High Hemicellulose Research Articles

The Effect of Time, Ph and Starter Concentration on Bioethanol Content in the Tobacco Stem Fermentation Process

The depletion of fossil fuels has now occurred in various parts of the world. Meanwhile, the demand for fuel energy continues to increase. This condition encourages researchers to look for alternative fuels with high availability of raw materials. Bioethanol is an environmentally friendly renewable energy with biomass production raw materials, it can be an alternative solution to replace fuel oil. One of the biomass that has the potential to be used as a raw material for bioethanol production is tobacco. Tobacco stems have high cellulose and hemicellulose content so that they can be used in bioethanol production. This research method uses base pretreatment and base hydrolyzate, then fermentation and distillation processes are carried out. The results of tobacco stem bioethanol were analyzed using the Response Surface Methodology (RSM) approach, Central Composite Design (CCD) model. During the fermentation process, three independent variables were used, namely the fermentation time of 72-168 hours, pH 4-5, and starter concentration of 0.1% - 0.3%. The results of the Analysis of Variance (ANOVA) of ethanol content showed that the significant variables were the fermentation time and starter concentration. The results of the CCD analysis were obtained at optimum time conditions of 120 hours, pH 4.5 and starter concentration of 0.2% with a bioethanol content of 23.007%.

Co-pyrolysis of corn stalk and high-density polyethylene with emphasis on the fibrous tissue difference on thermal behavior and kinetics

The thermal properties of various corn stalk tissues (including stem, husk, ear, cob, and leaf), high-density polyethylene (HDPE), and their blends were investigated using thermogravimetric analysis under a nitrogen atmosphere. The results indicate that the thermal decomposition process of corn stalk tissue/HDPE mixtures is delayed with an increasing heating rate, regardless of the tissue type. Besides, the structural differences among various corn stalk tissues significantly influence their thermal behavior, product distribution, and co-pyrolysis kinetics with HDPE. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was conducted to analyze the pyrolytic products of the blends with different corn stalk tissues, revealing that corn cob/HDPE blends produce a higher yield of valuable chemicals, such as the furan derivates and aromatic hydrocarbons. Kinetic analysis was further performed using Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods to determine the activation energy for the reactions occurring during co-pyrolysis. The co-pyrolysis of corn cob/HDPE blend requires the least activation energy (149.3 kJ/mol) among five blends, which was ascribed to the high hemicellulose content in corn cob. Moreover, machine learning algorithms, including random forest (RF) and gradient boost regression tree (GBRT), were applied to predict mass loss in the corn fiber/HDPE blends, which showed RF possessed superior accuracy over GBRT. These findings suggest that isolating plant tissues during the feedstock pre-management could enhance the valorization performance of lignocellulose-waste plastic co-pyrolysis.

A novel homologous acid ferric chloride/5-sulfosalicylic acid coordinated catalytic pretreatment for high-efficiency selective separation of poplar hemicellulose

The selective and efficient separation of hemicellulose is a challenge for utilizing lignocellulosic biomass for high-value purposes. This study reports the development of a novel homogeneous acid-catalyzed pretreatment technique based the homologous action of both FeCl3 and 5-sulfosalicylic acid (5-SAA). The optimal separation conditions (5-SAA concentration of 7.0 %, reaction temperature of 130 °C, FeCl3 concentration of 0.15 mol·L−1, and reaction time of 60 min) enabled a high hemicellulose separation efficiency of 90.68 %. The hemicellulose-derived total sugar yield was as high as 83.05 % which was increased by 30 %. Moreover, the xylose yield was increased by 10 %, and the content of oligosaccharides was triple higher than that in the single component treatment, up to 19.64 %. The depolymerization and recondensation of lignin were prevented using the 5-SAA hydrophobic structure (benzene ring structure) and hydrophilic end (−HSO3 and −COOH). The proposed strategy is a promising approach that can enable an efficient and selective separation of hemicellulose and consequently improve the quality of biomass materials.

