Fabrication of N and S co-doped lignin-based porous carbon aerogels loaded with FeCo alloys and their application to oxygen evolution and reduction reactions in Zn-air batteries.

Zn-air batteries are a highly promising clean energy sustainable conversion technology, and the design of dual-function electrocatalysts with excellent activity and stability is crucial for their development. In this work, FeCo alloy loaded biomass-based N and S co-doped carbon aerogels (FeCo@NS-LCA) were fabricated from chitosan and lignosulfonate-metal chelates via liquid nitrogen pre-frozen synergistic high-temperature carbonization with application in electrocatalytic reactions. The abundant oxygen-containing functional groups on lignosulfonates have a chelating effect on metal ions, which can avoid the aggregation of metal nanoparticles during carbonation and catalysis, facilitating the construction of a nanoconfinement catalytic system with biomass carbon as the domain-limiting body and FeCo nanoparticles as the active sites. FeCo@NS-LCA exhibited catalytic activity (E1/2 = 0.87 V, JL = 5.7 mA cm-2) comparable to the commercial Pt/C in the oxygen reduction reaction (ORR), excellent resistance to methanol toxicity and stability. Meanwhile, the overpotential of oxygen evolution reaction (OER) was 324 mV, close to that of commercial RuO2 catalysts (351 mV). This study utilizes the coordination action of lignosulfonate to provide a novel and environmentally friendly method for the preparation of confined nano-catalysts and provides a new perspective for the high-value utilization of biomass resources.

Lignin-modified graphitic carbon nitride nanotubes for photocatalytic H2O2 production and degradation of brilliant black BN.

As a renewable aromatic compound with enormous production potential, lignin has various potential high-value utilization pathways, but the success achieved in the field of photocatalysis is limited. Herein, this work prepares a new type of photocatalyst by modifying Graphitic Carbon Nitride Nanotubes (CNT) with self-assembled lignin nanospheres for the photocatalytic production of H2O2 and the degradation of azo dyes. Under light conditions, lignin enhances the production of H2O2 through oxygen reduction and collaborates with carbon nitride tubes to generate O2- and 1O2. Furthermore, carbon nitride tubes form electron-rich regions with lignin, promoting the transfer of electrons from adsorbed aromatic pollutants to this region, thereby facilitating their degradation. The experimental results indicate that the addition of 5 % lignin significantly enhances the photocatalytic degradation efficiency of azo dyes, with a degradation rate 1.87 times higher than that of the original carbon nitride tubes. Furthermore, CNL also have excellent degradation ability to pollutants in actual wastewater. This study provides new insights and prospects for the high-value utilization of lignin, enabling it to be used as a photocatalytic co-catalyst to participate in the photocatalytic degradation of environmental pollutants.

Synergistic effects of hierarchical porous structures and ultra-high pyridine nitrogen doping enhance the oxygen reduction reaction electrocatalytic performance of metal-free laminated lignin-based carbon.

Construction of non-metallic biomass-carbon based catalysts for fuel cell air cathode applications has attracted great attention in recent years. In this work, a convenient and clean technique was developed to fabrication nitrogen-doped lignin-based hierarchical porous lamellar carbon (N-LHPC) via lignin as the carbon precursor, melamine/urea as the nitrogen source and ZnC2O4.2H2O as the chemical activator. The N-LHPC has a high specific surface area (491.5 m2 g-1) and macroporous/mesoporous/microporous structures. The nitrogen doping of N-LHPC can reach 16.37 wt%, with a high pyridinic nitrogen content of 41.39 at.%. N-LHPC exhibits a high half-wave potential (0.87 V) and a large limiting current density (5.75 mA cm-2) in 0.1 mol KOH media which is comparable to the commercial Pt/C catalysts. Furthermore, N-LHPC was assembled as air cathode catalyst for Zn-air batteries to evaluate its practical catalytic performance, and the power density was as high as 191 mW cm-2, which was superior to the 20 wt% Pt/C electrocatalyst. This research demonstrates that lignin is a promising carbon source for the fabrication of high catalytic activity and economical electrocatalysts for energy storage systems.

