Extraction and characterization of lignin from different biomass resources (original) (raw)
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The potential of organosolv and kraft eucalyptus and spruce lignin as feedstock for polymeric materials and biofuel applications was assessed. Proximate analysis was used to predict the heating values and char formation. Chemical modification, based on the esterification reaction with methacryloyl chloride, was applied to introduce vinyl groups into the lignin macromolecules for enhanced reactivity. Kraft eucalyptus and spruce lignins had a more condensed structure than organosolv lignins, which resulted in greater thermal stability for these lignins. For different species within the same process, the thermal parameters showed a correlation with certain structural and compositional parameters (ash and sugars content, molecular weight and degree of condensation). Organosolv spruce lignin produced the highest heating value of 24 MJ/Kg, which is suitable for biofuel applications. The content of phenolic OH groups was higher for kraft lignins and especially higher for softwood lignins, both organosolv and kraft. The degree of methacrylation, estimated from the content of vinyl groups per C9 lignin unit, was significantly greater for organosolv lignins than for kraft lignins despite the higher OH-groups content in the latter.
A Review on the Lignin Biopolymer and Its Integration in the Elaboration of Sustainable Materials
Sustainability, 2021
Lignin is one of the wood and plant cell wall components that is available in large quantities in nature. Its polyphenolic chemical structure has been of interest for valorization and industrial application studies. Lignin can be obtained from wood by various delignification chemical processes, which give it a structure and specific properties that will depend on the plant species. Due to the versatility and chemical diversity of lignin, the chemical industry has focused on its use as a viable alternative of renewable raw material for the synthesis of new and sustainable biomaterials. However, its structure is complex and difficult to characterize, presenting some obstacles to be integrated into mixtures for the development of polymers, fibers, and other materials. The objective of this review is to present a background of the structure, biosynthesis, and the main mechanisms of lignin recovery from chemical processes (sulfite and kraft) and sulfur-free processes (organosolv) and des...
A concise review of current lignin production, applications, products and their environmental impact
Industrial Crops and Products, 2019
Lignin is the second most abundant natural material on the earth. Commercially, it is generated as a waste product from the paper and ethanol production. The worldwide production of lignin is approximately 100 million tonnes/year valued at USD 732.7 million in 2015. It is expected to reach $913.1 million by 2025 with compound annual growth rate (CAGR) of 2.2%. Two principal categories of lignin are ligno-sulphonate (˜88%) and kraft lignins (˜9%), however a new category organosolv (˜2%) is now gaining popularity due to the production of second generation biofuels (bioethanol production). The organosolv lignin segment is expected to experience the highest growth over the coming years, at an estimated CAGR of over 5% from 2016 to 2025. Chemically lignin is a polyaromatic macromolecule. The complexity and richness of its functional groups makes it attractive for converting into a variety of value added products like high performance carbon fiber, bio-oil, vanillin, and phenolic resin to name a few. Over the years lignin has been predominantly burnt as fuel for heat and power. Less than 2% of the available lignin was sold, primarily in the formulation of dispersants, adhesives and surfactants. However, in the last decade lignin-based research and new product development has picked significant momentum due to the bio-refinery concept as aging pulp and paper mills need to diversify their products portfolio to maintain their vitality. The emerging biofuel/bioenergy technologies are working to develop value-added co-products from lignin and bio-oil as a means of making the processes more cost effective. There is a resurgence in the demand for lignin for use in binders, adhesives, bioplastics, concrete admixtures and biomedical applications. Effective "upstream" and "downstream" valorization techniques are facilitating fine tuning of lignin as a building block for high value chemicals. Other market dynamics driving lignin use are stringent regulations for dust control, demand for high quality concrete admixtures and dispersants, and carbon rich products (activated carbon, carbon filer, resins etc.). To further accelerate development of lignin based products consumer awareness and gap between research and development and consumer products need to be reduced. Despite the growing body of research on the possibilities of
Review Engineering Plant Biomass Lignin Content and Composition for
2015
Lignin is an aromatic biopolymer involved in providing structural support to plant cell walls. Compared to the other cell wall polymers, i.e., cellulose and hemicelluloses, lignin has been considered a hindrance in cellulosic bioethanol production due to the complexity involved in its separation from other polymers of various biomass feedstocks. Nevertheless, lignin is a potential source of valuable aromatic chemical compounds and upgradable building blocks. Though the biosynthetic pathway of lignin has been elucidated in great detail, the random nature of the polymerization (free radical coupling) process poses challenges for its depolymerization into valuable bioproducts. The absence of specific methodologies for lignin degradation represents an important opportunity for research and development. This review highlights research development in lignin biosynthesis, lignin genetic engineering and different biological and chemical means of depolymerization used to convert lignin into biofuels and bioproducts.