Effect of Brittleness in Rice Straw on Rumen Fermentation by In vitro Gas Production Technique

The objective of this study was to examine the impact of rice straw brittleness on its efficacy as roughage for ruminants, in comparison to a wild-type variety, utilizing an in vitro study approach. The experimental design was a complete randomized design (CRD). The experimental treatments included various breeds of rice straw (RS), such as the wild-type (WT, T1), the green brittle bred line 8 and line 13 with brittleness level-3 (GBL8-B3, T2 and GBL13-B3, T3), and the purple brittle bred line 8 with brittleness level-5 (PBL8-B5, T4). The findings revealed that the brittleness RS group had higher levels of crude protein and hemicellulose, and lower levels of cellulose compared to the wild-type group. Brittleness RS varieties showed a significantly greater gas production accumulation (p = 0.001) and IVDMD (p = 0.003) compared to the WT group. At 8 h post-incubation, the brittleness RS group showed significantly higher (p = 0.004) total of volatile fatty acids concentration compared to the WT group. After 1 h of post-incubation, GBL8-B3 exhibited the highest (p = 0.032) proportion of propionate and the lowest (0.009) C2:C3 ratio. Additionally, the brittleness RS did not have any effect on the population of ruminal microorganisms. Based on the brittleness of RS, it can be deduced that it has a greater potential as a roughage source when compared to the wild-type variety, consequently enhancing the quality of RS for roughage intake by ruminants. HIGHLIGHTS Brittleness RS exhibited elevated levels of CP, high hemicellulose content, and lower cellulose levels compared to the WT group. The brittleness RS group displayed a rapid degradation rate impacting the total VFAs concentration and C2:C3 ratio, with the GBL8-B3 group demonstrating superior utilization efficiency. The brittleness of RS is indicative of a higher potential as a roughage source when compared to the wild-type variety, thereby improving the quality of rice straw for roughage consumption by ruminants. GRAPHICAL ABSTRACT

Evaluating the role of feedstock composition and component interactions on biomass gasification

Biomass gasification offers a solution to waste concerns while generating clean energy. This study examines the gasification of pine sawdust (PS), used ground coffee (UGC), and wheat straw (WS) under identical conditions. The compositions of the biomass samples are determined, and the gasification of individual components (hemicellulose, cellulose, and lignin) are conducted to understand the process’ dependency on the biomass characteristics. The results suggest cellulose and cellulose-rich biomass (PS) produces more tar and less hydrogen than lignin and lignin-rich biomass (UGC and WS). High lignin and hemicellulose content leave more char. Gasification of PS, UGC, and WS yields 12.7, 15.7, and 17.2 vol% hydrogen, respectively. Additionally, cellulose, hemicellulose, and lignin gasification yield 10.5, 22.1, and 30.4 vol% hydrogen, respectively. Comparing experimental and theoretical values for the three biomass samples reveals significant differences due to component interactions. Thermogravimetry analysis (TGA) indicates significant degradation interactions between hemicellulose-lignin, cellulose-hemicellulose, and cellulose-lignin. It is concluded that high cellulose content biomass shows more predictable results, while high lignin and hemicellulose biomass increases secondary reactions or interactions, exacerbating predictability. These findings assist in estimating gasification performance for better biomass selection.

Xylitol production from passion fruit peel hydrolysate: Optimization of hydrolysis and fermentation processes

The passion fruit peel (PFP) has a high cellulose and hemicellulose content, which can be used to produce fermentable sugars. In this context, this study aims to optimize the release of xylose and the production of xylitol from PFP. The optimized conditions were 0.71 M dilute sulfuric acid and a 21.84-minute treatment, yielding 19.03 g/L of xylose (PFP-1). Different PFP hydrolysates were evaluated to improve xylitol production by the yeast Kluyveromyces marxianus ATCC 36907: PFP-2 (PFP1 treated with Ca(OH)2), PFP-3 (PFP-1 treated with Ca(OH)2 and activated carbon), PFP-4 (PFP-3 with biological elimination of glucose with S. cerevisiae, and concentrated at different xylose concentrations). The applied methods resulted in higher xylitol production (14.97 g/L), when PFP hydrolysate was detoxified with Ca(OH)2, treated with activated charcoal for 1 h, biotreated for glucose removal, and concentrated to 40 g/L of xylose.

