Residual Lignin Content Research Articles

RESEARCH THE CELLULOSE PRODUCTION PROCESS FROM AGRICULTURAL WASTE

The problem of raw material supply of cellulose and paper production exists because of the shortage of wood resources. Nowadays the use of waste processing agricultural and technical plants is relevant for pulping. Corn, the production of whichUkraineis the fifth largest in the world, is one of the most common agricultural plants. Corn stalks are valuable cellulosic raw materials that can be used for the fibrous semi-finished products production for various purposes.The purpose of the research is to study the quantitative and qualitative characteristics of the pulping process from corn stalks in the per-acetic acid solution with various concentrations. The dry ground corn stalks without leaves used for research. This raw material contains 41.6 % cellulose, 17.95 % lignin, 12.1 % pentosans, 3.52 % resins, fats and waxes, 23.7 % substances that extracted with a 1 % alkali solution, 11.8 % substances that extracted with water and 7.9 % minerals. Pulping was carried out in laboratory conditions during 2, 3 and 4 hours by per-acetic acid solution with concentration 5.6; 7.7 and 9.8 % at a temperature 90 ºC and a water ratio of 7 : 1. The fibrous semi-finished products were obtained with a yield of 65.5‑22.1 % by weight of absolutely dry raw materials, a residual lignin content of 17.7‑3.2 %, and an ash content of 5.3‑3 %.Adequate second-degree regression dependencies for qualitative indicators of cellulose – yield, residual lignin content, and ash content from pulping conditions – are built based on the full factorial experimental design. The tasks of multi-criteria optimization are solved using Harrington’s desirability function in deterministic conditions and based on the Bellman-Zade optimality principle under partial uncertainty. Under determinism, the optimal pulping conditions are the concentration of per-acetic acid in the solution – 9.2 %, the duration of cooking – 2 hours and 20 minutes. Under partial uncertainty, the optimal conditions for pulping are the concentration of per-acetic acid in the solution – 9.1 % and the duration of cooking – 2 hours.

REGULARITIES OF THE PROCESS OF PINE WOOD PEROXIDE DELIGNIFICATION IN THE PRESENCE OF SULFURIC ACID CATALYST

The known methods to obtain microcrystalline cellulose (MCC) from wood raw material is multi-stage and it is based on the integration of environmentally hazardous processes of pulping, bleaching and acid hydrolysis of cellulose amorphous part. The paper describes a one-stage catalytic method to obtain microcrystalline cellulose from pine wood based on peroxide delignification in acetic acid-water in the presence of a catalyst H2SO4. The optimal parameters of the process of pine wood peroxide delignification in the presence of 2% H2SO4 catalyst were determined by experimental and numerical methods: temperature – 100 °C, concentration H2O2 – 5 wt.%, CH3COOH – 25 wt.%, LWR 15, duration – 4 h. They provide a high yield of cellulose (45.2 wt.%) with a low content of residual lignin (1.0 wt%).The kinetic study of pine wood peroxide delignification at the temperature range 70-100 ºC was accomplished. The delignification process is described satisfactory by the first order equation in all temperature range. The rate constants vary between 0.08·10-4 and 2.15·10-4 s-1 and the activation energy is 90 kJmol-1. It was established by FTIR and XRD methods, that the cellulose, obtained from pine wood has the composition and structure similar to the commercial microcrystalline cellulose.

Structural Analysis on the Effect of Base-Catalysed Delignification Process Parameters on Palm Oil Empty Fruit Bunches Fibres using Glycome Profiling

Malaysian Oil Palm Empty Fruit Bunches (EFB) fibre was used as a model substrate and was subjected to base-catalysed delignification technique as a function of different temperature, time and base concentration. The resultant substrates were analysed using glycome profiling technique to ascertain the degree of delignification effectiveness and position of the residual lignin in the structure of the pre-treated biomass. The study indicated that the base-catalysed delignification technique removes all the outer lignin structure of the fibre due to the accessibility of the base to the surface of the biomass. Base wash concentration using sodium hydroxide (NaOH) and temperature are the two main factors that determine the effectiveness of lignin removal and increment of surface area accessibility (SAA). The pre-treated biomass that contains the lowest amount of residual lignin content of 6.19 wt.% which corresponds to 74.47% lignin removal shows complete removal of the outer layer of lignin structure but leaves the inner lignin structure intact. This study suggests that the complex interaction between different cell wall constituents plays a much bigger role in order to achieve efficient delignification.

