Low-cost Lignin Research Articles

Preparation of manganese/nitrogen-sulfur carbon electrodes from black liquor of bamboo pulp for supercapacitors

Biomass-derived porous carbons from low-cost lignin are the promising candidate electrode for aqueous supercapacitors. Notably, the poor charge storage ability severely hinders the industrial production. The sodium lignosulphonate was firstly prepared by methylsulfonation with formaldehyde (HCHO) and sodium sulfite (Na2SO3). Then, lignin-based N-S co-doped porous carbon materials (LNSC) were prepared via one-step carbonization with sodium lignosulphonate as raw material and urea as a nitrogen source dopant and mild activator. And, MnCO3 nanowires were prepared and loaded on LNSC to fabricate manganese/nitrogen-sulfur carbon composites (LNSC/Mn-x) with high electrochemical performance. The prepared LNSC/Mn-40 was dominated by micro-mesopores with a total pore volume of 1.01 cm3 g−1 and a specific surface area of up to 770.68 m2 g−1. In a three-electrode system, LNSC/Mn-40 showed a specific capacitance of 234.92 F g−1 at 0.5 A g−1 in 6 M KOH electrolyte, greatly better than LNSC (151.98 F g−1 at 0.5 A g−1), while the symmetric supercapacitor demonstrated a maximum energy density of 7.21 Wh kg−1 at a power density of 5765 W kg−1 along with good cycling stability of 69.77 % capacitance retention for up to 10,000 cycles. The results suggested that lignin can be considered as an ideal candidate for porous carbon electrode for supercapacitors and reduce industrial production cost.

High-performance and economic biodegradable composites based on polybutylene adipate terephthalate and modified lignin

Polybutylene adipate terephthalate (PBAT) is a biodegradable polymer with promising properties, but its wide-spread application is limited by factors such as high cost, suboptimal mechanical characteristics, and slow biodegradation rate. In this study, these limitations are addressed by incorporating low-cost lignin, modified with an isocyanate compound, into PBAT via an extrusion process. By investigating the effects of varying isocyanate content on the lignin surface, the optimal modification conditions at room temperature are identified over 48 h. Additionally, the maximum lignin content (5 wt%) is determined within the composite to achieve a balance between mechanical, thermal, and biodegradation properties while also considering the economic and environmental feasibility of the polymer composite. The research delved into the examination of both the minimum selling price (MSP) and global warming potential (GWP) for all PBAT-mLigA composites. The optimized PBAT-mLigA composites exhibited a notable reduction of up to 7% in both MSP and GWP when compared to pure PBAT. The predominant determinants influencing the economic and environmental potentials of these composites are the pricing of PBAT and the ratio in which it is incorporated into the proposed composites.

ELECTROCHEMICALLY TREATED LIGNIN IN PHENOLIC RESINS FOR PLYWOOD PANELS

In achieving the European Union's goal of making Europe the first climate-neutral continent by 2050, the scientific community is striving to develop processes and products that are technologically and economically sustainable to replace/substitute fossil-based feedstocks. In this effort, the European project LIBERATE has demonstrated the commercial opportunities of converting low-cost lignin feedstocks into high-value bio sustainable chemicals such as vanillin and mixed phenolic derivatives.Lignin is the largest regenerative source of aromatic organics. In current wood pulping industries, lignin is underutilized and widely considered a side stream primarily exploited for its energy content. A promising approach for the synthesis of biobased fine chemicals is a depolymerisation process for lignin using sodium peroxodicarbonate (PODIC®), an electrochemically produced oxidiser. Within the LIBERATE project, SINTEF has built a pilot scale plant for the electrochemical lignin depolymerisation. The plant provided CHIMAR with the phenol-rich reactor product solution from both kraft and organosolv lignin, which was used as phenol substitutes with up to 50wt% in the formulation of phenol-formaldehyde (PF) resins. These resins have been able to produce successful plywood panels on a laboratory scale. Although their quality is somewhat lower than that of the reference material with traditional PF resin, this work showed that the use of lignin fractions obtained by electrochemical treatment in such an application is possible and promising.