Study on the hydrothermal gradient extraction of hemicellulose by a flow-through reactor

The hydrothermal gradient extraction process based on the hemicellulose constituent units is important for obtaining high quality hemicellulose products. The hydrothermal extraction of sawdust hemicellulose was performed under both non-isothermal and isothermal operations using a flow-through reactor for investigating the extraction patterns. The results show that there were significant differences in the major forms of hemicellulose units at different extraction stages. For glucose, xylose, and galactose units, the selectivity of oligomeric form decreased gradually with increasing temperature, whereas it decreased and then increased under thermostatic operation. The selectivity of the mannose oligomeric form decreased and then increased in both operation modes, reaching a trough at 170 °C (96.81 %) and 60 min (55.21 %), respectively. The molecular weight of extracted hemicelluloses were mainly distributed below 70,000 Da, and gradually decreased with temperature, but increased with time. The results contribute to the quantitative and qualitative understanding of the hemicellulose gradient extraction process.

Oil palm frond leaves (OPFLs), a high recalcitrant biomass as an alternative cellulose source for glucose conversion

Among the oil palm biomass, oil palm frond leaves (OPFLs) are under-valued since they can be classified as a high recalcitrance feedstock due to the high lignin and hemicellulose content. This work proposes a new way of using OPFLs as alternative cellulose sources for glucose conversion by an application of various pre-treatments at varying parameters. From green pre-treatment, steam explosion (SE) is much more effective in disrupting the OPFLs structure in contrast to hydrothermal (HT) pre-treatment, by a vast dissolution of hemicellulose and depolymerization of lignin. The pre-impregnation with H2SO4 prior to steam explosion was beneficial to enhance the hemicellulose removal up to 89.94 %. The 2D-HSQC NMR analysis divulged the reduction of ß-O-4 linkage and S/G value after the SE and HT pre-treatment, verifying the degradation of lignin-carbohydrate linkage in OPFLs. Meanwhile, the dilute NaOH pre-treatment enhanced the delignification by 87.14 %. SEM analysis revealed a well-disrupted structure of pre-treated OPFLs exposing a higher cellulosic fraction, whereas SEC analysis divulged a decreasing pattern of degree of polymerization of cellulose. The enzymatic analysis revealed that pre-treated OPFLs yielded higher glucose ranging from 29.81 % to 49.98 % w/w, which was ∼3-fold higher than raw OPFLs (14.31 % w/w). A maximum cellulose digestibility (100 %) was achieved by steam-exploded OPFLs after 72 h of enzymatic hydrolysis. This suggests the potency of various pre-treatments to enhance enzymatic saccharification of OPFLs producing a higher glucose yield.

The Impact of Biomass Composition Variability on the Char Features and Yields Resulted through Thermochemical Processes.

This paper explores the intricate relations between biomass polymeric composition, thermochemical conversion routes, char yields and features in order to advance the knowledge on biomass conversion processes and customize them to meet specific requirements. An exhaustive characterization has been performed for three types of biomasses: (i) spruce bark, a woody primary and secondary residue from forestry and wood processing; (ii) wheat straws-agricultural waste harvest from arable and permanent cropland; and (iii) vine shoots, a woody biomass resulting from vineyard waste. Chemical (proximate and ultimate analysis), biochemical, trace elements, and thermal analyses were performed. Also, Fourier transform infrared spectroscopy, Scanning Electron Microscopy, and thermogravimetric analysis were conducted to establish the compositional and structural characteristics of feedstock. The main polymeric components influence the amount and quality of char. The high hemicellulose content recommends wheat straws as a good candidate especially for hydrothermal carbonization. Cellulose is a primary contributor to char formation during pyrolysis, suggesting that vine shoots may yield higher-quality char compared to that converted from wheat straws. It was shown that the char yield can be predicted and is strongly dependent on the polymeric composition. While in the case of spruce bark and wheat straws, lignin has a major contribution in the char formation, cellulose and secondary lignin are main contributors for vine shoots char.

Conversion of WastePaper into Dissolving Pulp: A Path for Circular Bioeconomy

AbstractFollowing the circular bioeconomy concept, this work studies the potential of an industrial wastepaper residue as an alternative raw material for dissolving pulp‐grade production. Prehydrolysis‐kraft cooking (PHK), elemental chlorine‐free (ECF) bleaching, and acid‐washing treatments were applied to achieve that aim. Considering the high lignin and hemicellulose content of the raw material, it was submitted to PHK pulping to enhance its cellulose content by removing those components. This processing resulted in a remarkable increase of 84 % in pulp Fock reactivity (from 45.6 % to 84.1 %). The dissolution extension and time in solvent systems LiCl/DMAc and NMMO/H2O were discussed regarding the pulp physicochemical properties. The dissolving pulp produced under this work showed great potential as raw material for textile applications, particularly highlighting the innovative process developed to improve its solubility.