A lignin-derived N-doped carbon-supported iron-based nanocomposite as high-efficiency oxygen reduction reaction electrocatalyst.

Fuel cells are a promising renewable energy technology that depend heavily on noble metal Pt-based catalysts, particularly for the oxygen reduction reaction (ORR). The discovery of new, efficient non-precious metal ORR catalysts is critical for the continued development of cost-effective, high-performance fuel cells. The synthesized carbon material showed excellent electrocatalytic activity for the ORR, with half-wave potential (E1/2) and limiting current density (JL) of 0.88 V and 5.10 mA·cm-2 in alkaline electrolyte, respectively. The material has a Tafel slope of (65 mV dec-1), which is close to commercial Pt/C catalysts (60 mV dec-1). Moreover, the prepared materials exhibited excellent performance when assembled as cathodes for zinc-air batteries. The power density reached 110.02 mW cm-2 and the theoretical specific capacity was 801.21 mAh g-1, which was higher than that of the Pt/C catalyst (751.19 mAh g-1). In this study, with the assistance of Mg5(CO3)4(OH)2·4H2O, we introduce an innovative approach to synthesize advanced carbon materials, achieving precise control over the material's structure and properties. This research bridges a crucial gap in material science, with potential applications in renewable energy technologies, particularly in enhancing catalysts for fuel cells.

Continuous-Flow Microreactor Accelerates Molecular Collisions for Lignin Depolymerization to Phenolic Monomers and Oligomers.

Effective depolymerization of lignin is the most important step for its comprehensive utilization. So far, most of the studies on depolymerization of lignin focused on batch processing, whereas only a few studies relied on the microreactor. In this study, we developed a continuous-flow microreactor for depolymerization of lignin into monomeric and oligomeric compounds. The yields of monomers and oligomers can be adjusted by varying the temperature, pressure, residence time, NaOH dosage, and solvent. Under optimized conditions, the lignin conversion rate was 77.73 wt %, and the monomer yield was 13.26 wt %, with 77.81% being phenolic compounds. In addition, comparative characterizations on the raw lignin and products demonstrated that the oil products were mainly composed of phenolic tetramers and trimers, and the effective cleavage of the ß-O-4 linkage of S-type lignin was responsible for the high yield of 2,6-dimethoxyphenol. It indicated that raw lignin could be effectively depolymerized continuously using the continuous-flow microreactor, and it will be a new strategy for comprehensive utilization of lignin to produce fine-chemical intermediates.

Lignin-derived sulfonate base metal-free N, S co-doped carbon microspheres doped with different nitrogen sources as catalysts for oxygen reduction reactions.

The oxygen reduction reaction (ORR) is an important step in the widespread application of metal-air batteries, so it is necessary to study and develop low-cost and efficient metal-free carbon-based catalysts to catalyze the ORR reaction. Heteroatomic doping, especially N and S co-doped carbon materials, has received much focus as a promising ORR catalyst. Meanwhile, the lignin material has high carbon content, wide source, and low price, and has wide application prospects for the preparation of carbon material catalysts. Here we report a hydrothermal­carbonation preparation method for the synthesis of carbon microspheres by utilizing lignin derivatives as carbon precursors. And a variety of N, S co-doped carbon microsphere materials were prepared by adding different nitrogen sources (urea, melamine, NH4Cl) to the microspheres. The N, S co-doped carbon microspheres (NSCMS-MLSN) catalysts achieved with NH4Cl as the nitrogen source displayed superior RR catalytic activity with high half-wave potential (E1/2 = 0.83 V vs. RHE) and current density (JL = 4.78 mA cm-2). This work provides some references on the method of preparing carbon materials co-doped with N and S and the choice of nitrogen sources.

Lignin-based hydrophobic DESs extracts Sudan dyes from aqueous solution.