Oxycellulose from Flax Fibers

Objective. Development of technologies for obtaining products from natural sources of raw materials, which after the end of its life cycle is subject to biodegradation, as an alternative to products from exhaustive sources of raw materials – oil, coal, gas.Objective. The aim of the paper is production of pulp from flax fibers by an ecologically safe method of delignification using peracetic acid solution and determining the influence of the main technological parameters of the cellulose oxidation process under the action of the TEMPO oxidant (2,2,6,6-tetramethyl-piperidine-1-oxyl) on the quality of oxycellulose.Methods. In the first stage of flax fiber processing, extraction was carried out with a solution of sodium hydroxide at a concentration of 7%, a liquid-to-solid ratio of 10: 1, lasting from 1 to 4 hours at a temperature of 95 ± 3 °C. In the second stage, pulping with a solution of peracetic acid at a temperature of 95 ± 3 °C, for 4 hours was carried out. The process of cellulose oxidation from flax fibers was carried out with a solution of TEMPO at a consumption of 1.5; 3.0; 5,0 and 10,0% by weight of absolutely dry raw materials at a temperature of 20, 40 and 60 °С and duration from 2 to 6 hours.Results. The chemical composition of flax fibers is given. The organosolvent pulp from flax fibers with a residual lignin content of 0.34% and an ash content of 0.03% was obtained, which was used for the TEMPO oxidation process. It is shown that an increase in the consumption of TEMPO oxidizer, duration and temperature of the oxidation process contribute to an increase in the content of carboxyl groups in the obtained oxycellulose samples from flax organosolvent pulp. It was established that by carrying out the process of oxidation of linseed cellulose at a TEMPO consumption of 5% of the mass of absolutely dry raw material, at a temperature of 60 °C and a duration of 6 hours, oxycellulose from a carboxyl group content of up to 5.3% was obtained.Conclusions. Obtained oxycellulose can be used in surgical practice as one of the components of non-toxic radioprotective, hemostatic, antimicrobial and wound healing materials.

Impact of the chemical composition of cellulosic materials on the nanofibrillation process and nanopaper properties

This paper investigated the impact of the amounts of lignin and hemicelluloses on cellulose nanofibers (CNFs). Birch and spruce wood were used to prepare holocellulose and cellulose samples by classical methods. To better assess the effect of the chemical composition on the CNF performance and simplify the process for CNF preparation, no surface derivatization method was applied for CNF preparation. Increased amounts of hemicelluloses, especially mannans, improved the defibration process, the stability of the CNFs and the mechanical properties, whereas the residual lignin content had no significant effect on these factors. On the other hand, high lignin content turned spruce nanopapers yellowish and, together with hemicelluloses, reduced the strain-at-break values. Finally, when no surface derivatization was applied to holocellulose and cellulose samples before defibration, the controlled preservation of residual lignin and hemicelluloses on the CNFs indicate to be crucial for the process. This simplified method of CNF preparation presents great potential for forest-based industries as a way to use forestry waste (e.g., branches, stumps and sawdust) to produce CNFs and, consequently, diversify the product range and reach new markets.

Microcrystalline Cellulose Based on Cellulose Containing Raw Material Modified by Steam Explosion Treatment

Today’s methods for producing powdered celluloses, in particular microcrystalline cellulose (MCC), from various plant raw materials, while applying new highly efficient methods for the isolation of cellulose are of a great interest. One of these methods is the production of MCC from lignocellulosic material activated by steam explosion treatment. The material obtained by this method from wood has a high reactivity, low content of residual lignin, a high specific surface, which allows to subject it successfully and efficiently to accelerated delignification or hydrolytic breakdown (degradation). This ability of the lignocellulosic material, activated by steam explosion, is the basis of this study, which provides the results of an experimental evaluation of the component and dispersion analysis of MCC, obtained from this material.

