature prior to the production of valuable chemicals has been studied for nearly 200 years. Research has targeted eco-friendly, economical and time-effective solutions, together with a simplified large-scale operational approach. Commonly used pretreatment methods, such as chemical, physico-chemical and biological techniques are still insufficient to meet optimal industrial production requirements in a sustainable way. Recently, advances in applied chemistry approaches conducted under extreme and non-classical conditions has led to possible commercial solutions in the marketplace (e.g. High hydrostatic pressure, High pressure homogenizer, Microwave, Ultrasound technologies). These new industrial technologies are promising candidates as sustainable green pretreatment solutions for lignocellulosic biomass utilization in a large scale biorefinery. This article reviews the application of selected emerging technologies such as ionizing and non-ionizing radiation, pulsed electrical field, ultrasound and high pressure as promising technologies in the valorization of lignocellulosic biomass.

… lignin from lignocellulose, mild pretreatment conditions using p-TsOH and a subsequent 10 s ultrasonic treatment for the pretreated … Under the same pretreatment conditions as shown in …

Abstract Efficient fermentable sugar release from softwood biomass is considerably hampered by the recalcitrant nature of its plant cell wall. Here, we reported an ultrasonic and microwave assisted ethylene glycol pretreatment coupled with fast pyrolysis to make total utilization of softwood (pine sawdust) for pyrolytic sugar (levoglucosan), hemicellulosic sugar and phenol production. Compared with oil bath heating, fractionation of pine sawdust into cellulose rich fraction, hemicellulosic sugars and organosolv lignin was enhanced drastically after applying ultrasonic and microwave heating. Whereas, ultrasonic radiation prior to microwave heating turned out to slightly inhibit the fractionation due to oxygenation of sulfuric acid. Mechanistic insight into levoglucosan formation pathway revealed that microwave heating promoted the cleavage of covalent bonds, aromatic ether linkages and glycosidic bonds in lignocellulose, leading to significant improvement in biomass recalcitrance alleviation as well as alkaline and alkaline earth metal removal. This considerably facilitated the heterolytic cleavage of cellulose into levoglucosan, while inhibiting the formation of microorganism inhibitors (e.g. carboxylic acids and phenols) and other light oxygenates in the pyrolysate. Levoglucosan yield exhibited a drastic increase from 3.53 (pine sawdust) to 48.13 wt.% via single microwave heating at 240 W, which was further enhanced with increasing microwave power. Hemicellulosic sugar derived from organosolvolysis and phenol from fast pyrolysis of organosolv lignin also showed an increase in yields with increasing pretreatment severity. Ethylene glycol pretreatment via single microwave heating at 480 W was a preferable process for achieving high yields of levoglucosan (55.87 wt.%), hemicellulosic sugars (19.96 wt.%) and phenols (14.04 wt.%). These findings help to provide an efficient process for maximizing the conversion of recalcitrant softwood for the production of fermentable sugars and phenols.

… (2) Conversion of lignocellulosic biomass into bioethanol consists of the … pretreatment of lignocellulose to reduce recalcitrance in the lignocellulose by removing hemicellulose and lignin…

Currently, in the context of biorefinery and bioeconomy, lignocellulosic biomass is increasingly used to produce biofuels, biochemicals and other value-added products. Microwaves and ultrasound are emerging techniques that enable efficient and environmentally sustainable routes in the transformation of lignocellulosic biomass. This review presents some of the most important works published in the last few years on the application of microwaves and/or ultrasound in lignocellulosic materials pretreatment and can be used as a starting point for research into this theme. This review is divided into four parts. In Part I, the theoretical fundamentals of microwave and ultrasound treatments are reviewed. Dielectric constants for biomass, factors that influence pretreatment, are some of the subjects addressed. In Part II, the effects that these techniques have on lignocellulosic biomass (on the size and surface area of the particle; on the content of lignin, hemicellulose and cellulose; on the crystallinity index of cellulose; on the effect of solubilization of organic matter; on hydrolysis and reduction of sugars) are discussed. In Part III, emphasis is given to the contribution of microwaves and ultrasound in obtaining value-added products. In this context, several examples of liquefaction and extraction procedures are presented. Part IV describes examples of performing sonocatalysis on lignocellulosic biomass to obtain value-added products, such as furfural, whose production is significantly reduced by ultrasound treatment.

… Oil palm frond (OPF) is one of the most abundant lignocellulosic … lignin removal was significantly improved to 47.00 % in comparison to that obtained without ultrasound pretreatment…

In recent years, research is focused on finding a sustainable and eco-friendly lignocellulosic biomass for the effective production of bioethanol to meet the world's energy demand. The present study investigates the bioethanol production potential of four different lignocellulosic biomass residues viz., Saccharum arundinaceum (hardy sugar cane), Arundo donax (giant reed), Typha angustifolia (narrow-leaved cattail), and Ipomoea carnea (pink morning glory). The maximum reducing sugar release showed 185.00 ± 1.57, 213.73 ± 3.47, 187.57 ± 2.14, 294.08 ± 3.98 mg/g and fermentation efficiency of 72.60 ± 8.17%, 82.59 ± 7.42%, 77.45 ± 7.35%, and 85.04 ± 8.37% which was analyzed by estimating the percentage of bioethanol yield were achieved for Saccharum arundinaceum, Arundo donax, Typha angustifolia, and Ipomoea carnea, respectively. The chemical composition of biomass was characterized using National Renewable Energy Limited (NREL) protocol. The effect of ultrasound (US)-assisted alkaline pre-treatment on the four biomasses was characterized by different techniques. The cavitation phenomena of US-assisted alkaline pre-treatment was evident from the decreased value of lignin percentage, increased surface porosity and area, changes in crystallinity index (CrI) values and in the functional groups of biomass. The results revealed that all the four lignocellulosic biomass residues could be utilized as an effective and sustainable source for the production of bioethanol using US-assisted sodium hydroxide as a pre-treatment tool.

