Wood Cellulose Research Articles

Using δ15N and δ13C and nitrogen functionalities to support a fire origin for certain inertinite macerals in a No. 4 Seam Upper Witbank coal, South Africa

Fires are likely to have been central to the formation of certain inertinite macerals in South African coals. To investigate this hypothesis, a Permian, medium rank C bituminous Witbank coal (No. 4 Seam Upper) was density fractionated to yield an inertinite-rich and a vitrinite-rich sample, and assessed using stable nitrogen and carbon (δ15N and δ13C) isotopes in conjunction with nitrogen functionalities. The parent coal comprises of 41.6 vol% vitrinite and 48.5 vol% inertinite. The vitrinite-rich sample is dominated by collotelinite and collodetrinite (81 vol% vitrinite), and the inertinite-rich sample by fusinite, semifusinite, and inertodetrinite (63 vol% inertinite). The δ15N and δ13C values and nitrogen functionalities were used to constrain early coal formation pathways for the dominant macerals in the density fractionated samples. The vitrinite-rich sample has a lower δ13C relative to the inertinite-rich counterpart. However, the inertinite-rich sample has the lower δ15N value, along with a lower concentration of N-quaternary and higher N-pyrrolic compounds. Because these samples are of the same coal maturity, and the major macerals were derived from similar precursors, differences in δ15N and δ13C and nitrogen functionalities reflect differences in coal formation pathways. Degradation of 13C-rich cellulose in wood through either charring or bacterial activity leads to lower δ13C values. The lower 14N content for the vitrinite-rich sample along with higher N-quaternary and N-pyridinic suggests cellulose degradation driven by bacterial activity. In contrast, the higher 14N coupled with higher N-pyrrolic and N-oxide complexes for the inertinite-rich sample, suggests fusinite and semifusinite were formed through charring. Inertodetrinite is attributed to the disintegration of the charred matter.

Novel Biobased Textile Fiber from Colombian Agro-Industrial Waste Fiber.

Fique fibers, native to Colombia, are traditionally used for ropes and bags. In the extraction of long fibers for these purposes, the same amount of short fibers is generated; the short fibers are then discarded in the soil or in landfills. This agro-industrial waste is cellulose-rich and can be potentially developed into new biobased products. As an alternative use for these fibers, viscose regenerated fibers with potential applications in the textile industry were developed. Fique waste fibers were pulped (to produce fique cellulose pulp, FCP) using a 33 design of experiment (DOE) to adjust the variables of the whitening treatment, and DOE analysis showed that time and hydrogen peroxide concentration do not have a significant effect on non-cellulosic remotion, unlike temperature. The behavior of this pulp in the production of viscose was compared against that of commercially available wood cellulose pulp (WCP). FCP showed a suitable cellulose content with a high degree of polymerization, which makes it a viable pulp for producing discontinuous viscose rayon filaments. Both pulps showed the same performance in the production of the viscose dope and the same chemical, thermal, and mechanical behavior after being regenerated.

Wood pulp fiber modification by layer-by-layer (LBL) self-assembly of chitosan/carboxymethyl cellulose complex: Confocal microscopy characterization

Bleached cellulose wood pulp fibers from eucalyptus were modified by layer-by-layer (LbL) self-assembly of chitosan/carboxymethylcellulose (CH/CMC) complex. Pulp fibers modified with 10, 20 and 30 bilayers of CH/CMC were prepared and characterized by scanning electron microscopy (SEM) and by laser scanning confocal microscope (LSCM) using the two-photon absorption technique. CH/CMC complex was also deposited onto glass and regenerated cellulose (cellophane) films in order to evaluate the depositions process. CH/CMC films with up to 2750 nm thickness deposited on glass and cellophane were easily observed by SEM, however the films deposited onto a wood pulp fiber surface were visualized only using the LSCM technique since it is very difficult to observe the interface between CH/CMC and cellulose by SEM. Using confocal microscopy allows a precise characterization of the CH/CMC films, which were observed outside and inside the wood pulp fibers. This result also shows that during LbL processing, the polyelectrolyte solution penetrates very fast inside the hollow fiber leading to a complete surface modification of the fiber. Fibers can be considered as hollow tubes with an inner diameter of the order of 15–20 μm and external diameter of the order of 25 μm with a cellulose wall of 5 μm.

