Search results for "Lignin"
showing 10 items of 149 documents
Hydrothermal liquefaction of wood using a modified multistage shrinking-core model
2020
Abstract Wood liquefaction in hot compressed water is modeled using the hydrolysis of Cellulose, Hemicellulose, and Lignin. These three components are reacted under catalyst-free subcritical conditions in a temperature range from 553 K to 640 K, and the heating rate ranges from 2 K/min to 6 K/min. Using a simplified reaction scheme, water-soluble products 1 (WSP), Biocrude, char, and gas are generated through intermediates with each wood component. A modified multistage shrinking core model is employed to simulate biomass particle degradation. The reaction and kinetic regime of the hydrothermal liquefaction 2 (HTL) process are treated separately for each wood component. Although the lack of…
Scanning probe microscopy of pine and birch kraft pulp fibres
2000
Abstract Fibres of the conventional pine and birch kraft pulps were characterized by scanning probe microscopy (SPM). The surface characteristics of these pulps taken at the early stages of pulping were compared with those from later stages of pulping (with or without subsequent oxygen/alkali delignification). It was observed that during delignification a granular surface structure was replaced by a fibrillar surface containing various disruptions. The granular and fibrillar regions were particularly well resolved by using phase imaging in tapping mode of SPM. It was concluded that the granular structure corresponded to surface lignin since the decrease in the relative amount of the granula…
Experimental and theoretical investigations of lignin-urea-formaldehyde wood adhesive: Density functional theory analysis
2021
Abstract In view of its chemical structure, lignin has recently become an interesting candidate for various applications. This work serves to optimize the isolation process of lignin from sugar industry by-product (bagasse can, molasses beet) applying alkali treatment. For this purpose, the effect of alkali and sulfuric acid concentrations have been studied ranging from 10% (w/v) to 20% (w/v) and 1.5 M–3 M, respectively. Moreover, the isolated lignins were characterized by different complementary analysis such as FT-IR and TGA/DTG. The aim behind this work is to reduce formaldehyde emissions and improving mechanical as well as physical properties of wood adhesive. Lignin was added with diff…
Chemical characterization and ultrastructure study of pulp fibers
2020
Abstract Understanding the ultrastructure and chemical characterization of pulp fibers is highly important in utilizing wood as a raw material in a wide scope of applications, such as forest biomass-based biorefineries and low-cost renewable materials. The observation of the ultrastructure is not possible without advanced microscopy and spectroscopy techniques. Therefore, this study focuses on exploring the ultrastructure of pulp fibers with helium ion microscopy (HIM) and scanning electron microscopy (SEM). For the analysis of chemical characterization in the pulp fibers, Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) were pe…
Reactive Layer Assembly Sustains an Interlocked Structure in Green Processed and Scalable High-Performance Layered Wood
2021
Wood can be processed into structural materials by partial removal of lignin and subsequent hot compression. The fundamental challenge of this process is achieving a cost-effective, green, and scal...
Numerical modeling and validation of hydrothermal liquefaction of a lignin particle for biocrude production
2021
Abstract Lignin liquefaction process under catalyst-free conditions in a temperature range from 573 K to 647 K is investigated with this mathematical model. Based on the theoretical understanding of the physical and chemical processes of the liquefaction process in subcritical temperatures, a comprehensive mathematical model for the decomposition of lignin by hydrolysis reaction pathway is developed on the results of a series of batch experiments. The model consists of four main sections. They are liquefaction of lignin particle, oily film, and inorganic (ash) layer formation behavior during the liquefaction, kinetic model to model further liquefaction process of initial products, and the l…
Valorization of Solanum Elaeagnifolium Cavanilles Weeds as a New Lignocellulosic Source for the Formulation of Lignin-Urea-Formaldehyde Wood Adhesive
2021
Solanum Elaeagnifolium Cavanilles (SE-Cav) is an invasive plant that has been developed in Mediterranean basin countries especially in Morocco. This weeds which belongs to lignocellulosic biomass a...
Characterization of lignin dissolved during alkaline pretreatment of softwood and hardwood
2015
Various alkaline pretreatments were applied to Scots pine (Pinus sylvestris) and silver/white birch (Betula pendula/pubescens) wood chips and the characterization of sulfur-free lignin dissolved was performed. The behavior of lignin during these pretreatments (alkali charge 1–8% NaOH, time 30–120 minutes, and temperature 130–150°C) was studied mainly in terms of lignin removal efficiency and molar mass distribution of dissolved lignin. The amount of lignin in pretreatment liquors increased along with an increase in the alkali charge of 0.8–4.4% and 0.6–3.4% of o.d. pine and birch wood, respectively. The most significant parameter affecting the molar mass of the dissolved lignin was shown to…
Effect of Lignin-Containing Media on Growth of Medicinal Mushroom Lentinula Edodes
2017
Abstract The effect of lignocellulose and lignin on growth of mycelium of mushroom Lentinula edodes and laccase activity in cultivation medium was studied. It was shown that cultivation of L. edodes mycelium in liquid nutrient medium with addition of 0.25-0.5% of kraft lignin increased mycelium biomass yield approximately two times compared with reference conditions without addition of lignin. Similar results were obtained in experiments in which 0.5% lignocellulose that remained after obtaining furfural, and 0.5% lignin that remained after obtaining furfural and glucose from wheat straw, were added to the nutrient medium. This effect was greater in the conditions of cultivation with good a…
Characterization of softwood and hardwood lignoboost kraft lignins with emphasis on their antioxidant activity
2014
Fractionation of softwood and hardwood LignoBoost kraft lignins, using sequential extraction with organic solvents of increasing hydrogen-bonding ability (dichloromethane, n-propanol, and methanol), was carried out. Using SEC, analytical pyrolysis, FTIR and UV/VIS spectroscopy, and chemical analytical methods, four fractions were obtained and characterized in terms of their yield, composition, functionality, lignin structural features, and antioxidant properties. In tests with free radicals (ABTS●+, DPPH●, O2●-) and the ORAC (oxygen radical absorbance capacity) assay, the high radical scavenging capacity of the lignin’s soluble fractions was demonstrated. The antioxidant activity of the fra…