Lignin For Use Research Articles

Synthesis of basic amino acid-grafted lignin for use as a high-performance pigment dispersant.

Lignin is a promising dispersant due to its hyperbranched polymer structure, low cost, renewability and abundant availability. However, its use is limited by its broad molecular weight distribution, inhomogeneity, and low content of hydrophilic functional groups. In this work, lignin was functionalized with alkaline amino acids (EHL-AA) to enhance water solubility and molecular weight uniformity. The results showed that EHL-AA significantly improved the dispersion of pigment Red 57:1 (P.R.57:1) in aqueous solutions, reducing the required dosage by 50 % compared to commercial small-molecule dispersants. Additionally, histidine modified lignin (EHL-His) exhibited superior stability for P.R.57:1 compared to commercial lignosulfonate (REAX 85A). Molecular dynamics simulations further revealed that showed that EHL-His had the highest electrostatic potential difference and the largest absolute value of negative ESP. The adsorption of EHL-His onto the P.R.57:1 surface followed the pseudo-second-order kinetic model and the Langmuir model, with EHL-His showing a higher Langmuir constant (b) than REAX 85A, indicating the strongest interaction with the pigment. In summary, this work advances pigment dispersion technology and promotes the high-value utilization of lignin.

UV-absorption Capacity of Selected Crude and Functionalized Lignin for Use in Sunscreens

The most commonly used commercial sunscreen agents are aromatic compounds oxybenzone and octinoxate, as they offer a wide range of protection in the UV spectrum. However, oxybenzone has the highest rate of skin irritation, while octinoxate has poor photostability. Oxybenzone is also a genotoxicant and skeletal endocrine disruptor to corals. Appropriate, less toxic and preferentially biorenewable alternatives should be recommended. Lignin, an abundant byproduct of pulp and biorefinery industries, is expected to be an effective replacement for oxybenzone and octinoxate due to its aromatic structure, which, in synergy with a wide variety of functional groups, produces the absorption of energy in the entire UV region. Additionally, lignin is a biocompatible polyphenolic with a strong radical quenching ability, i.e., anti-oxidizing potential. Therefore, it is a promising replacement for synthetic chemicals in cosmetics, sunscreen, and other applications. The UV absorption analysis of selected crude and functionalized lignin samples was conducted, and the results were compared to those of commercially used UV-absorption agents—oxybenzone and octinoxate. The results showed that the total absorption capacity of the lignin samples is lower by 6.4x and 16.3x compared to oxybenzone and octinoxate, respectively; however, it covers a wide absorption range in the UV spectrum. The lignin samples also showed good photostability and color stability, in contrast to the observed yellowing of octinoxate after 3 hours of exposure to sunlight. The UV spectra of some of the lignin samples indicate that their UV absorption capacity was enhanced by as much as 13.31% after exposure to sunlight.

Evaluating the effect of paper waste lignin in hot mix asphalt

Asphalt is a viscoelastic material which performs to resist rutting, fatigue cracking, and moisture susceptibility under different loading and temperature conditions. The use of innovative and renewable pavement construction materials is inevitable due to high axle loads, rapidly increasing traffic volumes, and varying climatic conditions. This study aims to assess the effect as well as the optimum dosage of paper waste lignin for use in hot mix asphalt (HMA). Lignin from the paper industry with dosage ratios of 5, 10, 15, and 20%, was utilized to study the effect of the addition of lignin to the asphalt binder. Virgin and lignin-modified binder samples, before and after the aging process, were subjected to physical testing through penetration, softening point, ductility, viscosity and specific gravity and rheological characteristics through dynamic shear rheometer (DSR), bending beam rheometer (BBR), and rational viscometer (RV). The fractional composition was assessed through saturates, aromatics, resins and asphaltenes (SARA) fractional composition technique. Statistical analysis was also performed to find correlation of different physical and rheological parameters. Furthermore, based on optimum dosage, the performance of asphalt mixtures was studied against rutting, fatigue cracking, and moisture susceptibility. The results indicated that the addition of lignin has improved the physical properties significantly. The amount of asphaltene decreased and aromatics increased in SARA fractional analysis. Moreover, the Colloidal Instability Index (CII) has also indicated a stable structure of the binder. The rheological characteristics are improved after modification. The asphalt mixture tests revealed that addition of lignin with optimum dosage (10%) has improved the performance against rutting, fatigue cracking and moisture susceptibility. Statistical analysis indicated good co-relation among different physical and rheological parameters. This study concludes that 10% dosage is the optimum dosage that can successfully replace the virgin asphalt binder for performance of hot mix asphalt.

