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Due to the similarity in chemical structure, lignin has presented great potential in the synthesis of bio-based phenolic resin. Herein, a facile and scalable synthesis strategy for a novel cage-like lignin-based phenolic resin was proposed through direct spray drying of the mixture of phenolic resin and unmodified lignin. The as-prepared lignin-based phenolic resin was pre-carbonized and carbonized using KOH to produce mesoporous carbon materials (LPRAC) that were further employed as supercapacitor electrodes. The results revealed that the lignin addition led to the noticeable change of the resin shape from perfect sphere to cage-like structure owing to the surfactivity and hydrophilicity of lignin. The cage-like structure promoted the KOH-activated pore generation and expansion in the carbonization process, resulting in the significantly increased specific surface area of the phenolic carbon and the intensified mesoporous formation. The electrochemical performance determination indicated that the specific capacitance of LPRAC-20% (20% lignin addition) was 217.3 F/g at 0.5 A/g, which was considerably higher than that of the lignin-free phenolic carbon (122.6 F/g). Moreover, the LPRAC-20% also exhibited preferable capacitance retention and excellent cycling stability. Accordingly, the present work offers a simple and scalable approach to prepare cage-like mesoporous carbon with excellent electrochemical performance from lignin-based phenolic resin and thus provides a promising route for lignin valorization in energy storage materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Carbon-supported Ru-based catalysts have shown great potential in the hydrodeoxygenation of biomass-derived chemicals but still suffer from the uneven/unstable metal loading owing to the weak affinity between the metal and the carbon-based support. Herein, novel ultrafine Ru nanoparticles supported on lignin-derived nitrogen-doped carbon layers (Ru/LNC) were prepared through a facile pyrolysis of lignin-Ru complex mixed with melamine and further subjected to the hydrodeoxygenation of levulinic acid (LA) into γ-valerolactone (GVL) using formic acid (FA) as the H-donor. The formation of lignin-Ru complexes and abundant N -anchoring sites collaboratively improve the dispersion of metals, thus forming the ultrafine Ru nanoparticles (∼3 nm). Meanwhile, the base site generated by nitrogen -doping promotes the adsorption of acidic reactants (FA and LA) to improve the catalytic performance. Therefore, Ru/LNC catalyst exhibited outstanding catalytic performance (99.5 % of LA conversion and 98.4 % of GVL yield), which was significantly higher than Ru/LC (without N doping) and Ru/C (fabricated through convention impregnation method). Owing to the strong interaction of N species and Ru nanoparticles, Ru/LNC also exhibited improved reusability. Consequently, this work proposes a novel route to fabricate ultrafine Ru nanoparticles embedded on lignin-derived nitrogen-doping carbon nanolayer and further demonstrates its superior applicability in LA hydrodeoxygenation. [ABSTRACT FROM AUTHOR]

As the most abundant aromatic biopolymer, lignin presents great potential to produce valuable materials and chemicals. However, its large-scale value-added application is still facing many practical challenges and one of them is the unstable properties caused by lignin heterogeneity. Herein, we developed a novel "one-step-three-fractions" fractionation strategy to reduce lignin heterogeneity using aqueous two-phase system (ATPS) composed of (NH 4) 2 SO 4 and ethanol. In contrast to conventional step-wise fractionation processes, the proposed process subdivided heterogeneous lignin into three homogeneous fractions in only one step: the first fraction (F1) dissolved in the ethanol-rich top layer; the second fraction (F2) dissolved in the salt-rich bottom layer and the last fraction (F3) insoluble in both two layers. F2 presented the lowest molecular weight followed by F1 while F3 showed the highest molecular weight. With the increase of molecular weight, the contents of guaiacyl unit and β-O-4 linkage increased while the content of hydrophilic groups (carboxyl and aromatic hydroxyl) decreased significantly. Moreover, the ATPS exhibited satisfactory recyclability and the fractionation approach could be applied to different types/sources of lignin. Consequently, the work indicates that ATPS is a novel and effective way to fractionate lignin and reduce its molecular weight polydispersity and structural heterogeneity in one step. [Display omitted] • Aqueous two-phase system (ATPS) consisting of (NH 4) 2 SO 4 and ethanol was used for lignin fractionation. • Enzymatic hydrolysis lignin was subdivided into three fractions in only one dissolution step. • The three fractions showed reduced heterogeneity in molecular weight and chemical structure. • The universal fractionation approach can be applied to different types/sources of lignin. • The fractionation using regenerated ATPS demonstrated the satisfactory recyclability. [ABSTRACT FROM AUTHOR]