As a synthetic pigment, Sudan red is commonly used as a food additive and is harmful to the human kidney and can even cause cancer. In this work, we developed a one-step strategy to synthesize lignin-based hydrophobic deep eutectic solvents (LHDES), which were fabricated via methyltrioctylammonium chloride (TAC) as hydrogen bond acceptor and alkali lignin as hydrogen bond donor. LHDES with different mass ratios were synthesized and the mechanism of formation was determined by different characterization techniques. The synthetic LHDES was used as the extraction solvent to establish a vortex-assisted dispersion-liquid microextraction method for the determination of Sudan red dyes. The practicality of LHDES was evaluated by applying it to the detection of Sudan Red I in real water samples (seawater, river water) and duck blood in foodstuffs, and the obtained extraction rate reached up to 98.62 %. The method is simple and effective for the determination of Sudan Red in food.

Could ecological restoration reduce income inequality? An analysis of 290 Chinese prefecture-level cities.

Ecosystem degradation and the serious wealth gap caused by rapid economic development have become problems that cannot be neglected during the progress of pursuing sustainable development and reducing income inequality in China. To determine whether ecological restoration such as vegetation cover could affect the income gap, we used data for 290 prefecture-level cities in China from 2007 to 2018 and analyzed the effect of ecological restoration on income inequality in China. In addition, we chose the year 2012 as a boundary and performed heterogeneity analysis to permit a detailed comparison of the variation in the effect over time. We found that ecological restoration can reduce income inequality in general, but this effect was not statistically significant until 2012. However, due to some practical obstacles (e.g., employment opportunities, educational attainment, social discrimination), reducing income inequality through ecological restoration will be a time consuming process and requires constant effort from the Chinese government and local managers such as funding green industries, providing more targeted technical training for the poor and social services for the rural migrant workers.

Lignin-based nitrogen/sulfur dual-doped nanosheets decorated with Co1-xS nanoparticles as efficient bifunctional oxygen electrocatalysts.

The development of efficient, cost-effective, bifunctional cathode catalyst materials to replace precious metals is highly attractive for the fabrication of Zn-air battery. Here, the three-dimensional N and S co-doped carbon nanosheets loaded with cobalt sulfide nanoparticles (Co1-xS@SNFC) for bifunctional oxygen electrocatalysis were synthesized with Co(NO3)2·6H2O as the Co source, lignin as the carbon source, thiourea as the nitrogen/ sulfur source, and MgO as the template. The synergistic effect of multiple active sites gives the Co1-xS@SNFC fast electrochemical kinetic properties and excellent stability to oxygen reduction reactions (ORR) and oxygen evolution reactions (OER). The half-wave potential and overpotential of Co1-xS@SNFC were 0.84 mV and 306 mV, respectively, which is closed to commercial noble metal catalysts. In addition, Co1-xS@SNFC exhibited four-electron transfer characteristics and ultra-low tafel slope. Compared with commercial Pt/C, the Zn-air battery assembled from Co1-xS@SNFC exhibited a low voltage gap of polarization curve (0.75 V) between charging and discharge and high power density (207 mWcm-2) in alkaline electrolyte. This work developed a green and novel fabrication approach for the synthesis of bifunctional electrocatalyst and provides a new idea for high-value utilization of biomass.

A pH-responsive chiral mesoporous silica nanoparticles for delivery of doxorubicin in tumor-targeted therapy.