Knockdown of PCBER1, a gene of neolignan biosynthesis, resulted in increased poplar growth

Poplar trees displayed an increased plant height due to the transgenic knockdown of PCBER1, a gene of lignan biosynthesis. The wood composition was slightly altered in both overexpression and knockdown lines. The gene PHENYLCOUMARAN BENZYLIC ETHER REDUCTASE1 (PCBER1) is well known as an important gene in the synthesis of lignans, a group of diverse phenylpropanoid derivatives. They are widely distributed in the plant kingdom and may have a role in both plant defense and growth regulation. To analyze its role in biomass formation and wood composition in poplar, both overexpression and knockdown approaches have been performed. Transgenic lines were analyzed on genetic and phenotypic levels, and partly in regard to their biomass composition. While the PCBER1 overexpression approach remained unremarkable concerning the plant height, biomass composition of obtained transgenic lines was modified. They had a significantly increased amount of ethanol extractives. The PCBER1 knockdown resulted in significantly deviating plants; after 17months of greenhouse cultivation, transgenic plants were up to 38% higher compared to non-transgenic wild type. Most examined transgenic lines did not reveal a significantly enhanced stem diameter after three vegetation periods in the greenhouse. Significant changes were not obtained with regard to the three major wood components, lignin, cellulose and hemicelluloses. As a slight but not significant reduction in ethanol extractives was detected, the hypothesis arises that the lignan content could be influenced. Lignans become important in the pharmaceutical industry and clinical studies concerning cancer and other diseases, thus further investigations on lignan formation in poplar and its connection to biomass formation seem promising.

A fast method to prepare mechanically strong and water resistant lignocellulosic nanopapers

This study covers a green method to prepare hybrid lignocellulosic nanopapers by combining wood nanofibres (WNFs) and cellulose nanofibres (CNFs). The WNFs and CNFs behave synergistically to compensate for the drawbacks of each other resulting in enhanced hybrid nanopapers. The draining time of hybrid nanopapers was improved by up to 75% over CNF nanopaper, and the mechanical properties, modulus, strength and elongation, were respectively improved up to 35%, 90% and 180% over WNF nanopaper. Additionally, the water resistance of hybrid nanopapers was considerably improved with a water contact angle of 95°; the neat CNF nanopaper had a contact angle of 52°. The morphology of nanopapers, studied by electron microscopy, indicated that lignin acts as a matrix, which binds the nanofibres together and makes them impervious to external environmental factors, such as high humidity. The reported hybrid nanopapers are 100% bio-based, prepared by a simple and environmentally friendly processing route. Reported hybrid nanopapers can be used in novel applications such as gas barrier membranes and printable electronics.

Integrated Process for the Enzymatic Production of Fatty Acid Sugar Esters Completely Based on Lignocellulosic Substrates.

Lignocellulose can be converted sustainably to fuels, power and value-added chemicals like fatty acid esters. This study presents a concept for the first eco-friendly enzymatic synthesis of economically important fatty acid sugar esters based on lignocellulosic biomass. To achieve this, beech wood cellulose fiber hydrolysate was applied in three manners: as sugar component, as part of the deep eutectic solvent (DES) reaction system and as carbon source for the microbial production of the fatty acid component. These fatty acids were gained from single cell oil produced by the oleaginous yeast Cryptococcus curvatus cultivated with cellulose fiber hydrolysate as carbon source. Afterwards, an immobilized Candida antarctica lipase B was used as the biocatalyst in DES to esterify sugars with fatty acids. Properties of the DES were determined and synthesized sugar mono- and di-esters were identified and characterized using TLC, MS, and NMR. Using this approach, sugar esters were successfully synthesized which are 100% based on lignocellulosic biomass.