Valorisation and Thermal Responsiveness of Lignin from Elaesis guineensis

In recent years, advancement in material technology and a better understanding of material propertiescoupled with the quest for bio-compactible materials has driven research towards valorisation of agro-waste like empty palm fruit bunch (EPFB). Elaesis guineensis was a potential source of biomass and was classified as an environmental pollutant and disposal burden. In this study, the valorisation of Elaesis guineensis and its thermal responsiveness as lignin for use as a filler in polymer composites are examined. Lignin from EPFB was extracted via acid hydrolysis, using Di ethyl ether ((C2H5)2O) and HCl as the pretreatment solvent. The thermal stability, crystallinity, heat flow, chemical composition, and functional group of the extracted lignin were studied for treated and untreated EPFB samples using techniques like; Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), X- ray diffrraction (XRD), X-Ray Fluorescence Spectroscopy (XRF) and Differential Scanning Calorimetry (DSC). The percent yield of 23% obtained in this work is within the range specified in literature (20.1-23.8%) using sodium hydroxide(NaOH) and calcium hydroxide (Ca (OH)2) for alkali treatment. Results of the FTIR analysis of all samples in reference to the wave numbers of lignin are in good agreement with those stated in the literature. The stretching patterns alsoindicate the presence of compounds like phenols, hydroxides, and methyl groups, which are characteristics of lignin compounds. By comparing with the cellulose standard available in the database of the XRD system, two main peaks were observed from the XRD patterns at 2θ = 22.3 and 2θ = 26.7 representing peak 002 for hemicellulose and 011 for lignin, respectively corresponding to the amorphous region of hemicellulose and lignin while peaks I002 represent the crystalline region of cellulose. From the study, it was inferred that the thermal stability of extracted lignin with a Tg of 400C is higher compared to the samples treated with di ethyl ether and untreated EPFB having a Tg of 200C. The extracted lignin has a maximum decomposition temperature of 400oC, which makes it suitable as a filler in polymer composites.

High-performance adhesives modified by demethylated lignin for use in extreme environments

Lignin-modified epoxy resin (LER) is a promising alternative to bisphenol A in the preparation of epoxy resins.

Improving UV Curing in Organosolv Lignin-Containing Photopolymers for Stereolithography by Reduction and Acylation.

Despite recent successes in incorporating lignin into photoactive resins, lignin photo-properties can be detrimental to its application in UV-curable photopolymers, especially in specialized engineered resins for use in stereolithography printing. We report on chemical modification techniques employed to reduce UV absorption by lignin and the resulting mechanical, thermal, and cure properties of these modified lignin materials. Lignin was modified using reduction and acylation reactions and incorporated into a 3D printable resin formulation. UV–Vis absorption at the 3D printing range of 405 nm was reduced in all modified lignins compared to the unmodified sample by 25% to ≥ 60%. Resins made with the modified lignins showed an increase in stiffness and strength with lower thermal stability. Studying these techniques is an important step in developing lignin for use in UV-curing applications and further the effort to valorize lignin towards commercial use.