POSS(epoxy)8 reinforced poly (butylene adipate-co-terephthalate)/lignin biodegradable films: Fabrication, enhanced mechanical properties and UV aging resistance

To reduce the white pollution, the eco-friendly biodegradable poly (butylene adipate-co-terephthalate) (PBAT)-based films had attracted increasing interests worldwide. However, the high-cost of the PBAT had limited the large-scale development and application. In this work, 10 wt% low-cost lignin was introduced into the PBAT to prepare composite films by melt blending and blow molding, and the POSS(epoxy)8 was selected as the compatibilizer to improve the compatibility of PBAT and lignin. The maximum tensile strength and the nominal strain at break subsequently increased by 48.2 % and 21.4 % respectively, while the water vapor permeability enhanced by 9.9 %. Furthermore, the UV aging resistance of PBAT/lignin films were significantly improved, with only 1 wt% POSS(epoxy)8 content. This work provides an efficient strategy to foster the end-user confidence in the low-cost and eco-friendly biodegradable polymer materials with efficient performance.

Biowaste-derived, nanohybrid-reinforced double-function slow-release fertilizer with metal-adsorptive function

Bio-based slow-release fertilizers (SRFs) have drawn significant attention in resolving food scarcity issues, improving nutrient utilization efficiencies, and preventing environmental pollution. However, current SRFs still need to improve their release profile, reduce the bioresource cost, and resolve multiple environmental issues e.g., different types of soil/water contamination. In this study, we propose an original concept to fabricate double-function and environmentally friendly SRFs with a controllable fertilizer release function and strong adsorption capability of trace metals in soils. The hypothesis is that a hydrophobic nanohybrid synthesized from the low-cost lignin biowaste and clay allows the well-dispersion in the bio-based polyurethane matrix derived from readily available agriculture byproducts. The exfoliation of nanohybrid in the biopolymer membrane not only blocks the path of hydrophobic fertilizer release but also possesses cationic ions absorption function. The results show that the nanohybrid has a strong metal adsorption capability and the synthesized nanohybrid-based controlled-release fertilizers (CRFs) exhibit excellent N release longevity (more than one month). These multiple-function CRFs promote plant growth in trace-metal contaminant soil in a cherry radish matrix study. This work also provides a detailed examination of the synthesis of lignin clay hybrid biocomposite, the encapsulation of fertilizers by the biocomposite membrane, the study of the nutrient release profile, and the metal adsorption mechanism. For the first time, biobased and low-cost CRFs provide multiple functions including controllable fertilizer release, strong metal adsorption capability for soil remediation, or trace metal re-utilization, which is expected to open a new door for large-scale utilization of CRFs in a nutrient contaminant soil environment.

Synthesis of oxygen/nitrogen/sulfur codoped hierarchical porous carbon from enzymatically hydrolyzed lignin for high-performance supercapacitors

Heteroatom codoped porous carbon materials derived from low cost lignin play an important function in the sustainable development of supercapacitors. Herein, enzymatically hydrolyzed lignin (EHL) aminated through Mannich reaction was processed using a facile carbonization activation route to synthesize three-dimensional O/N/S codoped hierarchical porous carbon (ONS-HPC), in which KOH was the activation agent. The EHL-derived carbon materials possessed high specific surface area, abundant porous structure, and multi-heteroatoms with high doping density. Given the above synergistic effect, the ONS-HPC electrode exhibited a superior specific capacitance of 318 F g−1 at 0.5 A g−1 and excellent rate capability of 62% capacity retention at 50 A g−1. The fabricated asymmetric supercapacitor device based on the ONS-HPC delivered a remarkable energy density of 16.7 W h kg−1 with the power density of 249 W kg−1 and ultralong cycle-lifetime with 99.58% capacitance retention after 10,000 cycles. This result suggests the successful conversion of economical natural lignin to sustainable high-performance porous carbon electrode for supercapacitor via a facile and low-cost synthetic strategy.

Recyclable & highly porous organo-aerogel adsorbents from biowaste for organic contaminants' removal

Selective aerogel has become an attractive adsorbent for removing oil and organic contaminants due to its low density and excellent adsorption capacity. However, aerogels usually use non-sustainable or expensive nanomaterials and require complicated fabrication processes. Herein, using low-cost lignin reclaimed from the biorefinery waste stream as the starting material, we fabricated a highly porous, mechanically strong, and stable aerogel via a simple and one-step method under mild conditions. This aerogel exhibits a controllable micropore structure and achieves quick and efficient adsorption for oil (435% g/g), as well as toxic solvents such as THF (365% g/g). The selective and stable adsorbent can be reused multiple times and the oil adsorption capacity after 5 cycles remained at 89%. This highly efficient, mechanically strong, stable, and regenerable aerogel is a potential candidate for multiple applications such as cleaning up organic contaminants, oil remediation, and oil/water separation. Meanwhile, it also employs a “waste-treat-waste” concept by adding extra value to the biorefinery process for high-efficiency circular bioeconomy.