Polymer Composites, 2022
Lignins are the most important aromatic renewable natural resource today, serving as a sustainable, environmentally acceptable alternative feedstock to fossil-derived chemicals and polymers in a vast scope of value-added applications. Lignin is a biopolymeric molecule that, together with cellulose, is a fundamental component of higher vascular plants structural cell walls. It can be extracted from by-products of the pulp and paper industries, agricultural waste and residues, and biorefinery products. Lignin properties may vary depending on source and extraction method with carbon and aromatic as the main compositions in lignin structure. These rich compositions make lignin more valuable, allowing for the creation of high-value-added green composites. However, the complex structure of lignin creates low reactivity to interact with crosslinker, and hence chemical modification is substantial to overcome this problem. This review aimed to present and discuss lignin structure, variation of lignin chemical properties regarding its source and extraction process, recent advances in chemical modification of lignin to enhance its reactivity, and potential applications of modified lignin for manufacturing value-added biocomposites with enhanced properties and lower environmental impact, such as food handling/packaging, seed coating, automotive devices, 3D printing, rubber industry, and wood adhesives.
Advances in Materials Science and Engineering
After cellulose, lignin is the most commonly used natural polymer in green biomaterials. Pulp and paper mills and emerging cellulosic biorefineries are the main sources of technical lignin. However, only 2–5% of lignin has been converted into biomaterials. Making lignin-based polymer biocomposites to replace petroleum-based composites has piqued the interest of many researchers worldwide due to the positive environmental impact of traditional composites over time. In composite development, lignin is being used as a filler in commercial polymers to improve biodegradability and possibly lower production costs. As a natural polymer, lignin may have different properties depending on the isolation method and source, affecting polymer-based composites. The application has been affected by the characteristics of lignin and the uniform distribution of lignin in polymers. The review’s goal was to provide an overview of technical lignin extraction, properties, and its potential appropriate ut...
Lignin as a base material for materials applications: Chemistry, application and economics
Industrial Crops and Products, 2008
Feedstock Sector Polymer composites a b s t r a c t Lignin has long laboured under the label of "waste material". However, as part of the thematic network EUROLIGNIN, a survey and desk study was undertaken to assess the changes and patterns in the utilisation of lignin with respect to materials applications. This showed that over the last 10-15 years there has been an explosion of research into, and commercialisation of, lignin-based products and processes which add significant value to a material that was previously, and continues to be, used as a low-value fuel for pulping boilers. The innate chemistry of lignin, a phenolic heteropolymer, has allowed it to make inroads into the high value polymer industries whilst continuing to act as feedstock material for the binder industries. Indeed the replacement of phenolics by lignin in resins systems is economically attractive with the phenolic resins market utilising approximately 2.52 M tonnes in 2001. Currently lignin, predominantly as lignosulphates, is used as a binding and dispersing agent in different industries with approximately 1 M tonnes (on a 100% solids basis) used annually, for example, in concrete admixtures. These and other applications will be discussed and expanded upon here with emphasis on both the economics of the markets and what is still required for lignin to mature as a valuable resource in its own right.
Isolation and characterization of herbaceous lignins for applications in biomaterials
Industrial Crops and Products, 2013
The imminent industrial production of cellulosic ethanol from annual plants will generate massive amounts of herbaceous lignins that will have to be valorized. However, the chemical and physical properties of herbaceous lignins are much less known than those of wood lignins. In the present study, organosolv lignins were extracted from wheat, triticale, corn, flax, and hemp residues using microwave irradiation under similar conditions. The extracted lignins were extensively analyzed by FT-IR, 31 P NMR, gel permeation chromatography, thermogravimetric analysis, and elemental and carbohydrate analysis to determine their applicability in polymers. All lignins were of high purity with low sugar, sulfur, and ash content. Corn, hemp, and flax lignins were found to contain high concentrations of non-methoxylated phenolic groups, syringyl phenolic groups, and aliphatic OH groups, respectively, making them promising candidates for production of phenolic resins, stabilization of polyolefins, and polyurethane synthesis, respectively. Triticale or wheat lignins were less specific, with a balanced content of OH groups, which makes them applicable to polyester synthesis.
IJAEM, 2021
In the last century, the major achievement of the material science is the generation of number of synthetic polymers and composites which has revolutionized the world. But these materials are a potent source of pollution also, as these are non-biodegradable under natural environmental conditions. Lignin is one of the major constituents of natural and biological fibers, along with cellulose, hemicellulose, pectin, xylan, inulin etc. It is universal and the most essential part of plant cell walls of all types, making it one of the most common natural polymers in the world. It is second only to cellulose in its abundance. The application of lignin and lignin materials as a natural fiber to utilize in synthesis of polymer composites has been topic of interest in recent past. The research focused on lignin materials synthesis is due to its easy availability, rigid structure, resistance to different chemicals, ecofriendly nature, cheap cost, easy extraction from plant polymers and its sustainability. The aim of this study is to provide a systematic review of use of lignin in synthesis of various lignin fiber reinforced polymer composites (LFPCs) and their applications. The comprehensive use of lignin in aerogels, lignin reinforced thermoplastic composites, thermoset composites, bioplastic composites, composite carbon nanofibers, and rubber composites will discussed in the text to come.