Electrospray lignin nanoparticles as Pickering emulsions stabilizers with antioxidant activity, UV barrier properties and biological safety.

The inherent complexity and large particle size of native-state lignin are the major factors limiting its performance in high value-added materials. To realize the high-value application of lignin, nanotechnology is a promising method. Therefore, we offer a nanomanufacturing approach to produce lignin nanoparticles with uniform size, regular shape and high yield using electrospray. They are efficient in stabilizing oil-in-water (O/W) Pickering emulsions that remain for one month. Lignin has the abilities to demonstrate broad-spectrum UV resistance and green antioxidant properties in advanced materials, taking advantage of its inherent chemical characteristics. In addition, lignin has high safety for topical products according to an in vitro cytotoxicity test. In addition, the nanoparticle concentrations used in the emulsion were as low as 0.1 mg/ml, which maintained UV-resistant ability and overcame traditional lignin-based materials with unfavorable dark colors. Overall, lignin nanoparticles not only act as stabilizers at the water-oil interface but also realize the high functionality of lignin.

Preparation of biomass-based gas separation membranes from biochar residue obtained by depolymerization of lignin with ZSM-5 to promote a circular bioeconomy.

Reuse of biochar residues after lignin degradation will not only save costs but also reduce the pollution, protect and improve the environment. In this study, biochar residue (BR) after peanut shell lignin selective depolymerization on ZSM-5 were recycled, and characterized by Scanning Electron Microscopy, Surface area & pore size distribution analyzers, Thermogravimetric Analysis. Subsequently, a series of hybrid matrix membranes were prepared using ethyl cellulose as the matrix and biochar residue after depolymerization under different reaction conditions as the filler. The separation performance of BR/EC membranes for CO2/CH4 mixed gas and CO2/N2 mixed gas was measured. The results showed that the gas separation membranes prepared with biochar residue (3 h, 300 °C) as filler had good gas separation characteristics. The resulting mixed-matrix membrane exhibited a permeability of 66.00 Barrer for CO2 and selectivities of 9.97 for CO2/CH4. Meanwhile, the resulting mixed-matrix membrane exhibited a permeability of 79.53 Barrer for CO2 and selectivities of 20.01 for CO2/N2. Both exceed the upper limit of known pure EC membranes. Therefore, the use of biochar residue after ZSM-5 depolymerization as a filler for gas separation membranes is a feasible way. Furthermore, the membrane is well stabilized, proving its good potential for industrial applications.

Lignin-based electrospinning nanofibers for reversible iodine capture and potential applications.

The capture of radioactive iodine has recently attracted much attention due to the release of radioactive iodine during nuclear waste disposal and disasters. Exploring highly efficient, sustainable, and eco-friendly materials for capturing radioactive iodine has great significance in developing safe nuclear energy. We reported highly efficient, natural, lignin-based, electrospun nanofibers (LNFs) for reversible radioiodine capture. Abundant iodine adsorption sites, such as functional groups and the interaction between the intermolecular forces exist in LNFs. The capacity of the LNFs for the saturated adsorption of iodine was found to be 220 mg·g-1, which is higher than that of the majority of bio-based adsorbents studied. Moreover, the LNFs exhibited an excellent recycling behavior, and their absorption capacity remained at 84.72% after 10 recycles. Therefore, the results imply that the lignin-based nanofibers can act as a natural, sustainable and eco-friendly packed material for the purification columns in industrial applications. The results demonstrate that the novel, nanostructured, natural biomass, as an ideal candidate has the potential for practical nuclear wastewater purification.

Characterization of lignin extracted from Acanthopanax senticosus residue using different methods on UV-resistant behavior.

Acanthopanax senticosus has been used to extract active products. However, abundant Acanthopanax senticosus residues (ASR), which contain plenty of lignin are discarded after extraction. An appropriate extraction method should be chosen to obtain the lignin with such desirable properties. Thus, this study investigated the effect of alkali, milled wood, deep eutectic solvent and ethanol methods on the lignin. Lignin obtained from different extraction methods were characterized, yields, chemical structure, thermal behavior, molecular weight and phenolic content were evaluated. The results show that the process of lignin acquisition has a great influence on the properties of lignin. Moreover, the multifarious functional groups exist in lignin macromolecules, such as phenolic, ether groups and other chromophores, conferred good UV resistance to lignin. Among them, the lignin from alkali method has the most phenolic-OH groups and smallest molecular weight result in a good UV-resistant, the SPF value achieves 2.39 at 1% AL content, the alkali method was the best way to make sunscreen blended with cream take various factors into consideration. This study used lignin as a bioactive ingredient to provide UV-resistant property to sunscreen formulations. Furthermore, lignin extracted from Acanthopanax senticosus residue provides a new application for the treatment of herb residue waste.

Unlocking the response of lignin structure by depolymerization process improved lignin-based carbon nanofibers preparation and mechanical strength.

We reported a new approach for development of lignin-based carbon nanofibers (LCNFs) from two lignin-derived bio-oil (LB) obtained from catalytic depolymerization reaction combined with the organic solvent gradient separation process (including ethanol-soluble LB (EL) and tetrahydrofuran-soluble LB (TL)). This approach was particularly unique and translatable as it uses small molecule TL with high reactivity and low heterogeneity obtained via stalk lignin depolymerization to produce good morphologies and mechanical performances of LCNFs mixed with polyacrylonitrile under 85% high replacement rates. We first detailed characterization studies such as 2D-HSQC NMR, 31P NMR, FT-IR, GPC, TGA and DSC were conducted to understand the properties of EL and TL. Then, the goal of the influence of EL and TL on the LCNFs morphologies and mechanical properties were accomplished by using SEM, XRD, Raman and material testing machine. As compared with EL, the TL had excellent linear structure with relatively less total phenolic-OH groups and heterogeneity, which could improve lignin structure with better alignment along PAN, and thus increased the lignin replacement rates and mechanical performances of LCNFs.

Efficient and controllable ultrasound-assisted depolymerization of organosolv lignin catalyzed to liquid fuels by MCM-41 supported phosphotungstic acid.

In this study, effects of catalyst types, reaction temperatures, reaction times, reaction solvents and ultrasound frequencies were carefully investigated to improve the yields and characteristics of various depolymerization products of organosolv lignin. Generally, both catalyst types and ultrasound frequencies played important roles in promoting lignin depolymerization and reducing char yield. In particular, the yield and distribution of phenolic monomer (PM) products were greatly influenced by pore structure and acidity of the catalyst. The optimal reaction condition was got in isopropanol at 310 °C for 6 h with 30% ultrasound frequency and 50% phosphotungstic acid (PTA)/MCM-41 catalyst. The highest yields of PM, bio-oil, liquid fuels and lignin conversion were reached as 8.63 wt%, 86.89 wt%, 95.52 wt% and 98.54 wt%, respectively. The results showed that ultrasound acoustic cavitation could enhance the depolymerization of lignin, thus greatly enhancing production of liquid fuels. Simultaneously, the hydrogen composition and high heating value of various lignin depolymerization products improved, and the oxygen content decreased, indicating that hydrogenation and/or hydrodeoxygenation happened during the depolymerization process. Finally, we also found that the 50% PTA/MCM-41 catalyst had high stability; it could be reused for up to five cycles without loss of catalytic activity.