Optimizing Single-Stage Processes of Microcrystalline Cellulose Production via the Peroxide Delignification of Wood in the Presence of a Titania Catalyst

The conventional way of producing microcrystalline cellulose (MCC) from wood raw materials is multistage; it is based on integrating the environmentally hazardous processes of pulping and bleaching of cellulose and the acid hydrolysis of the amorphous phase of cellulose. This work describes an improved single-stage catalytic method for the production of MCC from softwood and hardwood that is based on the peroxide delignification of wood in an acetic acid–water medium under mild conditions (100°C, atmospheric pressure) in the presence of an environmentally safe TiO2 solid catalyst. The processes of MCC production via the peroxide catalytic delignification of various wood species are optimized experimentally and mathematically. The following optimum modes for the production of MCC with a yield of 36.3–42.0 wt % of absolutely dry wood, a residual lignin content of ≤1.0 wt %, and a hemicellulose content of ≤ 6.0 wt % are determined: For aspen: 5 wt % H2O2, 25 wt % CH3COOH, and a liquid/wood ratio of 10. For birch: 5 wt % H2O2, 25 wt % CH3COOH, and a liquid/wood ratio of 15. For silver fir: 6 wt % H2O2, 30 wt % CH3COOH, and a liquid/wood ratio of 15. For larch: 6 wt % H2O2, 30 wt % CH3COOH, and a liquid/wood ratio of 15.

Biodelignification of some agro-residues by Stenotrophomonas sp. CFB-09 and enhanced production of ligninolytic enzymes

Abstract Biological delignification is an environmental friendly pretreatment method for enhanced enzymatic hydrolysis of lignocellulosic biomass and fermentation processes. In an attempt to optimize delignification process which is crucial for effective biofuel production from agro-residues, this study investigated biodelignification of some agro-residues (coconut shell {CS}, coconut husk {CH}, palm kernel shell {PKS}, oil palm empty fruit bunch {OPEFB} and sawdust {SD}) by Stenotrophomonas sp. CFB-09 under submerged fermentation conditions. Initial lignin and residual lignin contents of each agro-residue were determined at the beginning and end of 216 h biodelignification period. Production of ligninolytic enzymes was monitored at 12 h intervals. Effects of nitrogen sources, temperature and pH on production of ligninolytic enzymes were determined over the biodegradation period. Remarkably, biodelignification of the agro-residues was in the range of 41–55%. Laccase had highest yield (31 U/mg) on CH, PKS and OPEFB. Lignin peroxidase production (381 U/mg) was maximum on OPEFB, and manganese peroxidase had highest yield (53 U/mg) on PKS. Surprisingly, there was appreciable production of ligninolytic enzymes at higher temperatures of biodegradation with 40–55% yield at 80 °C. Maximum enzyme production was achieved at 40 °C, pH 8.0 with ammonium nitrate as nitrogen source. Results provide deeper insights into biodelignification of agro-residues and demonstrate potential of Stenotrophomonas sp. CFB-09 for use in biodegradation of agro-residues, especially in pretreatment of lignocellulosic biomasses for production of biofuel and other value-added products.

Optimization of One-Stage Processes of Microcrystalline Cellulose Obtaining by Peroxide Delignification of Wood in the Presence of TiO2 Catalyst

The traditional method for obtaining microcrystalline cellulose (MCC) from wood raw material is multi-stage and it is based on the integration of environmentally hazardous processes of pulping and bleaching of cellulose and acid hydrolysis of amorphous part of cellulose. The paper describes an improved one-stage catalytic method of microcrystalline cellulose obtaining from softwood and hardwood based on peroxide delignification of wood in acetic acid-water medium under the mild conditions (100 °C, atmospheric pressure) in the presence of an environmentally safe solid catalyst TiO 2 . Experimental and mathematical optimization of the processes of MCC preparation by peroxide catalytic delignification of various types of wood was carried out. The following optimal modes of obtaining MCC with the yield 36.3–42.0 wt.% of abs. dry wood and residual lignin content ≤1.0 mas.%, hemicellulose ≤6.0 mas.% was established: for aspen – 5 wt.% H 2 O 2 , 25 wt.% CH 3 COOH, hydromodule = 10; for birch – 5 wt.% H 2 O 2 , 25 wt.% CH 3 COOH, hydromodule = 15; for abies – 6 wt.% H 2 O 2 , 30 wt.% CH 3 COOH, hydromodule = 15; for larch – 6 wt.% H 2 O 2 , 30 wt.% CH 3 COOH, hydromodule = 15.