Physicochemical Aspects of Cellulose Processing Using Ionic Solvents. Review

Physicochemical aspects of modern technology for dissolution and spinning of wood cellulose solutions are discussed. The effects of the chemical structure of ionic solvents on the solubility of cellulose in them are analyzed.

Microwave-assisted glucose production from bode (Styrax tonkinensis) woody biomass for bioethanol production

Microwave (MW)-assisted acid hydrolysis of lignocellulosic material derived from bode (Styrax tonkinensis) wood to glucose was performed to find effective uses for discarded chopsticks. The maximum amount of glucose produced by MW-assisted acid hydrolysis (from 1 g of untreated bode wood cellulose) was 0.48 g, and was obtained by heating at 200 °C for 1 min using 1.0% (w/w) sulfuric acid as catalyst. However, the maximum total glucose yield from both MW-assisted acid hydrolysis (0.16 g) and enzymatic hydrolysis of the treated residue (0.52 g) was 0.68 g, which was obtained at a microwave heating temperature of 180 °C for 5 min using 1.0% (w/w) sulfuric acid as catalyst. In conclusion, the results showed that microwave-assisted treatment at 200 °C using 1.0% (w/w) sulfuric acid as catalyst facilitated MW-assisted acid hydrolysis of bode wood cellulose and treatment at 180 °C served as pretreatment for enzymatic hydrolysis of the treated residue.

Bacterial cellulose for increasing barrier properties of paper products

Bacterial cellulose was combined with wood cellulose papers in order to obtain biomaterials with increased barrier properties. For this purpose, different parameters were assessed: two producing bacterial strains (Komagataeibacter xylinus and Gluconacetobacter sucrofermentans), two paper supports to hold bacterial cellulose (filter paper and eucalyptus paper), two kinds of combined biomaterials (composite and bilayer) and two drying temperatures (90 °C and room temperature). Papers with increased barrier properties (100° of water contact angle, 1220 s of water drop test and air permeability < 1 µm (Pa s)−1) were obtained by the addition of bacterial cellulose to each paper support. However, due to the lower initial barrier properties of filter paper, higher improvements were produced with this paper. In addition, bacterial cellulose provided smoother surfaces with higher gloss without a detrimental effect on physical properties. Higher resistance to water absorption was obtained with K. xylinus possibly explained by its longer size fibers than G. sucrofermentans, as analysed by SEM. Smoothness and gloss were specially increased in the bilayer biomaterial although resistance to air and water were further improved in the composite. In this biomaterial drying at high temperature had a detrimental effect. SEM analysis of the products obtained showed the intimate contact among fibers of bacterial cellulose and wood paper. Results obtained show the contribution of bacterial cellulose to improve the properties of paper and its potential for the design of new added value paper products from biomass.

A new analytical approach to characterize the effect of γ-ray sterilization on wood

Irradiation with γ rays is widely used in the sterilization of a large variety of products and materials in the field of medical supplies, pharmaceuticals, cosmetics, food industry and cultural heritage. It is also applied on wood materials, with the purpose of improving their shelf-life, by lowering the microbial charge and hence the microbial-related deterioration rate. A fundamental issue when applying γ rays is the preservation of the chemico-physical as well as of the structural and mechanical properties of the materials irradiated, since a significant change of properties may jeopardize the use of the materials for the purpose intended. To this end, in this paper, we analyzed the chemico-physical properties of four different types of wood used for the construction of musical instruments namely fir, maple, poplar and durmast oak under increasing doses of γ rays. In detail, the effect of incremental radiation doses was evaluated by comparing the results obtained by acoustic tests with those providing information at molecular level, i.e., cyclic voltammetry, linear square voltammetry and infrared spectroscopy. Moreover, in this work, the glucose released as a result of the degradation of wood cellulose and hemicellulose, has been analyzed for the first time, with an innovative tool, based on the use of a Gellan gel. The integrated approach presented here, based on both traditional and innovative techniques has proven to be highly efficient in providing a complete picture of wood behavior following γ-ray irradiation, at both the macroscopic and the molecular level.