• A double network physicochemical nanocomposite gel inhibitor was developed. • Chemical inhibitor was combined with double network gel by grafting reaction. • Functional group analysis proved excellent inhibition effects. • Physical, chemical and composite inhibition mechanism was analyzed. To strengthen the inhibition effect of an inhibitor on spontaneous coal combustion throughout the process, this study used solution polymerization to synthesize hyaluronic acid and polyethylene glycol into a double network gel. The double network gel was grafted with a chemical inhibitor, epigallocatechin gallate, and polymerized with nanomaterial attapulgite to prepare a double network gel composite inhibitor with a whole-process inhibition effect. From the results of the scanning electron microscopy test, we found that the folds and pores on the surface of the inhibitor considerably increased with composite treatment. From the results of thermogravimetric analysis, it was proved that the average increase in each characteristic temperature point of the coal sample was 28.15%. According to the results of differential scanning calorimetry, it was found that the heat release interval of the inhibited sample was narrowed, and the total heat release was reduced by 2408.08 J/g. From the results of gas analysis, it was concluded that the production of CO, CO 2 , and CH 4 by the inhibited sample markedly reduced, which verified the environmental friendliness of the inhibitor. Through a diffuse reflection infrared spectrum test, it was found that the inhibition treatment could deactivate the active groups in coal and increase the content of the ether bonds of the stable functional groups, which proved that the composite inhibitor is an excellent fire prevention material. [ABSTRACT FROM AUTHOR]

Over the recent years, the exploitation of antibacterial performance of lignin and its subsequent usage as bacteriostatic additives has gained increasing interests. However, due to the restriction from structural heterogeneity, the antibacterial activity of lignin is always modest and unstable (especially against Gram-negative bacteria). In this regard, we proposed a facile one-step ethanol fractionation process to decrease the heterogeneity of lignin and, therefore, improve its antibacterial activity. Two fractions (Fs and Fi, 95% ethanol soluble and insoluble fraction, respectively) were obtained from bamboo kraft lignin (BKL) and their antibacterial effectiveness was compared. The results showed that the antibacterial activity of Fs increased significantly compared to that of BKL. On the contrary, Fi barely exhibited inhibitory effect on the growth of two Gram-positive bacteria and even promoted the growth of two Gram-negative bacteria. The much lower phenolic-OH content in Fi was an important reason for the absence of antibacterial activity. Besides, the growth promotion of Gram-negative bacteria by Fi was possibly caused by the formation of insoluble carriers for bacteria growth due to the poor water-solubility of Fi. Accordingly, after the elimination of Fi, the one-step fractionation significantly enhanced the antibacterial activity of lignin against both Gram-positive and Gram-negative bacteria. • Bamboo kraft lignin was subdivided into Fs and Fi by one-step ethanol fractionation. • Fs showed enhanced antibacterial activity compared to bamboo kraft lignin. • Fi barely showed inhibition on bacteria growth, and even promoted bacterial growth. • The antibacterial activity differences between Fs and Fi were elucidated. • One-step ethanol fractionation of lignin is effective to improve antibacterial activity. [ABSTRACT FROM AUTHOR]