Lignin-based carbon nanofibe rs: Morphologies, properties, and features as substrates for pseudocapacitor electrodes

In this work, lignin-based carbon nanofibers (LCNFs) were for the first time served as substrate for in-situ electrodeposition of polyaniline (PANI) and tested as pseudocapacitor. Two LCNFs with different lignin ratios were designed to distinguish their morphology and structural properties. Next, PANI deposition mechanisms on both LCNFs were investigated and the electrochemical performance of the resulting LCNF/PANIs were evaluated. It was found although LCNF2 was composed of less uniform nanofibers due to more presence of lignin in precursor dope, it had higher tensile strength/modulus than LCNF1 (strength: 34.3MPa to 24.2 MPa; Modulus: 2.40 GPa to 1.45GPa) and was more cost-effective. Particularly, the beaded fibers on LCNF2 contributes to the deposition of PANI with higher specific mass capacitance (612.8 F g−1 to 547.0 F g−1). Upon assembling into solid-state supercapacitors, the Cm of LCNF2/PANI device was determined to be 229 F g−1 and the maximum energy density was 11.13Wh kg−1 at a power density of 0.08 kW kg−1. This work showed LCNF produced from renewable and low-cost lignin could be directly used as substrate for PANI deposition. Moreover, the composition in spinning dope played an important role in determining the performances of resulting pseudocapacitors.

Dual-templated synthesis of mesoporous lignin-derived honeycomb-like porous carbon/SiO2 composites for high-performance Li-ion battery

Lignin-derived carbon is regarded as one of the most promising electrochemical energy storage materials because of its sustainability, low cost and high conductivity. However, the lithium-ion storage capability of lignin-derived carbon in lithium-ion batteries (LIBs) is hampered by its disordered wine bottle-like micropores. Herein, a lignin-derived honeycomb-like porous carbon encapsulated SiO 2 (LHC/SiO 2 -21) with three-dimensional interconnected honeycomb-like mesoporous structure is synthesized via a dual-template-assisted self-assembly strategy. The ordered mesoporous structure and high pore volume (2.23 cm 3 g −1 ) synergistically lead to fast lithium ions diffusion kinetics and more lithium-ion storage sites. When applied as anode materials for LIBs, LHC/SiO 2 -21 exhibits a high reversible capacity of 1109 mAh g −1 , superior rate capability, and long cycle performance. Moreover, the high-capacity LHC/SiO 2 -21 is prepared by a green approach originating from low-cost lignin and self-assembly method. Thus, lignin-derived carbon materials have the great potential for the application in energy storage. Synopsis: A high-efficient and green process was developed to synthesis 3D lignin-derived honeycomb-like carbon/silica composite to buffer the volume expansion of silica and improve the dispersion of nano-SiO 2 . • HLC/SiO 2 -21 with 3D honeycomb-like structure is synthesized by a dual-templated method. • HLC/SiO 2 -21 has mesoporous pore size and large mesoporous pore volume. • SDBS used as soft template controls lignin microstructure and disperses nano-SiO 2 . • Nano-SiO 2 used as hard template provides uniform size of mesopores. • HLC/SiO 2 -21 anode shows excellent electrochemical performance.

Lignin-derived 3D porous graphene on carbon cloth for flexible supercapacitors.

In this work, we reported a new method to fabricate flexible carbon-based supercapacitor electrodes derived from a commercialized and low-cost lignin. The fabrication process skips traditional stabilization/carbonization/activation for lignin-based carbon production. Also, the process reported here was green and facile, with minimum solvent use and no pretreatment required. Characterization of the lignin showed that it has common properties among all types of lignin. The lignin was impregnated on carbon cloth and then subjected to direct laser writing to form the desired electrodes (LLC). The results showed that lignin was successfully bonded to carbon cloth. The LLC has a good porous carbon structure with a high IG/ID ratio of 1.39, and a small interlayer spacing d002 of 0.3436 nm, which are superior to most of the reported lignin-based carbons. Although not optimized, the fabricated LLC showed good supercapacitance behavior with an areal capacitance of 157.3 mF cm−2 at 0.1 mA cm−2. In addition, the superior flexibility of LLC makes it a promising electrode that can be used more widely in portable devices. Conceptually, this method can be generalized to all types of lignin and can define intriguing new research interests towards lignin applications.