Experimental analysis of the effects of feedstock composition on the plastic and biomass Co-gasification process

Co-gasification is a feasible approach to manage fast-growing plastic and biomass waste issues. The current work examines air gasification of plastic waste blending with biomass. The influence of plastic-type and biomass characteristics on product distribution under the same operating condition was studied. Ethylene-vinyl acetate, high-density polyethylene, and polypropylene were the investigated plastics while the biomass materials considered were pine sawdust (PS), used ground coffee (UGC), and wheat straw (WS) are compared. Additionally, co-gasification and thermogravimetric analyses (TGA) of plastic and individual biomass components, namely, cellulose, hemicellulose, and lignin, were conducted to identify the nature of the synergy arising from plastic and biomass integration. Similarities in the chemical structure and composition of the investigated plastics resulted in the type of plastic marginally influencing product distribution. The gas composition included 4.6 vol% CH4, 37.5 % CO2, 5.3 % CnHm, 42 % CO, and 10.8 % H2, with yields of 5.9 wt% char, 39.5 wt% gas, and 54.8 wt% tar. Conversely, the type of biomass had a substantial effect on both gas composition and product yields. WS and UGC, characterized by higher hemicellulose and lignin content, generated more hydrogen with 14.4 and 13.3 vol%, respectively, and exhibited lower tar content (45.7 and 47.8 wt%) compared to PS, which has a higher cellulose content and yielded 54.8 wt% tar. During EVA/cellulose co-gasification, the predominant gases produced are CO and CO2, with H2 concentration of 7.2 vol%. In contrast, co-gasification of EVA/xylan and EVA/lignin yields 13.5 and 19.9 vol% hydrogen, respectively. Interactions and synergism between the plastic and biomass were found to be more intensified when the biomass contained greater proportions of cellulose and lignin. Co-gasification and TGA analyses indicated that plastic/cellulose and plastic/lignin interactions in the gas and solid phases (volatile-volatile and volatile-char interactions) and plastic/xylan interactions in the gas phase (volatile-volatile interactions) were significant. Modeling the predictability of the output data revealed that if interactions between the plastic and biomass components are accounted for, the co-gasification results are predictable with a credible accuracy for all biomass types. The predictability model offers a practical approach for selecting an appropriate co-gasification feedstock combination to give a targeted process performance.

Analysis of spatiotemporal changes mechanism of cell wall biopolymers and monosaccharide components in kiwifruit during Botryosphaeria dothidea infection

To further reveal the interaction mechanism between plants and pathogens, this study used confocal Raman microscopy spectroscopy (CRM) combined with chemometrics to visualize the biopolymers distribution of kiwifruit cell walls at different infection stages at the cellular micro level. Simultaneously, the changes in the content of various monosaccharides in fruit were studied at the molecular level using high-performance liquid chromatography (HPLC). There were significant differences in the composition of various nutrient components in the cell wall structure of kiwifruit at different infection times after infection by Botryosphaeria dothidea. PCA could cluster samples with infection time of 0–9 d into different infection stages, and SVM was used to predict the PCA classification results, the accuracy >96 %. Multivariate curve resolution-alternating least squares (MCR-ALS) helped to identify single substance spectra and concentration signals from mixed spectral signals. The pure substance chemical imaging maps of low methylated pectin (LMP), high methylated pectin (HMP), cellulose, hemicellulose, and lignin were obtained by analyzing the resolved concentration data. The imaging results showed that the lignin content in the kiwifruit cell wall increased significantly to resist pathogens infection after the infection of B. dothidea. With the development of infection, B. dothidea decomposed various substances in the host cell walls, allowing them to penetrate the interior of fruit cells. This caused significant changes in the form, structure, and distribution of various chemicals on the fruit cell walls in time and space. HPLC showed that glucose was the main carbon source and energy substance obtained by pathogens from kiwifruit during infection. The contents of galactose and arabinose, which maintained the structure and function of the fruit cell walls, decreased significantly and the cell wall structure was destroyed in the late stage of pathogens infection. This study provided a new perspective on the cellular structure changes caused by pathogenic infection of fruit and the defense response process of fruit and provided effective references for further research on the mechanisms of host-pathogen interactions in fruit infected by pathogens.

