Cellulose-based aerogels show great potential as absorbents for oil and chemical spill cleanup due to their low density and excellent absorption capacity. However, the hydrophility and inferior mechanical properties have often limited their practical applications. In this study, highperformance biomass-based aerogels were prepared by freeze-casting aqueous suspensions of polyvinyl alcohol and cellulose nanofibrils in the presence of hydrolyzed methyltrimethoxysilane sol. Successful silylation on the substrate surface was confirmed by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermal stability, and water contact angle measurements. Freeze-casting successfully assembled a highly aligned interconnected porous structure, resulting in the prepared aerogels with high modulus and strength in the aligned direction (along the freezing direction) and outstanding compression flexibility in the perpendicular direction (transverse to the freezing direction). The ultralow density (10.2 kg/m 3 ), high hydrophobicity (water contact angle of 140°), and good compressive recovery (84% recovery of its original thickness after 100th compression tests) allow the aerogel to absorb oils and organic solvents 45−99 times higher than its own weight. Meanwhile, good reusability was also observed with an absorption capacity greater than 84% after 35 absorption−squeezing cycles. The novel aerogels prepared in this study are expected to have great potential for application in treating oil and chemical spills.

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The aim of this study is to examine the wettability and thermal properties of individual bamboo fibers after alkali treatment. The individual bamboo fibers were treated by sodium hydroxide (NaOH) solution with varying concentrations (6, 8, 10, 15 and 25%) followed by freeze-drying treatment. The surface analysis of alkali-treated individual bamboo fibers was characterized by atomic force microscope. Water droplet on the individual fiber surface was observed with drop shaper analyzer and the contact angles on fiber surface were also measured. Thermal properties were further studied by thermogravimetric analysis. The results indicated that alkali treatment resulted in the increase in surface roughness of individual bamboo fibers. Alkali treatment with low NaOH concentration could enhance the wettability of treated individual bamboo fibers, and while the wettability was reduced with alkali treatment at high concentration (25%). Thermal analysis revealed that the onset of decomposition and the maximum decomposition were moved to higher temperature after alkali treatment at low NaOH concentrations (6, 8, and 10%), suggesting the improvement in the thermal stability of treated individual bamboo fibers, while the thermal stability was compromised after alkali treatment at higher concentrations (15 and 25%).