Abstract Valorization of lignin based on its biological activities is always suffering the restriction from lignin heterogeneity, including wide molecular weight distributions and variable functional group contents. In this work, organosolv ethanol lignin (OEL) from corn stalk was divided into four fractions by multiple organic solvent successive extraction and the anti-tyrosinase activities of four obtained fractions were compared to evaluate the effect of lignin heterogeneity on the anti-tyrosinase activity. The characterization revealed that the successive extraction realized the fractionation of the heterogeneous OEL into four relatively homogeneous parts with gradually increasing molecular weight and decreasing phenolic OH content. The enzymatic inhibition study showed that the four fractions exhibited obviously different anti-tyrosinase activities and the dichloromethane fraction had the highest tyrosinase inhibition rate (75.12%, 0.5 mg/mL), whose value was comparable to the positive control p -hydroxybenzaldehyde. Besides, the relationships between the anti-tyrosinase activity and the lignin properties (purity, molecular weight and phenolic OH) were discussed to elucidate the possible formation mechanism of differences among the four lignin fractions in anti-tyrosinase activity. Consequently, these results suggest that lignin heterogeneity has a significant effect on the tyrosinase inhibition rate, and lignin fractionation is an effective way to screen lignin fractions with high anti-tyrosinase activity. Graphical abstract Unlabelled Image Highlights • Four different fractions were obtained by successive extraction using three organic solvents. • F1 with the lowest molecular weight and the highest phenolic OH showed the highest activity. • Inhibition type and mechanism of lignin against tyrosinase were proposed. • Lignin fractionation is effective to screen lignin fractions with high anti-tyrosinase activity. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Novel magnetic lignin-based core-shell microspheres are fabricated for dye adsorption. • Microspheres are cured using emulsion polymerization at a moderate temperature. • Microspheres have much higher methylene blue adsorption capacity than other lignin-based sorbents. • Functional groups of lignosulfonate preserved after curing contribute to high adsorption capacity. • Microspheres exhibit excellent recycling using magnetic separation and acidic ethanol extraction. Abstract The application of green adsorbents from renewable biomass for dye wastewater treatment has received wide attention in recent years. In this work, novel lignin-based Fe 3 O 4 @lignosulfonate/phenolic core-shell microspheres were fabricated for the first time to remove cationic dyes from aqueous solutions. The emulsion polymerization using p -toluenesulfonic acid as a curing agent was employed to synthesize the microspheres at a moderate temperature. Detailed characterizations were conducted to provide a broad evaluation of the microspheres followed by batch experiments to analyze the methylene blue (as a model cationic dye) adsorption performance. Results showed that lignosulfonate/phenolic shell coated uniformly on the Fe 3 O 4 core to form a well-defined core-shell microsphere. Due to cross-linking by phenolic resin, the lignosulfonate coated on the microspheres is highly insoluble in aqueous solutions at a wide pH range, which is prerequisite for an effective dye adsorption from wastewater. The adsorption study showed that the endothermic adsorption process was completed in 40 min and the adsorption kinetics followed a pseudo-second-order model. The equilibrium data were consistent with the Langmuir equation and the maximum monolayer capacity was 283.6 mg/g, which was much higher than those of most lignins and lignin-rich biomass. After adsorption, the microspheres were recycled and a fast regeneration (<10 min) was achieved using ethanol as a methylene blue extraction solvent. Overall, these results indicate that the novel Fe 3 O 4 @lignosulfonate/phenolic microspheres offer a great potential for removing cationic dyes from wastewater in practical applications. [ABSTRACT FROM AUTHOR]

Antimony is being extensively investigated as anode material for sodium ion batteries (SIBs) due to its appropriate sodium insertion potentials, flat charge-discharge plateau and high sodium storage capacity. However, it suffers from unsatisfied cycling stability originated from the huge volume change during cycling. Herein, hollow NiSb spheres confined by three-dimensional interconnected carbon matrix (NiSb⊂3DCM) are prepared by a cross-linking reaction between Ni 2+ and alginate and a galvanic replacement reaction. Benefiting from its the hollow, porous structure and mechanical buffer provided by Ni and carbon coating, NiSb⊂3DCM electrode can deliver a stable capacity of 366 mAh g −1 with 94.3% capacity retention rate after 400 cycles operated at 1 A g −1 , which is the best cycling performance reported so far for Sb-based alloy anodes. [ABSTRACT FROM AUTHOR]

Sodium ion batteries (SIBs) have been considered as promising alternative to lithium ion batteries (LIBs) for large-scale energy storage. However, their inferior electrochemical performances, especially cyclability and rate capability become the major challenge for further development of SIBs. Herein, Sb/C composite prepared via an efficient and facile method with alginate as precursor has been evaluated as anode material for sodium ion batteries. This method shows unique role in formation of porous Sb/C composite, controlling the particle size and achieving excellent carbon coating. Such a composite demonstrates high specific capacity (423 mAh g −1 at 0.1 A g −1 ), good rate capability (226 mAh g −1 at 15 A g −1 ), and excellent cycle life (81.4% capacity retention for 200 cycles at 2 A g −1 ). The facile synthesis and superior electrochemical performance of the Sb/C composite render it a promising anode material for high-performance SIBs. Furthermore, our study shows a feasible and effective way to prepare transition metal (oxides) and porous carbon nanocomposite for SIBs. [ABSTRACT FROM AUTHOR]

The heterogeneity of lignin chemical structure and molecular weight results in the lignin inhomogeneous properties which also covers the antioxidant performance. In order to evaluate the effects of lignin heterogeneity on its antioxidant activity, four lignin fractions from enzymatic hydrolysis lignin were classified by sequential organic solvent extraction and further evaluated by DPPH (1,1-Diphenyl-2-Picrylhydrazyl) free radical scavenging capacity and reducing power analysis. The characterization including FTIR, 1 H NMR and GPC showed that the fractionation process could effectively separate lignin fractions with distinctly different molecular weight and weaken the heterogeneity of unfractionated lignin. The antioxidant performance comparison of lignin fractions indicated that the dichloromethane fraction (F1) with lowest molecular weight (4585 g/mol) and highest total phenolics content (246.13 mg GAE/g) exhibited the highest antioxidant activity whose value was close to commercial antioxidant BHT (butylated hydroxytoluene). Moreover, the relationship between the antioxidant activity and the structure of lignin was further discussed to elucidate the mechanism of antioxidant activity improvement of lignin fractionation. Consequently, this study suggested that the sequential extraction was an effective way to obtain relatively homogeneous enzymatic hydrolysis lignin fractions which showed the potential for the value-added antioxidant application. [ABSTRACT FROM AUTHOR]