Lignin–Clay Nanohybrid Biocomposite-Based Double-Layer Coating Materials for Controllable-Release Fertilizer

Bio-based slow-release fertilizers (SRFs) have drawn significant attention because their applications for crop production can improve nutrient utilization efficiency as well as prevent environmental pollution. However, current commercial SRFs still exhibit uncontrollable release patterns, use a large quantity of synthetic coating materials, and are unable to adapt to complex soil conditions (e.g., arid soil). In this study, a double-layer SRF was formulated from a low-cost lignin–clay nanohybrid composite to not only achieve controllable and slow nitrogen fertilizer release but also improve the water-holding property. The low-cost and hydrophobic lignin–clay nanohybrid was cross-linked with bio-based alginate to prepare the core-layer material, followed by a coating process using a highly water-absorbent polymer poly(acrylic acid) (PAA) to achieve a double-layer SRF. We examined the chemical structures, urea release rates, and water-holding capacities of the double-layer PAA–lignin–clay nanohybrid composite coated SRF (PLC-SRF). The results showed that PLC-SRF released 13–40% less urea and absorbed 23% more water than SRFs coated with only alginate. Its urea release rate is slower than that of previously reported SRFs using other materials. This nanocomposite coating material has great potential for producing a new type of bio-based SRFs that are beneficial to sustainable crop production.

Strong, Reusable, and Self-Healing Lignin-Containing Polyurea Adhesives.

Reusable, self-healable, removable, and strong bio-based polyurea adhesives were successfully synthesized via partially substituting polyetheramine with polyetheramine-grafted lignin and introducing a chain extender containing dynamic disulfide bonds. The polyetheramine-grafted lignin endowed the polyurea adhesives with significantly enhanced adhesion strength on either metal or wood substrates by introducing intensive hydrogen bonding interactions; the dynamic disulfide bonds played a key role in the excellent self-healing and reusable performance. The thermostability of polyurea adhesives was also improved by introducing lignin. This work provides a novel approach for the high-value utilization of low-cost lignin in recyclable adhesives with excellent comprehensive performance.

In-situ growth of graphene on carbon nanofiber from lignin

Design and synthesis of heterostructured carbon nanofibers is significant for applications in the field of optoelectronics, conductors and catalytic devices. Although lignin has been widely used as building blocks for fabricating nanofibers, it is still very challenging to synthesize conducting heterostructured carbon nanofibers without using additional catalysts. Herein, we first in-situ grew graphene grafted carbon nanofibers (G/CNFs) using calcium lignin sulfonate as starting materials without addition of catalysts. Through the electrospinning, pyrolysis and washing procedure, the as-spun nanofibers are converted into the flexible G/CNFs films. The in-situ formed CaS nanoparticles serve as catalysts for the growth of graphene on the surface of the CNFs, when the carbonization temperature is over 1100 °C. The as-prepared G/CNFs films exhibit superior electronic conductivity of 2377.9 S m−1, which is comparable to the values reported in the literature. As a proof-of-concept, the as-fabricated lithium-sulfur battery exhibits a high discharge of 808.7 mAh·g−1 after 600 cycles at 0.2 C by using the G/CNFs membrane as stand-alone and flexible sulfur cathode scaffolds. This work represents a promising new approach for designing heterostructured graphene/CNFs using low-cost lignin precursors, and provides significant insights for the sustainable development of CNFs in numerous applications.

Iron nanoparticles encapsulated within nitrogen and sulfur co-doped magnetic porous carbon as an efficient peroxymonosulfate activator to degrade 1-naphthol

A novel iron nanoparticles encapsulated within nitrogen and sulfur co-doped magnetic porous carbon (Fe-N-S-MPC) was proposed by one-pot pyrolysis strategy to activate peroxymonosulfate (PMS) to degrade 1-naphthol using low-cost lignin as precursors. The Fe-N-S-MPC was characterized for structure and properties by different characterizations. The obtained materials had the morphology of iron nanoparticles encapsulated within nitrogen and sulfur co-doped magnetic porous carbon with rich functional groups and large specific surface area, which made the materials have a good catalytic property. It was proved that the doping of nitrogen and sulfur is pivotal for improving the catalytic performance. The radical quenching experiment confirmed that sulfate radical (SO4−) and hydroxyl radical (OH) are two major reactive oxygen groups. The reaction had phenomenon of the free radicals upsurge in the early stage and the shortage in the later stage. Therefore, a mathematical model was put forward to represent the two-stage reaction kinetics. By adding oxidants in batches, the degradation effect could reach nearly 100% within 30 min. The Fe-N-S-MPC were applied to the degradation of 1-naphthol in soil and showed high degradation performance. This work provided a new type of catalytic material by the high-value utilization of waste for the degradation of organic pollutants.

