Aerogels derived from nanocellulose have emerged as attractive absorbents for cleaning up oil spills and organic pollutants due to their lightweight, exceptional absorption capacity, and sustainability. However, the majority of the nanocellulose aerogels based on the bottom-up fabrication process still lack sufficient mechanical robustness because of their disordered architecture with randomly assembled cellulose nanofibrils, which is an obstacle to their practical application as oil absorbents. Herein, we report an effective strategy to create anisotropic cellulose-based wood sponges with a special spring-like lamellar structure directly from natural balsa wood. The selective removal of lignin and hemicelluloses via chemical treatment broke the thin cell walls of natural wood, leading to a lamellar structure with wave-like stacked layers upon freeze-drying. A subsequent silylation reaction allowed the growth of polysiloxane coatings on the skeleton surface. The resulting silylated wood sponge exhibited high mechanical compressibility (reversible compression of 60%) and elastic recovery (∼99% height retention after 100 cycles at 40% strain). The wood sponge showed excellent oil/water absorption selectivity with a high oil absorption capacity of 41 g g^–1. Moreover, the absorbed oils can be recovered by simple mechanical squeezing, and the porous sponge maintained a high oil-absorption capacity upon multiple squeezing-absorption cycles, displaying excellent recyclability. Taking advantage of the unidirectional liquid transport of the porous sponge, an oil-collecting device was successfully designed to continuously separate contaminants from water. Such an easy, low-cost, and scalable top-down approach holds great potential for developing effective and reusable oil absorbents for oil/water separation.

中文翻译：

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具有弹簧状层状结构的高压缩木材海绵作为有效和可重复使用的吸油剂

源自纳米纤维素的气凝胶由于其轻巧，出色的吸收能力和可持续性，已成为吸引人的吸收剂，用于清理溢油和有机污染物。然而，基于自下而上制造工艺的大多数纳米纤维素气凝胶仍然缺乏足够的机械强度，因为它们具有随机组装的纤维素纳米原纤维的无序结构，这阻碍了它们作为吸油剂的实际应用。在这里，我们报告了一种有效的策略，可以直接从天然轻木中制造出具有特殊的弹簧状层状结构的各向异性纤维素基木海绵。通过选择性去除木质素和半纤维素。化学处理破坏了天然木材的薄壁细胞壁，形成了层状结构，冷冻干燥后具有波浪状的堆叠层。随后的甲硅烷基化反应使聚硅氧烷涂层在骨架表面上生长。所得的甲硅烷基化木海绵显示出高的机械压缩性（可逆压缩率为60％）和弹性回复率（在40％应变100次循环后约99％的高度保持力）。木海绵具有优异的吸油/吸水选择性，吸油量高达41 gg ^–1。而且，可以通过简单的机械挤压来回收被吸收的油，并且多孔海绵在多次挤压-吸收循环时保持高的吸油能力，表现出优异的可回收性。利用多孔海绵的单向液体传输优势，成功设计了一种集油装置，可以连续地从水中分离出污染物。这种简单，低成本，可扩展的自顶向下方法在开发有效且可重复使用的油/水分离用吸油剂方面具有巨大潜力。