The purpose of this study was to develop a nano-drug delivery system with intelligent stimuli-responsive drug delivery in tumor microenvironment (TME). Based on chiral mesoporous silica nanoparticles (CMSN) with a chiral recognition function in our previous research, a pH-responsive CMSN (CS-CMSN) was successfully prepared by chemical modification of chitosan (CS), and the related physicochemical properties, drug release performance, potential anti-tumor effect, and biological safety were studied. The results showed that the CS-CMSN were successfully modified by CS. Moreover, CS-CMSN displayed superior encapsulation ability for doxorubicin (DOX) and exhibited controllable pH-responsive drug release properties. In particular, in a physiological environment (pH 7.4/6.5), CS shielded the nanopores, prevented DOX release, and minimized side effects on normal cells. Once the CS-CMSN was exposed to the TME (pH 5.0), the pH-sensitive moiety of CS was cleaved in an acidic environment, along with the rapid release of DOX. In vitro cell experiments further proved that DOX@CS-CMSN was more strongly taken up by 4T1 cells and could enhance the toxicity to 4T1 tumor cells as well as promote cell apoptosis. More importantly, CS-CMSN were shown to have good biosafety in vitro and in vivo. Overall, the delivery of DOX by CS-CMSN nanocarriers is a promising strategy for tumor-targeted therapy.

Stabilization of Pickering emulsions via synergistic interfacial interactions between cellulose nanofibrils and nanocrystals.

Nanocellulose is a promising stabilizer for industrial emulsions that offers the advantages of sustainability, biodegradability and nontoxicity. Emulsions prepared using cellulose nanofibrils (CNF) and nanocrystals (CNCs) in mildly acidic lithium bromide trihydrate (MALBTH) were characterized in this study. At fixed CNCs concentration (0.3 wt%), increasing the CNF content from 0 to 0.9 wt% clearly influenced the stability and microstructure of Pickering emulsions. The Oil droplets size decreased and stabilized with increasing CNF loading. This emulsification behavior was attributed to the irreversible adsorption of CNCs on the surface of the oil droplets and the formation of a dense CNF network in the aqueous phase, thereby improving the emulsion stability. The universal applicability of the proposed method was verified using cyclohexane and edible olive oil as oil phases. Overall, this study may provide a novel means of producing all-natural, low-oil, food-grade emulsions with adjustable stability.

In-situ synthesis silver nanoparticles in chitosan/Bletilla striata polysaccharide composited microneedles for infected and susceptible wound healing.

A novel antibacterial strategy is urgently required to develop for solving bacterial biofilm obstruction and bacterial drug resistance in the infected wound healing process. Herein, the Chitosan/Bletilla striata polysaccharide composited microneedles were prepared by chitosan, tannic acid, AgNO3 and Bletilla striata polysaccharide through step centrifugation. In our design system, the porous structure of microneedles gradually disappeared, and the mechanical properties were significantly improved after multiple fillings. Ag+ is reduced in-situ to silver nanoparticles by the abundant polyphenols of tannic acid, displaying antibacterial effects both in vitro and vivo, even for methicillin resistant Staphylococcus aureus. The addition of Bletilla striata polysaccharide increased the ability of piercing biofilm and promoted wound healing. The microneedles exhibited good biocompatibility and with function of piercing the bacterial biofilms, scavenging excessive free radicals, inhibiting inflammatory factors, and promoting wound healing. Therefore, the multifunctional composited microneedles show great potential to promote infected and susceptible wound healing.

Surface Gelatin-Coated ß-Mannanase-Immobilized Lignin for Delayed Release of ß-Mannanase to Remediate Guar-Based Fracturing Fluid Damage.

Herein, we developed an efficient and convenient method to address the problem of thickener decomposition in the low- permeability oilfield production process. It is crucial to design breakers that reduce viscosity by delaying thickener decomposition in appropriate environments. By using lignin in biomass as a substrate for ß-mannanase immobilization (MIL), we fabricated a gel breaker, surface gelatin-coated ß-mannanase-immobilized lignin (Ge@MIL). Through experiments and performance tests, we confirmed that the prepared Ge@MIL can release enzymes at a specific temperature, meanwhile having temperature-sensitive phase change properties and biodegradability. The results also show the tight tuning over the surface coating of Ge@MIL by a water-in-oil emulsion. Therefore, the prepared Ge@MIL has a promising application in the field of oil extraction as a green and efficient temperature-sensitive sustained-release capsule.