Forest biorefineries provide multiple new avenues for applied research. The main concept lies in the malleability of the processes and their stepwise organization. The core element of the biorefinery concept addressed in the present study is the pretreatment step; here, wood biomass is converted into free hemicellulosic sugars, lignin and cellulose. In traditional approaches, the pretreatment step is a starting point for isolating and separating lignin or cellulose through different processes. In this study, instead of performing any separation, a lignin-cellulose mixture was used as its own material, and the effects of ultrasound treatment with a probe system at 20 kHz, with various amplitude, sonication time and dry matter content were investigated with the aim of assessing the formation of a nanocellulose structure with a high lignin content (>30 %) and investigating the stability of the lignin-cellulose mixture under aqueous conditions. We demonstrated the importance of dry matter content for the specific particle size and water retention values for this mixture. US treatment of lignin-cellulose mixtures <4 % dry matter formed a gel-like material, with low particle size (90 % below 30 μm and smallest at nanoscale). Low dry matter loading led to better US transfer and higher conversion of cellulose to <100 nm nanoparticles. Our study can serve as a baseline for future developments in the field of stable emulsions, filtering materials or inputs for material synthesis.

The mass transfer limitation of biopretreatment (BAC) of rice straw biomass can be improved by a delignification process prior to BAC for energy efficient biomethane recovery.

Plants undergo substantial biomineralization of silicon, which is deposited primarily in cell walls as amorphous silica. The mineral formation could be moderated by the structure and chemistry of lignin, a polyphenol polymer that is a major constituent of the secondary cell wall. However, the reactions between lignin and silica have not yet been well elucidated. Here, we investigate silica deposition onto a lignin model compound. Polyphenyl propanoid was synthesized from coniferyl alcohol by oxidative coupling with peroxidase in the presence of acidic tetramethyl orthosilicate, a silicic acid precursor. Raman, Fourier transform infrared, and X-ray photoelectron spectroscopies detected changes in lignin formation in the presence of silicic acid. Bonds between the Si–O/Si–OH residues and phenoxyl radicals and lignin functional groups formed during the first 3 h of the reaction, while silica continued to form over 3 days. Thermal gravimetric analysis indicated that lignin yields increased in the presence of silicic acid, possibly via the stabilization of phenolic radicals. This, in turn, resulted in shorter stretches of the lignin polymer. Silica deposition initiated within a lignin matrix via the formation of covalent Si–O–C bonds. The silica nucleants grew into 2–5 nm particles, as observed via scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy. Additional silica precipitated into an extended gel. Collectively, our results demonstrate a reciprocal relation by which lignin polymerization catalyzes the formation of silica, and at the same time silicic acid enhances lignin polymerization and yield.

… the silicified waxy surface, break down lignin–hemicellulose complex, partially remove silicon and lignin, … They found that the use of ultrasound in the liquefaction process inhibited the …

Agricultural and forest residues obtained after harvesting are promising renewable sources, suitable as a source of pulp for cellulose nanocrystal manufacturing. Cavitation-assisted …

Rice husk contains various components, such as cellulose, hemicellulose, lignin, pectin, and silica. Therefore, this study introduces a novel integrated process for the complete …

… The effect of ultrasound on lignocellulosic biomass … silica deposition on OPEFB fibre is known as a hindrance to acid penetration. The current study indicated a notable decrease of silica …

… husks contain nearly 20 mass% silica, which is present in … a consequence, the deposition thickness strongly depended … an ultrasonic-assisted sol–gel method [157] using an ultrasonic…

Abstract Lignin is an abundant heterogeneous aromatic biopolymer in the nature with a complex and an irregular structure and very low solubility in common solvents. Such drawbacks limit lignin isolation from wood and its conversion to value-added products. Here, for the first time we report a very high solubility of lignin in the very economic and green deep eutectic solvents using ultrasound irradiation. We synthesized a series of deep eutectic solvent based on the possible favorable solute-solvent interactions. It was found that lignin can be solubilized in these solvents up to about 50% w/w. To the best of our knowledge, this is the highest amount of any lignocellulosic compound solubility which has been reported to this time. Moreover, due to the low solubility of cellulose in these deep eutectic solvents, lignin can be completely isolated from lignocellulosic biomass in one-pot procedure. We think that this exploration can open new promising window to lignin-based science and technology.

The fractionation of components of lignocellulosic biomass is important to be able to take advantage of biomass resources. The hydrothermal–ethanol method has significant advantages for fraction separation. The first step of hydrothermal treatment can separate hemicellulose efficiently, but hydrothermal treatment affects the efficiency of ethanol treatment to delignify lignin. In this study, the efficiency of lignin removal was improved by an ultrasonic-assisted second-step ethanol treatment. The effects of ultrasonic time, ultrasonic temperature, and ultrasonic power on the ultrasonic ethanol treatment of hydrothermal straw were investigated. The separated lignin was characterized by solid product composition analysis, FT-IR, and XRD. The hydrolysate was characterized by GC-MS to investigate the advantage on the products obtained by ethanol treatment. The results showed that an appropriate sonication time (15 min) could improve the delignification efficiency. A proper sonication temperature (180 °C) can improve the lignin removal efficiency with a better retention of cellulose. However, a high sonication power 70% (840 W) favored the retention of cellulose and lignin removal.