Preparation and Performance Analysis of Lignocellulose Water Retention Agent and Combination with Coal Gangue Ceramsite

Environmental friendly water retention agent has been widely used in agriculture, since its ability to absorb water, hold in water, resist salt. In this study, the water rentention agent was polymerized with using wood cellulose as raw material, acrylamide as monomer, N, N - methylene double acrylamide as crosslinking agent, ammonium persulfate as the initiator. The optimized technological conditions was obtained by the orthogonal experiments: the quality ratio of cellulose and acrylamide was in 1:6, ammonium persulfate was 1.5 wt%(of the total amount of cellulose and monomer), N, N - methylene double acrylamide 0.25 wt%(of the total amount of cellulose and monomer). The maximum water absorbency of water retention agent was 330.07g/g in distilled water and 117.48g/g in 0.9 wt% KCl solution. On the basis of this, using water retention agent as the coating for coal gangue ceramsite, and the maximum water absorbency of water retention agent was 332.15g/g in distilled water and 118.91g/g in 0.9wt% KCl solution. The results show that adopting above process not only can obtain good water retention agent, but also can enhance the water retention and salt resistance by using with ceramsite.

The effect of chemical composition on the charring of wood across scales

Structural softwood (timber) recently gained attention by architects and engineers as a construction material for high-rise buildings. Regulations restrict the height of these buildings due to safety concerns as their fire behaviour is poorly understood. The fire behaviour and loss of loadbearing capacity of timber is controlled by charring, whose chemical kinetics has rarely been studied. Current models of charring assume, without proof, the same reaction scheme and kinetic parameters apply to all wood species, which potentially introduces a large uncertainty. Here, the hypothesis is tested that the kinetics of different wood species insignificantly affects their charring behaviour. The kinetics is modelled by a microscale kinetic model—including pyrolysis and char oxidation reactions—which assumes that the three main components (cellulose, hemicellulose, and lignin) of wood degrade independently. Variation in the kinetics between different wood species is captured by their different chemical compositions within a wood group (softwood or hardwood). Hardwood is included for comparison. A database of over 600 compositions was compiled from literature, and studied across scales using a microscale (mg-samples) and mesoscale (kg-samples) model. All reactions, kinetic parameters, and physical properties were selected from literature. Both models were validated using blind predictions of high-fidelity experiments from literature. Variation in kinetics were found to have a small effect on the predicted mass loss rate at both scales (±1 g/m2-s) and a negligible effect on the predicted temperatures (±16 K) across different depths, heat fluxes, and oxygen concentrations at the mesoscale. These results prove, for the first time, that the variation in kinetics is negligible for predicting charring across scales. A kinetic model of charring derived for one wood species should be valid for all wood species within softwood or hardwood. Modellers should, therefore, focus on the difference in the physical properties instead of the kinetics between wood species.

Building Energy Opportunity with a Supply Chain Based on the Local Fuel-Producing Capacity

Studying and modeling plants for producing electric power obtained from vegetal wood cellulose biomass can become an opportunity for building a supply chain based on the local fuel-producing capacity. Focusing on energy-producing technologies, such as pyrolysis or gasification, the present work assessed the amount of vegetal biomass that may be used as fuel, both in terms of actual availability and supply price, in the Province of Rieti (Italy). The aim is to draw up a supply plan that has an intrinsic relationship with the local area. The results confirmed a production of 24 MW of project thermal power and 4 MW of project electric power. The ensuing plant was then studied following current norms about renewable energy, environmental consistency, and atmospheric emissions. An economic analysis of the cost investment was also carried out, where the total return is approximately of 19%. The results exposed that plant costs are acceptable only if short-supply chain fuel is purchased. The costs of generating energy from agroforestry biomass are certainly higher; however, the plant represents a significant territorial opportunity, especially for the economic sectors of agriculture and forestry. The employment effect plays a central role in the concession process, which is relevant for the interaction among renewable energy production and agriculture. The environmental impact of a biomass plant from agroforestry residues can be measured exclusively on atmospheric emissions: the plant must be placed in industrial areas without any landscape or naturalistic value.