From liquid hot water pretreatment solution to lignin-based hydrophobic deep eutectic solvent for highly efficient extraction of Cr (VI).

Liquid hot water (LHW) pretreatment has been widely investigated attributed to its advantages, such as environmental friendliness, the potential application of dissolved hemicellulose, and no chemical addition. Expanding the portfolio of products that can be made from LHW pretreatment solutions will be critical to enabling a viable LHW-based economy. We provide a one-step method to separate and functionalize lignin from the LHW pretreatment solution. A hydrophobic deep eutectic solvent (hDES) was prepared by using methyltrioctylammonium chloride (MTAC) and the LHW pretreatment solution and directly applied to the extraction of Cr (VI) in an aqueous solution. In the process of forming hDES, the removal rate of liquid hot water lignin (LHWL) was reached 99%. The new LHW-hDES exhibited excellent extraction performance for Cr (VI), the extraction capacity was as high as 198.402 mg g-1, optimum extraction conditions at the mass of hDES 0.10 g, vortex time 90 s, room temperature, and natural pH. Notably, we have shown that the method of combining the separation and functionalization of lignin in the LHW pretreatment solution, which can provide a way of thinking for the application of the LHW pretreatment solution.

Magnesium lignosulfonate-derived N, S co-doped 3D flower-like hierarchically porous carbon as an advanced metal-free electrocatalyst towards oxygen reduction reaction.

The development of metal-free electrocatalytic materials that are economical, friendly to the environment, and efficiency towards the oxygen reduction reaction (ORR) is of significant interest. Hence, this paper synthesizes nitrogen and sulfur co-doped three-dimensional magnesium lignosulfonate (MLS-derived) flower-like hierarchical porous carbon (NSLPC) materials by a simple and green method. The synthesized NSLPC uses magnesium lignosulfonate as the sulfur source and carbon precursor, melamine as nitrogen source, MgO as hard template, and ZnCl2 as the activator. We also investigated the effect of the ratio of MgO to ZnCl2 on the catalyst performance. When the ratio of MgO to ZnCl2 is 10:0.5, NSLPC-1005 possesses the highest ORR activity with an enormous surface area (1752.54 m2 g-1), abundant active sites, and a hierarchical porous network structure. In alkaline media, NSLPC-1005 has an initial potential of 0.97 V, as well as an excellent half-potential of 0.86 V (vs. Hg/HgO), and an ultimate current density of 5.35 mA cm-2. It exhibits attractive ORR performance as well as outstanding cyclic stability that are comparable to commercial Pt/C electrocatalysts. This research developed an effective approach to synthesize metal-free carbon materials with high activity and long-term durability as electrocatalysts, which have a promising application in sustainable energy conversion technology.

Cellulose I nanocrystals (CNCs I) prepared in mildly acidic lithium bromide trihydrate (MALBTH) and their application for stabilizing Pickering emulsions.

This study proposed a sustainable method to prepare cellulose I nanocrystals (CNCs I) from microcrystalline cellulose (MCC) in a mildly acidic lithium bromide trihydrate (MALBTH) system, a concentrated (50 wt%) solution of LiBr in water with recyclable formic acid (FA). First, the MCC was treated in the MALBTH system to generate CNCs with a uniform size, yield higher than 68.49% and crystallinity of 84.02%. Then, the CNCs could application for stabilizing Pickering emulsions for at least 15 days. Furthermore, FA was easily recycled from the MALBTH system, and the yield of the CNCs produced from the hydrolysis of MCC by using the recycled FA was still higher than 60%. Finally, this study provided a sustainable and green production of CNCs. A low-cost and environmentally friendly pathway to recover FA from the MALLBTH system at a high yield was still realized.

Ethanol organosolv lignin from different agricultural residues: Toward basic structural units and antioxidant activity.