Pyrolysis Characteristics of Industrial Lignin for Use as a Reductant and an Energy Source for Future Iron Making

The purpose of this study is to explore the possibility of using industrial lignin instead of pulverized coal as a reducing agent for the production of direct reduced iron (DRI), thus reducing CO2 emissions. The pyrolysis characteristics and kinetics of pulverized coal and industrial lignin were studied by nonisothermal thermogravimetry. In the three stages of pyrolysis, the weight loss rate of industrial lignin is higher than that of pulverized coal. The volatile matter of industrial lignin is easier to release than that of pulverized coal, but the coking process is longer than that of pulverized coal. The activation energies of pyrolysis of Lu’an anthracite (LA), Shen’mu bituminous coal (SM), alkali lignin (AL), and magnesium lignosulfonate (ML) were 71.10, 70.30, 55.20, and 37.34 kJ·mol–1 at the middle-temperature stage, and 133.64, 98.31, 57.78, and 46.68 kJ·mol–1 at the high-temperature stage, respectively. After pyrolysis, a few nanometer thick carbon film structure appears in alkali lignin coke, which is conducive to the reduction of iron ore powder.

Development of lignin‐based carbon foam for use as an FRP sandwich core material

AbstractSandwich‐structure materials consist of a high‐strength skin material and a lightweight core material. The advantages of sandwich structures are known to include excellent mechanical properties and low weight, the latter of which is the result of a lightweight core. However, soft‐core members such as plastic foam materials have low rigidity and therefore may not exhibit adequate functionality when used in sandwich structures. This research sought to reduce environmental impact and to facilitate sustainable development by developing a method for fabricating high‐strength carbon foam using alkali lignin for use as an FRP sandwich core and enhancing the mechanical properties of the carbon foam with short glass fiber. PMMA particles decomposed at high temperatures to leave gaps, creating carbon foam with a closed structure. The relationship between PMMA particle size and foam pore size was investigated by observing cross‐sections of the foam.

Endo-xylanase Enzyme Production using Agroindustrial Biomass as Feedstock by Kitasatospora sp.

Endo-β-1, 4-xylanases is an enzyme that depolymerize xylan, a major component of lignocelluloses. Lignoselulose is a great source of cheap carbohydrate and thus has been used over the past decade as a raw material for the production of high value products, such as enzymes. However, lignocelluloses are a highly recalcitrant material that is extremely difficult to depolymerize. By using proper pretreatment, lignocelluloses from agroindustrial biomass can replace conventional carbon sources in media preparation for enzyme production. In this study, we used three kinds of agroindustrial biomass, such as sorghum variety of Buleleng, sorghum variety of JP, rice straw LIPI GO1 and these biomasses were pretreated with acid to remove a portion of lignin for use as a carbon source to endoxylanase production. The production of xylanase Kitasatospora sp. under submerged fermentation was investigated with different carbon sources using agroindustrial biomass. Optimization steps included studies carbon source concentration and pH medium fermentation. The optimized condition of enzyme production was obtained using the sorghum variety Buleleng biomass at 2% concentration and pH medium is 9.0 with activity 3. 04 U/mL.

A concise review of current lignin production, applications, products and their environmental impact

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.

Improving Lignin Homogeneity and Functionality via Ethanolysis for Production of Antioxidants

As an antioxidant material, lignin has some structural disadvantages such as heterogeneity, high molecular weight, and low functionality. We propose a simple method based on ethanolysis pretreatment (120, 160, and 200 °C for 1 h) of lignin by which the structure, especially the molecular weight distribution and phenolic hydroxyl content (Phe-OH) of lignin, are improved. After reaction, over 80 wt % structurally modified lignin (solubilized lignin: SL) was recovered from raw lignin, and its homogeneity as well as Phe-OH content increased. The antioxidant activity of SLs was investigated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability. Interestingly, DPPH radical scavenging capacities of SL produced at 160 °C (IC50 = 0.016 mg/mL) was close to commercial antioxidants such as ferulic acid (IC50 = 0.010 mg/mL) and guaiacol (IC50 = 0.013 mg/mL), suggesting that ethanolysis pretreatment was effective in modifying the structure of lignin for use as antioxidant. We also performed experiments wit...