Shape fixation of compressed wood by steaming: a mechanism of shape fixation by rearrangement of crystalline cellulose

Japanese cedar wood specimens were compressed radially using saturated water vapor at 160 °C. Their shape recovery in hot water, cellulose crystallinity, and dynamic viscoelastic properties were measured. The compressed shape of the wood was fixed completely with 120 min of steam compression. In addition, the tensile strain of the elongated steam-compressed wood specimens was recovered almost completely upon immersion in hot water. The crystallinity and crystal width of cellulose in the compressed wood increased with increasing steaming duration, corresponding to the fixation of the compressed shape and the recovery of tensile strain. These results suggested that the recrystallization or co-crystallization of cellulose, i.e., the reformation of elastic members in the wood cell walls, caused shape fixation by steam compression. When a wood specimen was compressed at 25 °C, its dynamic Young’s modulus in the radial (R) direction (ER) decreased, while its mechanical loss tangent (tan δR) increased remarkably. However, upon subsequent steaming, the reduced ER began increasing and the enhanced tan δR began decreasing. These changes were explained by a hypothetical slip–cure model in which microfractures and slippage between or within microfibrils were cured by the rearrangement of cellulose under steaming.

Assessment of the Fluctuations in the Microstructural Parameters of Cellulose in Wood in an Inhomogeneous Temperature Field

The possibility of assessing the average crystallite size of cellulose in wood by formalised modelling from the magnitude of the potential difference arising in the wood specimen owing to polarisation in a non-homogeneous temperature field is considered.

Characterization of Polypropylene Composite Reinforced with Wood Flour or Cellulose Fiber

The use of lignocellulosic materials as reinforced polymer composite has been in great demand during the last decade due to some of its advantages. The lignocellulosic material may be in the form of wood flour or cellulose fiber, both of which have different properties and structures due to effects of the resulting composite product. This study aims was to compare lignocellulosic materials as reinforcing agent in polypropylene composite, i.e in the form of wood flour or cellulose fibers. The characterization conducted were the physical and mechanical properties of the composite. The characteristics of lignocellulose materials were investigated using FTIR and XRD analysis. Cellulose fibers were obtained by pulping with an alkaline solution, followed by bleaching treatment. The results showed that the chemical treatments could increased the crystallinity of the fibers, therefore resulted in an increase of physical and mechanical properties of polypropylene composites.

Rapid uptake of pharmaceutical salbutamol from aqueous solutions with anionic cellulose nanofibrils: The importance of pH and colloidal stability in the interaction with ionizable pollutants

Micropollutants escaping conventional wastewater treatment processes pose a threat to biota and the environment. Amongst micropollutants, small and ionizable organic compounds are particularly challenging, since their removal depends significantly on prevailing conditions. In this study, anionic cellulose nanofibrils (CNFs) were shown to perform as promising adsorbents for an ionizable pharmaceutical, salbutamol. The adsorbents were produced from wood cellulose through succinylation pretreatment in urea-LiCl deep eutectic solvent (DES), followed by a nanofibrillation procedure. The impact of pH, contact time, salbutamol concentration, and adsorbent dose on salbutamol uptake were investigated in batch adsorption studies. Based on the results, the chemical modification of cellulose significantly enhanced the adsorption of salbutamol. The adsorption efficiency was mainly dependent on the charge and colloidal stability of the anionic nanofibril suspension rather than the charge of salbutamol, because the adsorption was considerably improved at pH > 7 due to the deprotonation of the cellulose carboxyl groups. The experimental maximum adsorption capacity was 196 mg/g. This study highlights the potential of cellulose nanomaterial adsorbents and the importance of controlling the charge of the adsorbent material when developing solutions for ionizable micropollutant removal.