Trichoderma Reesei single cell protein production from rice straw pulp in solid state fermentation

The dependency on fish meal as a major protein source for animal feed can lead toit priceinstability in line with the increasing in meat production and consumption in Indonesia. In order todeal with this problem, an effort to produce an alternative protein sources production is needed. This scenario is possible due to the abundantavailability of agricultural residues such as rice straw whichcould be utilized as substrate for production of single cell proteins as an alternative proteinsource. This work investigated the potential utilization of rice straw pulp and urea mixture as substrate for the production of local Trichoderma reesei single cell protein in solid state fermentation system. Some parameters have been analyzed to evaluate the effect of ratio of rice straw pulp to urea on mixed single cell protein biomass (mixed SCP biomass) composition, such as total crude protein (analyzed by kjedhal method) and lignin content (TAPPI method).The results showed that crude protein content in mixed SCP biomassincreases with the increasing in fermentation time, otherwise it decreases with the increasing insubstrate carbon to nitrogen (C/N) ratio. Residual lignin content in mixed SCP biomass decreases from 7% to 0.63% during fermentationproceeded of 21 days. The highest crude protein content in mixed SCP biomasswas obtained at substrate C/N ratio 20:1 of 25%.

Fundamental understanding of distracted oxygen delignification efficiency by dissolved lignin during biorefinery process of eucalyptus

In this work, a fundamental understanding of oxygen delignification distracted by dissolved lignin was investigated. In the new biorefinery model of shortening kraft pulping integrated with extended oxygen delignification process, increasing content of residual lignin in the original pulp could result in enhanced delignification efficiency, higher pulp viscosity and less carbonyl groups. However, the invalid oxygen consumption by dissolved lignin could be increased with the increase of process temperature and alkali dosage. The normalized ultraviolet absorbance (divided by absorbance at 280 nm) also showed that the content of chromophoric group in dissolved lignin decreased with oxygen delignification proceeded, both of which indicated that dissolved lignin could enhance the invalid oxygen consumption. Therefore, a conclusion that replacement of the liquor at the initial phase of oxygen delignification process would balance the enhancement of delignification efficiency and invalid oxygen consumption was achieved.

Kinetic Study and Optimization of Catalytic Peroxide Delignification of Aspen Wood

It is established that the main regularities of the peroxide delignification of aspen wood in the temperature range of 70–100°С in the presence of dissolved (H2SO4) and solid (TiO2) catalysts are similar. With an increase of the temperature, the concentration of hydrogen peroxide and acetic acid, and the hydromodule (HM) values, as well as the duration of the process and the content of cellulose in the cellulose products, increase, while the content of the residual lignin decreases. Simultaneously, the total yield of cellulose products decreases independently of the nature of the catalyst. Delignification processes are satisfactory described by the first-order equation. A sufficiently high activation energy (88 kJ/mol in the presence of H2SO4 and 75 kJ/mol in the presence of TiO2) indicates the absence of significant external diffusion constraints in the selected conditions. The optimal conditions of obtaining cellulose products with a low content of residual lignin from aspen wood are found by the calculation methods. It is shown by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) that the structure of cellulose products obtained corresponds to the structure of industrial microcrystalline cellulose. In the optimal conditions, a high-quality cellulose product can be obtained in mild conditions (the temperature is 100°С, atmospheric pressure) by using a safer and technological TiO2 catalyst instead of a sulfuric acid catalyst.

Chemical composition of oriental spruce (Picea orientalis) and oak (Quercus spp.) barks

In this study, the chemical composition of bark from oriental spruce (Picea orientalis), which occur as a result of logging production of forestry enterprises, and oak (Qercus spp.) bark, which are industrial waste of the wood panel industry after board production, were analyzed by wet chemical analysis of wood and analysis methods of phenolic compound. Ash content values of the barks obtained from Artvin and Trabzon area were 4.31% and 3.99%, respectively, while the oak bark samples were 10.02%. Hot water solubility of the spruce bark samples were higher than the oak bark samples. Residual lignin contents of Artvin spruce, Trabzon spruce, and oak were 19.53%, 20.61%, and 18.49%, while α-cellulose contents were 37.28%, 37.92%, and 41.59%, respectively. The results of the total phenol content and butanol-HCl assay showed that Artvin spruce barks had higher values than other bark samples. As hydrolysable tannins, there were gallo tannin in the samples of spruce and oak barks whereas ellagic tannin content has not been determined.