Poly(ε-caprolactone) chains grafted from lignin, hydroxymethylated lignin and silica/lignin hybrid macroinitiators: Synthesis and characterization of lignin- based thermoplastic copolymers

Lignin is the second most abundant biopolymer after cellulose. Due to its biodegradability and availability, lignin is a suitable replacement for the conventional polyol. Modification of lignin enhances its reactivity and dispersion in the polymer- based materials in order to prepare low cost lignin- based thermoplastics as an alternative for petroleum- based thermoplastics. In this study, unmodified lignin and lignin modified with silica particles and formaldehyde were used as a polyol macroinitiator for ring opening polymerization (ROP) of ε-caprolactone (CL) monomer. As a determining parameter of the polymer chain length, the molar ratio of CL to hydroxyl groups (OH) of macroinitiator was set at 5.5 or 22 for all copolymers. Decrease in the OH peak intensity and the enhancement of carbonyl peak intensity were observed in the FTIR spectra, indicating progress of the reaction between lignin or modified lignins and CL. Compared to the macroinitiators, changes in the morphology of the graft copolymers were identified by SEM. The chain structure, chain length of the grafted polycaprolactone (PCL) onto the lignin or modified lignin and percentage of the free PCL were determined using NMR analyses. Thermal properties of the synthesized lignin- based thermoplastics were investigated by DSC and TGA analyses. By decreasing the CL/OH ratio from 22 to 5.5, melt temperatures (Tm) and degree of crystallinity (Xc) descended from 57 °C and 70% to 55 °C and 57%, respectively.

Lignin Nanosphere-Supported Cuprous Oxide as an Efficient Catalyst for Huisgen [3+2] Cycloadditions under Relatively Mild Conditions.

In this work, low-cost lignin nanospheres were fabricated and further applied as an efficient and sustainable support for preparing cuprous oxide (Cu2O) “green” catalyst by using electrospraying technology. The unalloyed lignin, a special three-dimensional molecular structure, was successfully processed into uniform nanospheres under an electrospraying condition. The synthesized lignin-supported Cu2O catalyst had a well-defined nanosphere structure, and Cu2O nanoparticles with sizes less than 30 nm were supported by exposed layers of lignin nanospheres. There were C–O–Cu bonds formed between the lignin nanospheres and the metallic nanoparticles. The lignin nanospheres and the lignin nanosphere-supported catalyst werfe characterized by utilizing XRD, SEM, TEM, XPS, EDS, and TGA. The immobilization of Cu2O nanoparticles on the lignin nanospheres was beneficial for dispersion of the Cu2O nanoparticles and preventing their aggregation, which could cause catalyst deactivation, which favored the Huisgen [3+2] cycloaddition reaction. The triazole synthesis results indicated that the lignin nanosphere-supported Cu2O catalyst had a high catalytic performance with 99% yield under solvent-free conditions. Furthermore, the as-synthesized catalyst could be recycled for four times without significantly losing its catalytic activity.

Removal of lead ion and oil droplet from aqueous solution by lignin-grafted carbon nanotubes

Water contamination is one of the most serious problems afflicting people throughout the world, innovation of nanomaterials with eco-friendliness is important for a greener environment. Here, an eco-friendly nanocomposite based on lignin grafted carbon nanotubes (L-CNTs) is reported as a new type of adsorbent for water remediation. By integrating the tridimensional structure, oxygen-containing functional groups and eco-friendliness of lignin with the high surface area and mechanical stability of CNTs, the as-prepared nanocomposite not only possesses a good water-dispersibility and eco-friendliness, but also exhibits an excellent adsorption capability for lead ion and oil droplet. It shows a high distribution coefficient for lead ion (Kd=3.6×105mL/g) that is comparable to some benchmark materials, including mesoporous carbon and metal-organic frameworks. The large surface area and tridimensional structure also endows L-CNTs with a high removal efficiency for oil droplet from water. Moreover, the cost of the nanocomposite has been minimized by incorporation of the low cost lignin. These results demonstrate the as-obtained nanocomposite with a natural polymer layer has advanced adsorption capability, low-in cost and eco-friendliness, and accordingly is an ideal candidate for water cleanup.