Comprehensive assessment of turfgrass wear tolerance: A study on mechanical and chemical traits

A key criterion in the selection process for turfgrass breeding is effective wear tolerance, indicating the plant's capacity to endure forces that may impact leaves, stems, crowns, and roots. In this study, the correlation between mechanical and chemical traits and the wear tolerance of 37 cultivars belonging to seven turfgrass species was examined. Mechanical properties and fiber characteristics of wide range of turfgrass cultivars were determined and compared for the first time. The evaluation of turf wear tolerance (described as turf cover index, TCI) was conducted through a three-year field trial using a Brinkman traffic simulator. Tensile tests were conducted to determine biomechanical parameters. According to the TCI, the most wear-resistant cultivars were those of Lolium perenne, Most of these cultivars demonstrated a TCI below 0.1. The cultivar 'Nira' was the most resistant, with a TCI of − 0.285. The least resilient cultivars belonged to Festuca ovina and Festuca rubra, all exhibiting TCI values above 0.6. Agrostis stolonifera and Agrostis capillaris were characterised by lower cellulose and acid detergent fiber content but high hemicellulose content. The opposite result was determined for Festuca rubra and Festuca ovina. The highest hemicellulose ratio was obtained for Poa pratensis. Lolium perenne was characterised by relatively high content of cellulose, lignin and hemicellulose. Cultivars of Festuca arundinace distinctly differed from other cultivars, demonstrating higher mechanical resistance with an average force-to-break of 3.73 N. Cultivars of Agrostis stolonifera and Agrostis capillaris reached force-to-break values up to 1.0 N. The relationships between TCI and fiber composition of turfgrass leaves were significant for crude fiber, NDF and hemicellulose content. Thus higher NDF and hemicellulose content resulted in higher force-to-break and work-to-break parameters.

A NAC transcription factor represses a module associated with xyloglucan content and regulates aluminum tolerance.

The transcriptional regulation of aluminum (Al) tolerance in plants is largely unknown, although Al toxicity restricts agricultural yields in acidic soils. Here, we identified a NAM, ATAF1/2, and cup-shaped cotyledon 2 (NAC) transcription factor that participates in Al tolerance in Arabidopsis (Arabidopsis thaliana). Al substantially induced the transcript and protein levels of ANAC070, and loss-of-function mutants showed remarkably increased Al sensitivity, implying a beneficial role of ANAC070 in plant tolerance to Al toxicity. Further investigation revealed that more Al accumulated in the roots of anac070 mutants, especially in root cell walls, accompanied by a higher hemicellulose and xyloglucan level, implying a possible interaction between ANAC070 and genes that encode proteins responsible for the modification of xyloglucan, including xyloglucan endo-transglycosylase/hydrolase (XTH) or ANAC017. Yeast 1-hybrid analysis revealed a potential interaction between ANAC070 and ANAC017, but not for other XTHs. Furthermore, dual-luciferase reporter assay, RT-qPCR, and GUS analysis revealed that ANAC070 could directly repress the transcript levels of ANAC017, and knockout of ANAC017 in the anac070 mutant partially restored its Al sensitivity phenotype, indicating that ANAC070 contributes to Al tolerance mechanisms other than suppression of ANAC017 expression. Further analysis revealed that the core transcription factor SENSITIVE TO PROTON RHIZOTOXICITY 1 (STOP1) and its target genes, which control Al tolerance in Arabidopsis, may also be involved in ANAC070-regulated Al tolerance. In summary, we identified a transcription factor, ANAC070, that represses the ANAC017-XTH31 module to regulate Al tolerance in Arabidopsis.

Higher efficiency of vanadate iron in heterogeneous Fenton-like systems to pretreat sugarcane bagasse and its enzymatic saccharification.

