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In the past 70 years, over 8 billion tons of plastics have been produced, the majority of which cannot be fully biodegraded, causing their fragments to be found everywhere in the biosphere, including living organisms. Herein, a group of biodegradable composites were produced by blending poly(butylene adipate-co-terephthalate) (PBAT) with technical lignin through a twin-screw extrusion method. Two strategies were developed to improve the mechanical properties of PBAT/lignin composites: (1) modifying lignin via methylation to reduce hydrogen bonding between −OH groups and (2) enhancing the intermolecular interactions between PBAT and lignin by adding maleic anhydride-graft-PBAT as a compatibilizer. The composites obtained from the two strategies with 60 wt % lignin contents exhibited ideal tensile performance which could meet the requirement of the Chinese National Standard for packaging. The interactions between different composite components were investigated by morphological and thermal analyses. The results showed that when lignin is used as filler in the composites, the molecular mobility of lignin and the size of its agglomerates remarkably impacted the ductility and mechanical strength of the PBAT/lignin films. A simple cost comparison between neat PBAT film and PBAT/lignin composite films indicated that the latter was economically competitive, and the production costs could significantly reduce by 36%.

The present chemical converted graphene sheets are mostly dependent on the exfoliation of graphite with strong oxidants, which suffer from heavy burden of environmental pollution. Here, we report a simple, green and scalable method to synthesize graphene sheets by one-pot activation-synthesis method derived from black liquor, a biomass waste resource in pulping industry. The pulping black liquor consisting of alkali lignin as main components with phenyl skeletons and condensed aromatic segments was successively transferred from heterogeneous chemical states into micron-sized graphene sheets. The proposed conversion mechanism mainly consists of aromatic rebonding, refusion and deoxygenation reaction, in which alkaline species acting as situ-activation agent. The graphene sheets obtained from pulping black liquor (BL-G) show typical hexagonal honeycomb lattice in thickness of 1–3 atomic carbon layers with controllable lateral size ranging from 0.36 to 2.5 μm. After spin-coating single- or few-layer of BL-G sheets onto flexible substrate, it could produce transparent and conductive thin films (TCFs) with sheet resistance as low as 2.1 kΩ sq−1 and 85% transmittance for 550 nm light, suggesting its great potentials using as flexible electrode materials. This green synthesis route may pave a bright way in large-scale production of chemically converted graphene sheets.

To maximize the utilization of Abaca lignin in the current biorefinery, structural characteristics of native lignin from Abaca were firstly comprehensively investigated. Parallelly, effective delignification of Abaca was achieved by alkaline hydrogen peroxide (AHP) process, which facilitated the production of specialty paper in industry. The structural changes of lignin macromolecules during the AHP delignification were illustrated by comparing the structural differences of the released lignin fraction and corresponding native lignin, which were analyzed via the advanced analytical methods, such as 2D-HSQC NMR, 31P NMR, pyrolysis-GC/MS, and GPC techniques. It was found that Abaca lignin is a HGS-type lignin, which is overwhelmingly composed of β-O-4 linkages and abundant hydroxycinnamic acids (mainly p-coumaric acid). In addition, partial cleavage of β-O-4 linkages and p-coumarate in lignin occurred during the AHP delignification process. Meanwhile, AHP process also led to the elevation of H-type lignin units in AHPL. Considering that β-O-4 bond is vulnerable in the catalytic degradation process of lignin, the lignin with abundant β-O-4 linkages is beneficial to the downstream conversion of lignin into aromatic chemicals.

Making full use of the lignocellulose is of great significance to the current biorefinery enterprises. As a natural macromolecule polymer, lignin has a prominent potential as renewable feedstock to...

Efficient deconstruction of lignocellulose is vitally important for the biorefinery industry because lignin structures play a crucial role in the high value-added conversion of lignin. In this study, an integrated process based on hydrothermal pretreatment (HTP) and Kraft delignification was proposed to deconstruct lignocellulosic biomass. It was found that the HTP not only facilitated the production of xylo-oligosaccharides but also reduced the chemicals dosage of the following delignification. The structural characteristics of lignin obtained from the integrated process were investigated by NMR spectroscopy and gel-permeation chromatography. Additionally, double enzymatic lignins (DELs) isolated from different feedstocks were used as "model lignin" to delineate the structural transformations of lignin during H2 O2 , ClO2 , and O3 bleaching. Significant changes of the lignin structure were observed during the ClO2 bleaching process, including degradation of aromatic rings, enrichment in p-hydroxyphenyl units, and increase of carboxylic groups. A comparison of the structural characteristics of the bleached lignins indicated that HTP benefited the subsequent bleaching process. Enhanced knowledge of lignin chemistry during deconstruction and delignification could provide valuable insight into the current lignocellulose biorefinery.

In this study, the effect of traditional acidification and hydrothermal acid hydrolysis on the separation of lignin and xylose from the pre-hydrolysis liquor (PHL) of kraft pulping process was comparatively evaluated. The PHL was acidified at room temperature or hydrothermally treated under acidic conditions to isolate lignin and xylose. As compared with the lignin removal rate of 26.8–32.7% by traditional acidification method, a much higher lignin removal rate of 57.1% was achieved by hydrothermal acid hydrolysis. Meanwhile, the content of xylose in the PHL increased dramatically from 7.91 to 13.91–34.82 g/L after the hydrothermal acid hydrolysis. The hydrophilicity of the obtained lignin gradually increased as evidenced by the decrease of the corresponding water contact angel. Additionally, the thermal stability of the lignin sample increased steadily with the increment of acid dosage. The hydrothermal acid hydrolysis provides an effective approach to fractionate lignin and xylose from PHL.

To understand the structural features and transformations of hybrid Pennisetum (HP) lignin, an integrated treatment on the basis of microwave-assisted hydrothermal pretreatment (MHTP) (at 180–200 °...

Pre-hydrolysis liquor (PHL) from the kraft-based dissolving pulp process contains large amounts of hemicelluloses, which is usually treated as an effluent and further efforts have to be involved to eliminate the pollution disposal. However, the hemicelluloses-rich PHL is a promising candidate for the production of carbon microspheres via hydrothermal carbonization. The yield of the carbon microspheres directly derived from the hydrothermal carbonization of the hemicelluloses-rich PHL (22.1%) was almost twice than that from xylose (13.1%). Furthermore, sulfuric acid and the lignin in the PHL could significantly improve the yield and change the size of the carbon microspheres obtained from the PHL. Additionally, the activated carbon microspheres functionalized with acrylic acid showed improved adsorption capacities for Pb(II) ion (273.4 mg/g) and methylene blue (701.3 mg/g). The hydrothermal carbonization of the PHL not only utilizes the hemicelluloses in the PHL, but also reduces the pollution load of the PHL significantly.