Controlled pinewood fractionation with supercritical ethanol: A prerequisite toward pinewood conversion into chemicals and biofuels

Abstract The objective of this work was to investigate the ability of supercritical (SC) ethanol conditions to attack preferentially the lignin fraction against the carbohydrate fraction and their effects on the product distribution among gases, light products, bio-oils, and chars. In this study, the conversion of each pinewood component was determined by the analysis of solid residues to quantify cellulose, hemicellulose, lignin, and char contents. It is shown that, by tuning the temperature, hemicellulose and lignin are already transformed in subcritical ethanol conditions, lignin being more reactive than hemicellulose. In contrast, native wood cellulose is recalcitrant to liquefaction in SC ethanol near the critical point (Tc = 241 °C and Pc = 61 bar), but 20% of native wood cellulose is converted in SC ethanol at 280 °C. Besides, the severity of the conditions, in terms of temperature and treatment time, does not significantly influence the yields of gases, light products, and bio-oils but strongly enhances char formation. Interestingly, the increase in SC ethanol density does not change the conversion of biomass components but has a marked effect on bio-oil yield and prevents char formation. The optimum fractionation conditions to convert the lignin component, while keeping unattacked the cellulose fraction with a minimum formation of char, are dense SC ethanol, at 250 °C for 1 h, in batch conditions. However, although lignin is more reactive than hemicellulose under these conditions, these fractions are converted, in a parallel way, to around 50% and 60%, respectively.

Dependence of the Physicochemical and Catalytic Properties of Ce0.5Zr0.5O2 Oxide on the Means of Synthesis

The effect the means of synthesis have on the texture, phase composition, redox properties, and catalytic activity of binary oxide systems with the composition Ce0.5Zr0.5O2 are studied. The obtained samples are characterized via BET, SEM, DTA, XRD, and Raman spectroscopy. A comparative analysis is performed of the physicochemical properties of biomorphic systems Ce0.5Zr0.5O2 obtained using wood sawdust and cellulose as templates and the properties of binary oxides of the same composition obtained by template-free means. The catalytic properties of the obtained oxide systems Ce0.5Zr0.5O2 are studied in the reaction of carbon black oxidation. It is shown that the texture of the oxide depends on the means of synthesis. When biotemplates are used, fragile porous systems form from thin binary oxide plates containing micro-, meso-, and macropores. Oxide obtained via coprecipitation consists of dense agglomerates with pores around 30 A in size. In supercritical water, nanoparticles of metal oxide form that are loosely agglomerated. The intermediate spaces between them act as pores more than 100 A in size. A system of single-phase pseudocubic modification is obtained using a cellulose template. The crystal lattices of all the obtained systems contain a great many defects. It is shown that the system prepared via synthesis in supercritical water has the best oxygen-exchange properties. A comparative analysis is performed of the effect the physicochemical properties of the samples have on their activity in the catalytic oxidation of carbon black.

Poly(ε-caprolactone) Biocomposites Based on Acetylated Cellulose Fibers and Wet Compounding for Improved Mechanical Performance

Poly(e-caprolactone) (PCL) is a ductile thermoplastic, which is biodegradable in the marine environment. Limitations include low strength, petroleum-based origin, and comparably high cost. Cellulose fiber reinforcement is therefore of interest although uniform fiber dispersion is a challenge. In this study, a one-step wet compounding is proposed to validate a sustainable and feasible method to improve the dispersion of the cellulose fibers in hydrophobic polymer matrix as PCL, which showed to be insensitive to the presence of the water during the processing. A comparison between unmodified and acetylated cellulosic wood fibers is made to further assess the net effect of the wet feeding and chemical modification on the biocomposites properties, and the influence of acetylation on fiber structure is reported (ATR-FTIR, XRD). Effects of processing on nanofibrillation, shortening, and dispersion of the cellulose fibers are assessed as well as on PCL molar mass. Mechanical testing, dynamic mechanical thermal a...