Reduction of Formaldehyde Emission from Particleboard by Phenolated Kraft Lignin

The aim of this study was the reduction of formaldehyde emission from particleboard by phenolated Kraft lignin. For this purpose, the lignin was extracted from black liquor and then modified by phenolation. During the urea formaldehyde (UF) resin synthesis different proportions of unmodified and phenolated Kraft lignins (10%, 15%, and 20%) were added at pH = 7 instead of the second urea. Physicochemical properties and structural changes of resins so prepared, as well as the internal bond (IB) strength and formaldehyde emission associated with the panels bonded with them were measured according to standard methods. The Fourier transform infrared (FTIR) analysis of lignin indicated that the content of O–H bonds increased in phenolated lignin while the aliphatic ethers C–O bonds decreased markedly in the modified lignin. Since both synthesis of UF resins and lignin phenolation are carried out under acid conditions, phenolation is an interesting way of modifying lignin for use in wood adhesive. The panels bonded with these resins showed significantly lower formaldehyde emission compared to commercial UF adhesives. The UF resin with 20% phenolated lignin exhibited less formaldehyde release without significant differences in internal bond strength and physicochemical properties compared to an unmodified UF resin. XRD analysis results indicated that addition of phenolated lignin decreased the crystallinity of the hardened UF resins.

Organic neem compounds inhibit soft-rot fungal growth and improve the strength of anthracite bricks bound with collagen and lignin for use in iron foundry cupolas.

To examine organic neem compounds for their effective growth inhibition of saprotrophic soft-rot fungi on anthracite bricks bound with collagen and lignin for use in iron foundry cupolas as an alternative fuel source. Azadirachtin, crude neem oil (NO), and clarified neem oil extract (CNO) were combined with copper to inhibit the growth of the soft-rot fungus, Chaetomium globosum. A synergistic interaction was observed between CNO and a low dose of copper on nutrient media (two-factor anova with triplicate replication: P < 0·05). Interaction was confirmed on lab-scale collagen-lignin-anthracite briquettes by measuring their unconfined compressive (UC) strength. The effective collagen strength of the briquettes was enhanced by applying CNO to their surface prior to inoculation: the room temperature UC strength of the briquettes was 28 ± 4·6% greater when CNO (0·4 mg cm(-2) ) was surface-applied, and was 43 ± 3·0% greater when CNO plus copper (0·14 μg cm(-2) ) were surface-applied. Surface application of CNO and copper synergistically prevents fungal growth on bindered anthracite briquettes and increases their room temperature strength. This novel organic fungicidal treatment may increase the storage and performance of anthracite bricks in iron foundries, thereby saving 15-20% of the energy used in conventional coke production.

A Study of Carbonized Lignin as an Alternative to Carbon Black

The production of biobased carbonaceous powder from bioethanol coproduct lignin for use as a substitute for fossil fuel-derived conductive carbon black filler is examined. The synthesis procedure used for the formation of biobased carbon black is studied in order to obtain properties similar to conventional carbon black. Characterization of the carbon material after varying carbonization temperatures and ball milling times was investigated to optimize carbon size, surface area, and thermal and electrical conductivity. The optimized carbonized ball milled lignin had a carbon content greater than 90% with the majority of the carbon atoms in the sp2 hybridized state. The carbonized ball milled lignin exhibited a surface area 882% larger and a thermal conductivity 36% greater in comparison to the conductive carbon black tested, while the electrical conductivity was 9.5 S m–1 lower for the carbonized ball milled lignin. This research has demonstrated the possibility of producing biobased carbon black as a pote...

Effect of irradiation on the composition and thermal properties of softwood kraft lignin and styrene grafted lignin

ABSTRACTLignin is an abundant, underutilized natural resource that has potential to be used as a biomaterial but is currently hampered in its use by not being uniform in structure and composition and is thermally unstable due to phenolic group. To address these issues and modify its thermal properties, softwood kraft lignin was modified using γ‐irradiation at low doses with and without styrene present and characterized. Irradiation of kraft lignin alone with γ‐radiation shows an initial decrease in molecular weight due to chain scission up to about 10 kGy followed by an increase in molecular weight due to crosslinking. NMR results indicate a decrease of about 15% in the OH content of the lignin with 30 kGy irradiation. Thermal properties such as Tg, free volume and ΔCp follow accordingly. Irradiation at very low dosages was determined to facilitate the grafting of styrene monomer to lignin, decreasing the OH content by 23%. This effect increased the hydrophobicity of the material, depressed the value of Tg, increased the ΔCp, increased the mobility in the liquid state, and made the material more thermally stable relative to the lignin alone, thus improving its processability at high temperatures. Both the irradiation of lignin alone and the grafting of styrene to lignin increased the yield of mass during pyrolysis and the activation energy for mass loss relative to untreated lignin alone. This work has demonstrated that the application of low dosages of γ‐irradiation is a promising method to attach functional molecules onto lignin for use in various applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39743.