Effect of lignin on the morphology and rheological properties of nanofibrillated cellulose produced from γ-valerolactone/water fractionation process

The influence of lignin content on nanocellulosic fibril morphology, charge, colloidal stability and immobilization has been systematically investigated employing a series of nanofibrillated cellulose (NFC) with varying residual lignin content and compared to those of NFC made from fully bleached pulp. The lignin-containing pulps were obtained from the fractionation of Eucalyptus globulus wood chips in gamma-valerolactone (GVL)/water under the same conditions, they differ by the intensity of washing for lignin removal. The reference pulp originated from another cook of eucalyptus wood chips, and was fully bleached with a short Elemental-Chlorine-Free (ECF) sequence. All the pulps have a comparable hemicellulose-to-cellulose ratio and CED viscosity. NFC suspensions of 1 wt% concentration were mechanically produced from fluidization. The results indicated that the fibrils morphology, thickness and corresponding flocculation within NFC suspensions was highly influenced by the presence of lignin unevenly distributed on the fibril surface and within the suspension as particles. The presence of lignin in NFC suspension had a large impact on the rheology and dewatering of the NFC. Samples with high lignin content had distinguishable viscoelastic properties due to the greater flocculation of thicker fibrils and lower gel-like characteristics, with better dewatering properties.

Production of cellulose pulp from agribusiness waste: experimental analysis of factors affecting the characteristics of pulp for absorbent purposes

Sustainable production is a recurrent theme in industrial engineering. Commercial production of canned palm hearts generates an amount of waste from the leaf sheaths that envelop the heart of palm, which can be used to produce cellulose pulp then reducing environmental impacts. This study aims to examine the feasibility of cellulose pulping from King Palm leaf sheaths to obtain a fiber with absorbent capacity and low residual lignin content, as well as demonstrate the influence of the controllable process factors on the response variables analyzed through the formulation of n-dimensional equations and surfaces which permitted the optimization of the variables of interest. The response variables were selected in order to characterize the fiber obtained according to degree of delignification, absorption capability and speed and apparent density. The results indicated that the pulps obtained from the processes proposed although didn’t meet the quality standards required for absorbent pulps, since values are lower than those established in the research hypotheses, is very promising. This attempt raises the discussion around the role that industrial engineering professionals and researchers may play in the agribusiness waste recovery and recycling. Moreover it provides useful information for re-planning of experiments in search for extraction optimization of this or similar agribusiness wastes.

Preparation of Eucalyptus pulp by mild condition of low-temperature, atmospheric pressure, and short-reaction-time with high-boiling-point solvent and pulp properties

Chemical pulp was prepared by the low-temperature, atmospheric pressure, and short reaction time pulping of Eucalyptus wood chips using a high-boiling-point solvent. The pulping conditions and pulp properties were evaluated. After the digestion of the Eucalyptus chips, pulp containing 6% residual lignin was obtained in 59.6% yield. It exhibited a low shive content and a sufficiently pulped appearance. With subsequent digestion at 110 °C for 60 min, the shive content further decreased, and fiber bundles disintegrated by simple mechanical stirring. The fiber length and width of the pulp were 500–577 and 20.1–27.9 μm, respectively, and the fiber roughness was 8.8–16.8 mg/100 m. The degree of crystallization of the pulp proportionally increased with cooking temperature. The brightness of the pulp with ~ 6% residual lignin content was greater than 52% ISO, and the zero-span tensile strength and viscosity gradually increased with pulping time.

Exploring an oxidative bleaching treatment for Chilean bamboo: a source of cellulose for biofuel generation and the nanotech industry

Quila (Chusquea quila) is a very abundant native Chilean bamboo species. This work reports on a delignification process which can be applied to quila to produce crystalline cellulose, an important resource for obtaining cellulose nanofibres or nanocrystals. Alternatively, the crystalline cellulose can then be subjected to fermentation processes, making it a useful raw material for biofuel production. The treatment studied is an oxidative treatment at low concentration (15% v/v), for short time periods (10, 20 min) and at temperatures between 100 and 140 °C, which produces alpha-cellulose fibres with high crystallinity (over 70%) and low residual lignin content (< 2%). The morphology of the cellulose fibres was analysed by scanning electron microscope, revealing a smooth surface containing many fibrils. Infrared spectroscopy was used to identify functional groups, showing that almost 99% of the lignin was removed. The crystallinity index of the cellulose fibres after the reaction was up to 79%, making it an excellent raw material for processing cellulose nanofibres required by the emerging nanotech industry. Carbohydrate analysis revealed 86% glucose and 14% xylose, which makes quila a promising candidate as a precursor for biofuel generation.

