Conductive hydrogels have shown great promise in the field of sustainable power sources due to their unique features of sufficient flexibility, durability, and functional diversification. However, time-and energy-consuming polymerization process and poor adaptability in extreme environments severely impede their practical application in such an emerging field. Herein, a facile and universal self-catalytic system (AL-Cu 2+ ) based on alkali lignin (AL) macromolecule has been designed to rapidly fabricate conductive and transparent organohydrogels in alkaline water-ethylene glycol (EG) binary solvent, which displays extreme environment applicability (-40 to 60 °C), eligible stretchability (≈800% elongation), and robust self-adhesion (≈31.4 kPa). Interestingly, the introduced EG accelerates the polymerization, endows extreme freezing/ drying resistance, and improves self-adhesion for the organohydrogels. The organohydrogel (water/EG = 2/3) that combines the above merits inspires the construction of triboelectric nanogenerator (O-TENG) for mechanical energy harvesting and converting regardless of low-or high-temperature environments. The generated electricity by the O-TENG can be used directly or stored to drive commercial electronics and installed on human joints for movement monitoring. This work sheds light on designing environmentresistant flexible TENGs based on multifunctional soft materials with fast gelation strategy, provoking more attention to sustainable high-value utilization of lignin for advanced applications.
To meet the huge market demand for carbon fibers (CFs), great efforts have been focused on developing low-cost and sustainable CFs with comparable properties. Lignin, a polyaromatic heteropolymer in nature,...
Background
Cocksfoot grass (Dactylis glomerata L.) with high biomass yield and rich cellulose can be used to produce bioethanol as fuel additive. In view of this, ultrasonic and hydrothermal pretreatments followed by successive alkali extractions were assembled into an integrated biorefinery process applied on cocksfoot grass to improve its enzymatic hydrolysis. In this work, the effects of ultrasonic and hydrothermal pretreatments followed by sequential alkali extractions on the enzymatic hydrolysis of cocksfoot grass were investigated. In addition, since large amount of hemicelluloses were released during the hydrothermal pretreatment and alkali extraction process, the yields, structural characteristics and differentials of water- and alkali-soluble hemicellulosic fractions isolated from different treatments were also comparatively explored.
Results
The integrated treatment significantly removed amorphous hemicelluloses and lignin, resulting in increased crystallinity of the treated residues. A maximum saccharification rate of 95.1% was obtained from the cellulose-rich substrate after the integrated treatment. In addition, the considerable hemicelluloses (31.4% water-soluble hemicelluloses and 53.4% alkali-soluble hemicelluloses) were isolated during the integrated treatment. The released water-soluble hemicellulosic fractions were found to be more branched as compared with the alkali-soluble hemicellulosic fractions and all hemicellulosic fractions were mixed polysaccharides mainly composed of branched xylans and β-glucans.
Conclusion
The combination of ultrasonic and hydrothermal pretreatments followed by successive alkali extractions can dramatically increase the enzymatic saccharification rate of the substrates and produce considerable amounts of hemicelluloses. Detailed information about the enzymatic hydrolysis rates of the treated substrates and the structural characteristics of the co-produced hemicelluloses will help the synergistic utilization of cellulose and hemicellulose in cocksfoot grass.
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