Cost estimates of kraft lignin recovery by ultrafiltration

Climate change and endeavours towards a sustainable society have brought the interest of wood-based biorefineries to the fore. Lignin is the main energy carrier in chemical pulp mills. Today, the heat value of lignin is commonly recovered in the recovery boiler of the mill. However, interest in the extraction of lignin for use as an external biofuel and in speciality chemicals is growing. Lignosulphonates have been isolated by ultrafiltration from spent liquor in sulphite pulp mills for decades, whereas kraft lignin is mainly extracted by precipitation. The isolation of kraft lignin by ultrafiltration is currently attracting increasingly greater interest because lignin can be extracted from pulping liquors at almost all positions in a pulp mill using ceramic membranes, without altering the pH or temperature of the liquor. In this work hardwood lignin was recovered from two process streams in a kraft pulp mill by ultrafiltration with a ceramic membrane with a cut-off of 15,000 Da. It was shown that lignin can be recovered from a cooking liquor at a cost of about 60 € per tonne of lignin and from black liquor withdrawn from the evaporation unit at 33 € per tonne.

Elucidation of the structure of cellulolytic enzyme lignin

Abstract Cellulolytic enzyme lignin (CEL) and milled wood lignin (MWL) were prepared by three different ball-milling methods. The structure of CEL at various yields was elucidated and compared with MWL using wet chemical analysis, FTIR and solution-state NMR techniques. Results show that ball milling of wood degrades β-O-4 structures in lignin. However, even after extensive ball milling, less than 25% of the β-O-4 structures were degraded. The extent of degradation was less for softwood than for hardwood lignin. Extractable lignin yield, either MWL or CEL, was the best way to assess the extent and effect of ball milling. CEL is preferred over MWL, as it can be isolated in higher yield with less degradation. CEL was isolated at yields ranging from 20% to 86%. Over this range the CEL had similar structures, suggesting that lignin in the secondary wall is uniform in structure. The residual enzyme lignin (REL) was structurally different from CEL and may originate mainly from the middle lamella. In this paper we propose a new procedure for the isolation of lignin for use in structural studies, whereby wood is sufficiently milled and successively extracted to produce three lignin fractions representing the total lignin in wood.

Preliminary evaluation of an H 2SO 4-wood saccharification lignin for use in phenolic resins

The solid residue from a two-stage, sulfuric acid-based wood hydrolysis process was tested for its utility in phenol-formaldehyde resins. It yielded between 5 and 60 weight % of the residue in the form of a homogeneous fraction when extracted with different organic solvents or alkali, and thus varied in relation to molecular weight. A 40% fraction soluble in aqueous ethanol was structurally more condensed than comparable hardwood lignin isolated by a kraft or organosolv process. This fraction proved to be relatively unreactive with formaldehyde and phenol, and this was attributed to its hardwood and chemically condensed nature. Phenolic resins were formulated at a 45% solids content in a two-stage resin cook procedure with >50% replacement of phenol by lignin. These resins were evaluated by thermal analysis with regard to cure, and by shear testing of laminated blocks with regard to dry strength. Results with the best resins revealed minor differences as compared to control phenol-formaldehyde resins in terms of viscosity, cure rate, activation energy of the curing reaction, and dry shear strength performance. Dry strength characteristics were found to be more variable than those obtained using phenol-formaldehyde resins, and network formation characteristics were inferior to other lignin products. The significance of these differences needs to be evaluated under commercially realistic conditions usually employed in plywood manufacturing, and in larger scale tests.