Pretreatment is crucial for effective enzymatic saccharification of lignocellulose such as sugarcane bagasse (SCB). In the present study, SCB was pretreated with five kinds of heterogeneous Fenton-like systems (HFSs), respectively, in which α-FeOOH, α-Fe2O3, Fe3O4, and FeS2 worked as four traditional heterogeneous Fenton-like catalysts (HFCs), while FeVO4 worked as a novel HFC. The enzymatic reducing sugar conversion rate was then compared among SCB after different heterogeneous Fenton-like pretreatments (HFPs), and the optimal HFS and pretreatment conditions were determined. The mechanism underlying the difference in saccharification efficiency was elucidated by analyzing the composition and morphology of SCB. Moreover, the ion dissolution characteristics, variation of pH and Eh values, H2O2 and hydroxyl radical (·OH) concentration of FeVO4 and α-Fe2O3 HFSs were compared. The results revealed that the sugar conversion rate of SCB pretreated with FeVO4 HFS reached up to 58.25%, which was obviously higher than that under other HFPs. In addition, the surface morphology and composition of the pretreated SCB with FeVO4 HFS were more conducive to enzymatic saccharification. Compared with α-Fe2O3, FeVO4 could utilize H2O2 more efficiently, since the dissolved Fe3+ and V5+ can both react with H2O2 to produce more ·OH, resulting in a higher hemicellulose and lignin removal rate and a higher enzymatic sugar conversion rate. It can be concluded that FeVO4 HFP is a promising approach for lignocellulose pretreatment.

Climate, litter quality and radiation duration jointly regulate the net effect of UV radiation on litter decomposition

Photodegradation via ultraviolet (UV) radiation is an important factor driving plant litter decomposition. Despite increasing attention to the role of UV photodegradation in litter decomposition, the specific impact of UV radiation on the plant litter decomposition stage within biogeochemical cycles remains unclear at regional and global scales. To clarify the variation rules of magnitude of UV effect on plant litter decomposition and their regulatory factors, we conducted a meta-analysis based on 54 published papers. Our results indicated that UV significantly promoted the mass loss of litter by facilitating decay of carbonaceous fractions and release of nitrogen and phosphorus. The promotion effect varied linearly or non-linearly with the time that litter exposed to UV, and with climatic factors. The UV effect on litter decomposition decreased first than increased on precipitation and temperature gradients, reaching its minimum in the area with a precipitation of 400–600 mm, and a temperature of 15–20 °C. This trend might be attributed to a potential equilibrium between the photofacilitation and photo-inhibition effects of UV under this condition. This variation in UV effect on precipitation gradient was in agreement with the fact that UV photodegradation effect was weakest in grassland ecosystems compared to that in forest and desert ecosystems. In addition, initial litter quality significantly influenced the magnitude of UV effect, but had no influence on the correlation between UV effect and climate gradient. Litter with lower initial nitrogen and lignin content shown a greater photodegradation effect, whereas those with higher hemicellulose and cellulose content had a greater photodegradation effect. Our study provides a comprehensive understanding of photodegradation effect on plant litter decomposition, indicates potentially substantial impacts of global enhancements of litter decomposition by UV, and highlights the necessity to quantify the contribution of photochemical minerallization pathway and microbial degradation pathway in litter decomposition.

Combination of microwave with acid deep eutectic solvent pretreatment for reed (Phragmites australis) fractionation

The cost-effective and low-carbon fractionation of lignocellulosic biomass will enhance the economic viability of bio-refining. To achieve efficient reed fractionation under favorable conditions, microwave-assisted choline chloride and p-toluene sulfonic acid (M-ChCl/p-TsOH) pretreatment was employed. The fractionation of reed components demonstrated higher effectiveness with M-ChCl/p-TsOH pretreatment compared to conventional DES pretreatment. Under M-ChCl/p-TsOH conditions, a high hemicellulose removal rate (∼90%) and delignification rate (∼65%) were achieved while achieving a saccharification rate of 88% during cellulase hydrolysis. Microwave assistance not only significantly reduced reaction time to less than 60 s but also enhanced the pretreatment efficacy. Furthermore, the obtained lignin products consisted of low-polymerization lignin (MW < 800 g/mol) and acid-soluble lignin, providing a solid foundation for subsequent high-value utilization of lignin. This study provides a promising strategy for the low carbon fractionation of reed using DES, aiming to simultaneously achieve efficient cellulose hydrolysis and obtain tractable lignin.

Solid Wood Modification toward Anisotropic Elastic and Insulative Foam-Like Materials.