The growing interest in the substitution of synthetic food antioxidants by natural ones has fostered research on vegetable sources and the screening of raw materials for identifying new antioxidants. Special attention is focused on their extraction from inexpensive or residual sources from agricultural industries. Herein, the antioxidant activities of lignin obtained from 4 residual sources were investigated. The obtained lignin samples were characterized by different analytical techniques evaluating their chemical structure, phenolic content, thermal behavior and molecular weight. The antioxidant activity of the analyzed lignins was evaluated by the DPPH assay, the radical ABTS assay, and trivalent iron reduction method. It was found t that lignin antioxidants could scavenge free radicals and reduce oxidants. The high correlation between antioxidant capacity and its total phenol content indicated that phenolic hydroxyl groups were the main contributors to these lignins' antioxidant activity.

[Progress in application of Bletilla striata polysaccharide in novel drug delivery systems and biomaterials].

As the main active ingredient of the orchidaceous herb Bletilla striata, B. striata polysaccharide(BSP) has pharmacological activities such as promoting coagulation, anti-inflammation, anti-oxidation, promoting wound healing, anti-tumor, and immunomodulation, and is biodegradable and non-toxic. Additionally, it has the material properties of suspension thickening, film-forming adhesion, coating and solubilizing, targeting and slow releasing, effect-enhancing and toxicity-reducing, etc., playing the role of unification of medicines and excipients. Therefore, BSP has a wide application prospect in the fields of drug delivery system and trauma repair. This paper reviews the research progress of BSP application in new drug delivery systems and biomaterials based on the related li-terature in recent years, with the aim of providing reference for the further research and application of BSP.

Modular DNA Circuits for Point-of-Care Colorimetric Assay of Infectious Pathogens.

Accurate, specific, and inexpensive detection of multiple infectious pathogens simultaneously is a significant goal for human health and safety. Herein we present a rationally designed modular DNA circuit for point-of-care (POC) detection of a variety of infectious pathogens based on nucleic acid isothermal amplification technology and DNAzyme-mediated colorimetric readout. A modular DNA circuit was constructed with a fixed module and a flexible module and was rationally designed according to genetic targets. On this basis, the platform could detect multiple genetic targets corresponding to infectious pathogens simultaneously. Signal amplification properties of the DNA circuit and the peroxidase-like DNAzyme enable the detection limits to reach the picomolar level. By urea treatment and magnetic separation, the fixed module can be reused at least five times, which makes this assay more economical and environmentally friendly. The detection of genetic infectious pathogens should be accomplished in 2 h with naked-eye observation and may provide an efficient tool for POC analysis of multiple infectious pathogens, especially in resource-poor areas.

Development of the mussel-inspired pH-responsive hydrogel based on Bletilla striata polysaccharide with enhanced adhesiveness and antioxidant properties.

Recently, smart hydrogels have attracted much attention for their abilities to respond to subtle changes in external and internal stimuli. Also, natural polysaccharide-based biomaterials are more appealing for their biocompatibility and biodegradability. However, limitations owing to their complex compositions and mechanisms, cumbersome synthetic routes, and single function call for a simple and effective strategy to develop novel multifunctional smart hydrogels. Herein, this developed work was achieved based on Bletilla striata polysaccharide (BSP), a kind of natural glucomannan with diverse bioactivities and biocompatibility, we fabricated a low-cost multifunctional hydrogel by oxidizing the catechol groups of carboxymethylated BSP(CBSP)-dopamine(DA) conjugate with adhesion, antioxidant, and pH-responsive properties. In this hydrogel system, CBSP as the backbone material, was negatively charged and conferred the hydrogel with pH sensitivity. The presence of catechol groups greatly enhanced the tissue adhesion and antioxidant capacities of the hydrogel. Meanwhile, the highly porous structure of hydrogel allowed berberine to be encapsulated and released to exhibit excellent and long-lasting antibacterial activity. In summary, the adhesion, antioxidant, pH-sensitive, and antibacterial multifunctional hydrogel showed massive potential in the biomedical field.