Aerogels based on cellulose nanofibrils (CNFs) have been of great interest as absorbents due to their high absorption capacity, low density, biodegradability, and large surface area. Hydrophobic aerogels have been designed to give excellent oil absorption tendency from water. Herein, we present an in situ method for CNF surface modification and hydrophobic aerogel preparation. Neither solvent exchange nor fluorine chemical is used in aerogel preparations. The as-prepared hydrophobic aerogels exhibit low density (23.2 mg/cm(-3)), high porosity (98.5%), good flexibility, and solvent-induced shape recovery property. Successful surface modification was confirmed through field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and water contact angle measurements. The hydrophobic aerogels show high absorption capacities for various oils, depending on liquid density, up to 47× their original weight but with low water uptake (<0.5 g/g aerogel).

Recent advancements in cellulosic aerogels have been extensive, but the lack of reproducible customization over the aerogel’s overall 3D structure has limited their ability to adapt to different application requirements. In this paper, high pressure homogenization and 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) modified cellulose nanofiber (T-CNF) was printed using direct-ink-write (DIW) into customizable 3D structures. After freeze-drying and cross-linking, highly deformable and shape recoverable T-CNF aerogel 3D structures were obtained. The 3D printed parts have a porosity of 98% and density of 26 mg/cm3. Due to their sustainability, biocompatibility, ultralight weight with high porosity, and deformability, the resultant aerogels have great potential for applications in thermal insulation, shock/vibration damping, and tissue engineering. In addition, the 3D printed T-CNF aerogels were templated to impart hydrophobicity and electromechanical properties. The resultant aerogels demonstrated potential for oil/water separation, and electronic related applications.

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Here, a new proton-exchange-membrane electrolysis is presented, in which lignin was used as the hydrogen source at the anode for hydrogen production. Either polyoxometalate (POM) or FeCl was used as the catalyst and charge-transfer agent at the anode. Over 90 % Faraday efficiency was achieved. In a thermal-insulation reactor, the heat energy could be maintained at a very low level for continuous operation. Compared to the best alkaline-water electrolysis reported in literature, the electrical-energy consumption could be 40 % lower with lignin electrolysis. At the anode, the Kraft lignin (KL) was oxidized to aromatic chemicals by POM or FeCl , and reduced POM or Fe ions were regenerated during the electrolysis. Structure analysis of the residual KL indicated a reduction of the amount of hydroxyl groups and the cleavage of ether bonds. The results suggest that POM- or FeCl -mediated electrolysis can significantly reduce the electrolysis energy consumption in hydrogen production and, simultaneously, depolymerize lignin to low-molecular-weight value-added aromatic chemicals.