Transformation of Sugar Maple Bark through Catalytic Organosolv Pulping

The catalytic organosolv pulping of sugar maple bark was performed adopting the concept of forest biorefinery in order to transform bark into several valuable products. Our organosolv process, consisting of pre-extracting the lignocellulosic material followed by pulping with ferric chloride as a catalyst, was applied to sugar maple bark. The pre-extraction step has yielded a mixture of phenolic extractives, applicable as antioxidants. The organosolv pulping of extractives-free sugar maple bark yielded a solid cellulosic pulp (42.3%) and a black liquor containing solubilized bark lignin (24.1%) and products of sugars transformation (22.9% of hemicelluloses), mainly represented by furfural (0.35%) and 5-hydroxymethyl furfural (HMF, 0.74%). The bark cellulosic pulp was determined to be mainly constituted of glucose, with a high residual lignin content, probably related to the protein content of the original bark (containing cambium tissue). The biorefinery approach to the transformation of a solid bark residue into valuable biopolymers (lignin and cellulose) along with phenolic antioxidants from pre-extraction and the HMF derivatives from black liquor (applicable for 2,5-diformylfuran production) is an example of a catalytic process reposing on sustainable engineering and green chemistry concepts.

Chemical Pulping Advantages of Zip-lignin Hybrid Poplar.

Hybrid poplar genetically engineered to possess chemically labile ester linkages in its lignin backbone (zip‐lignin hybrid poplar) was examined to determine if the strategic lignin modifications would enhance chemical pulping efficiencies. Kraft pulping of zip‐lignin and wild‐type hybrid poplar was performed in lab‐scale reactors under conditions of varying severity by altering time, temperature and chemical charge. The resulting pulps were analyzed for yield, residual lignin content, and cellulose DP (degree of polymerization), as well as changes in carbohydrates and lignin structure. Statistical models of pulping were created, and the pulp bleaching and physical properties evaluated. Under identical cooking conditions, compared to wild‐type, the zip‐lignin hybrid poplar showed extended delignification, confirming the zip‐lignin effect. Additionally, yield and carbohydrate content of the ensuing pulps were slightly elevated, as was the cellulose DP for zip‐lignin poplar pulp, although differences in residual lignin between zip‐lignin and wild‐type poplar were not detected. Statistical prediction models facilitated comparisons between pulping conditions that resulted in identical delignification, with the zip‐lignin poplar needing milder cooking conditions and resulting in higher pulp yield (up to 1.41 % gain). Bleaching and physical properties were subsequently equivalent between the samples with slight chemical savings realized in the zip‐lignin samples due to the enhanced delignification.

The utility of selected kraft hardwood and softwood pulps for fuel ethanol production

Seven kraft hardwood (two poplar species, aspen, beech, and birch) and softwood (pine, bleached and unbleached) pulps were converted to ethanol to evaluate the effect of botanical origin and residual lignin content in a cellulosic pulp on ethanol yield and raw spirit composition. Successive steps of this process, such as (I) kraft pulping (by the sulfate method), (II) enzymatic saccharification, (III) alcohol fermentation and (IV) alcohol distillation were performed using a modified 15l reactor. The highest ethanol yield was obtained from the bleached pine pulp (nearly 0.46g/g d.w. pulp, 0.20g/g d.w. wood) while only 0.04g ethanol/g d.w. pulp was obtained from the unbleached pine pulp (only around 0.02g/g d.w. wood). Ethanol yields from the hardwood pulps were around 0.24–0.26g/g d.w. pulp that corresponded to 0.11–0.14g/g d.w. wood. The modified bioreactor equipped with an attachment enabling distillation of ethanol from the fermentation broth, may be used for production of fuel ethanol from superfluous and/or low quality woodchips and cellulosic pulps that cannot be used for paper production.