The methods used to date to produce compressible wood foam by top-down approaches generally involve the removal of lignin and hemicelluloses. Herein, we introduce a route to convert solid wood into a super elastic and insulative foam-like material. The process uses sequential oxidation and reduction with partial removal of lignin but high hemicellulose retention (process yield of 72.8%), revealing fibril nanostructures from the wood's cell walls. The elasticity of the material is shown to result from a lamellar structure, which provides reversible shape recovery along the transverse direction at compression strains of up to 60% with no significant axial deformation. The compressibility is readily modulated by the oxidation degree, which changes the crystallinity and mobility of the solid phase around the lumina. The performance of the highly resilient foam-like material is also ascribed to the amorphization of cellulosic fibrils, confirmed by experimental and computational (molecular dynamics) methods that highlight the role of secondary interactions. The foam-like wood is optionally hydrophobized by chemical vapor deposition of short-chained organosilanes, which also provides flame retardancy. Overall, we introduce a foam-like material derived from wood based on multifunctional nanostructures (anisotropically compressible, thermally insulative, hydrophobic, and flame retardant) that are relevant to cushioning, protection, and packaging.

Production of activated carbon from agave residues and its synergistic application in a hybrid adsorption-AOPs system for effective removal of sulfamethazine from aqueous solutions

Tequila production in Mexico generates large quantities of agave bagasse (AB), a waste that could be used more efficiently. AB has a high cellulose, hemicellulose, and lignin content, which allows its use as a precursor for synthesizing carbonaceous materials. In the present work, the synthesis of activated carbon impregnated with Fe2+ (AG-Fe-II) and Fe3+ (AG-Fe-III) was carried out and evaluated in a hybrid adsorption-AOP (advanced oxidation process) methodology for sulfamethazine removal (SMT). The materials were characterized before and after the process to determine their morphological, textural, and physicochemical properties. Subsequently, the effect of the main operational variables (pH, initial SMT concentration, mass, and activator dosage) on the hybrid adsorption-degradation process was studied. The Fenton-like reaction was selected as the AOP for the degradation step, and potassium persulfate (K2S2O8) was used as an activating agent. The main iron crystallographic phases in AG-Fe-II were FeS, with a uniform distribution of iron particles over the material's surface. The main crystallographic phase for AG-Fe-III was Fe3O4. The hybrid process achieved 61% and 78% removal efficiency using AG-Fe-II and AG-Fe-III samples, respectively. The pH and initial SMT concentration were the most critical factors for removing SMT from an aqueous phase. Finally, the material was successfully tested in repeated adsorption-degradation cycles.

Catalytic Supercritical Water Gasification of Canola Straw with Promoted and Supported Nickel-Based Catalysts.

Lignocellulosic biomass such as canola straw is produced as low-value residue from the canola processing industry. Its high cellulose and hemicellulose content makes it a suitable candidate for the production of hydrogen via supercritical water gasification. However, supercritical water gasification of lignocellulosic biomass such as canola straw suffers from low hydrogen yield, hydrogen selectivity, and conversion efficiencies. Cost-effective and sustainable catalysts with high catalytic activity for supercritical water gasification are increasingly becoming a focal point of interest. In this research study, novel wet-impregnated nickel-based catalysts supported on carbon-negative hydrochar obtained from hydrothermal liquefaction (HTL-HC) and hydrothermal carbonization (HTC-HC) of canola straw, along with other nickel-supported catalysts such as Ni/Al2O3, Ni/ZrO2, Ni/CNT, and Ni/AC, were synthesized for gasification of canola straw on previously optimized reaction conditions of 500 °C, 60 min, 10 wt%, and 23-25 MPa. The order of hydrogen yield for the six supports was (10.5 mmol/g) Ni/ZrO2 > (9.9 mmol/g) Ni/Al2O3 > (9.1 mmol/g) Ni/HTL-HC > (8.8 mmol/g) Ni/HTC-HC > (7.7 mmol/g) Ni/AC > (6.8 mmol/g) Ni/CNT, compared to 8.1 mmol/g for the non-catalytic run. The most suitable Ni/ZrO2 catalyst was further modified using promotors such as K, Zn, and Ce, and the performance of the promoted Ni/ZrO2 catalysts was evaluated. Ni-Ce/ZrO2 showed the highest hydrogen yield of 12.9 mmol/g, followed by 12.0 mmol/g for Ni-Zn/ZrO2 and 11.6 mmol/g for Ni-K/ZrO2. The most suitable Ni-Ce/ZrO2 catalysts also demonstrated high stability over their repeated use. The superior performance of the Ni-Ce/ZrO2 was due to its high nickel dispersion, resilience to sintering, high thermal stability, and oxygen storage capabilities to minimize coke deposition.