Introduction Poly(lactic-co-glycolic acid) (PLGA) has been extensively explored in the tissue engineering field with good biocompatibility and biodegradability. PLGA microspheres' injectable potency makes it highly desirable in dentin-pulp complex regeneration. Therefore, we investigated the cell adhesion, proliferation, odontogenic differentiation, and matrix mineralization of human dental pulp cells (HDPCs) on a PLGA microsphere scaffold. We hypothesized that this scaffold might be suitable for dentin-pulp complex regeneration. Methods PLGA microsphere scaffolds were fabricated using the double-emulsion solvent extraction technique with or without type I collagen surface modification. HDPCs were isolated from freshly extracted premolar or third molar teeth with patients' informed consent and ethical approval. Fourth-passage HDPCs (1 × 10 5 cells/ml) were seeded onto surface-modified or -unmodified PLGA microspheres and cultured in vitro . Cell adhesion, proliferation, and alkaline phosphatase activity were evaluated at different time points. Odontogenic-related gene expression ( DMP1 , DSPP , COL1 , OPN , and OCN ) were analyzed using quantitative real-time polymerase chain reaction. After 8 weeks of culture, samples were observed under scanning electron microscopy. Results Surface modification using type I collagen significantly enhanced HDPC attachment to the PLGA microspheres and promoted cell spreading. Alkaline phosphatase activity and odontogenic-related gene expression of HDPCs cultured with PLGA microsphere scaffolds were enhanced significantly compared with HDPCs cultured without PLGA microsphere scaffolds. After 8 weeks of culture, HDPCs combined with PLGA microspheres formed 3-dimensional structures. Partial degradation of the scaffolds and matrix mineralization were also observed. Conclusions HDPCs can adhere to the PLGA microspheres, proliferate and differentiate into odontoblastlike cells, and form a 3-dimensional complex with matrix mineralization. This study may provide insight into the clinical dentin-pulp complex restoration with HDPCs and PLGA microsphere constructs. [ABSTRACT FROM AUTHOR]

• This research mainly studied a novel PAM/SA-Ca(OH) 2 composite inhibitor. • Inorganic nanoparticles are combined with polyacrylamide by intercalation method. • Functional group analysis proved excellent inhibition effects. • Physical, chemical and composite inhibition mechanism was analyzed. In order to overcome the short service life of existing inhibitors, the physical inhibitor polyacrylamide (PAM) and the nanomaterial silica aerogel powder (SA) were selected to intercalate a composite inhibitor. The product was a polymer-based composite (PAM/SA). Thereafter, PAM/SA was combined with the chemical inhibitor Ca(OH) 2 to form a polymer-based composite inhibitor. Scanning electron microscopy revealed a significant increase in the number of folds and pores on the surface of PAM/SA. Through differential scanning calorimetry, it can be concluded that the thermal stability of PAM/SA was improved, and its glass transition temperature increased from 159 °C to 197 °C. In a thermogravimetric analysis, all characteristic temperature points of the coal samples treated with a composite inhibitor were found to have increased as compared to those treated with a single inhibitor. The thermogravimetric analysis demonstrated that the optimal ratio of PAM/SA to Ca(OH) 2 was 1:1, and the activation energy of the treated coal sample increased from 326.74 KJ·mol−1 to 510.89 KJ·mol−1. Through infrared spectroscopy, it was found that inhibition treatment can reduce reactive groups, such as hydroxyl and aliphatic hydrocarbons, and increase stable structural ether bonds. The above results show that a polymer-based composite inhibitor prepared using the intercalation method can better inhibit the coal spontaneous combustion. [ABSTRACT FROM AUTHOR]

Highlights: [•] Steam explosion decreased carbohydrate content in alkali-extracted lignin solution. [•] Lignin liquor without purification was methylolated under optimized conditions. [•] Methylolated lignin liquor substituted 50% phenolic adhesive with approved properties. [•] FTIR indicated formaldehyde was incorporated to aromatic C5 of G unit by methylolation. [•] Phenolic substitution by lignin from steam-explosion-derived biorefinery is feasible. [ABSTRACT FROM AUTHOR]