Robust and ultralight biofoams had been successfully prepared using readily available and biocompatible cellulose nanofibrils (CNFs) as the matrix. The γ-glycidoxypropyltrimethoxysilane (GPTMS) was first added into the CNFs suspension to act as a crosslinker to form covalent linkages between cellulose chains. Then the gelatin was incorporated into the networks via reacting with the epoxy groups on GPTMS and forming hydrogen bonding with CNFs. The content of gelatin had a significant influence on the properties of the obtained foams. With the introduction of a small amount of gelatin, the foams exhibited significantly enhanced mechanical properties and stability in water in comparison with the CNF foams without GPTMS and/or gelatin. The foams containing the appropriate ratio of gelatin to CNFs possessed the high porosity (99.16%), ultralow density (0.0077 g/cm³), good mechanical properties, and abundant functional groups (hydroxyl and carboxylate groups). These features made it an ideal adsorbent toward methylene blue (MB) and the maximum adsorption capacity could reach up to 430.33 mg/g. Additionally, the cationic MB could be removed from the mixed cationic/anionic dye solutions with high selectivity, possibly due to the strong electrostatic interactions between MB and the adsorbent. Furthermore, the recycling test demonstrated the good reusability of this biofoam. Therefore, this work provides an environmentally benign method to fabricate robust CNF-based foams, which can be considered as green adsorbents for the treatment of water pollutants.

使用容易获得且生物相容的纤维素纳米原纤维（CNF）作为基质，已经成功制备了坚固而超轻的生物泡沫。首先将γ-环氧丙氧基丙基三甲氧基硅烷（GPTMS）添加到CNF悬浮液中，以充当交联剂，从而在纤维素链之间形成共价键。然后，通过与GPTMS上的环氧基反应并与CNF形成氢键，将明胶掺入网络中。明胶的含量对所得泡沫的性能有重大影响。与不含GPTMS和/或明胶的CNF泡沫相比，引入少量明胶后，泡沫在水中的机械性能和稳定性大大提高。含有适当比例的明胶和CNF的泡沫具有高孔隙率（99.16％），³），良好的机械性能和丰富的官能团（羟基和羧酸根基团）。这些特性使其成为理想的亚甲基蓝（MB）吸附剂，最大吸附量可达430.33 mg / g。另外，可能由于高选择性地从MB与吸附剂之间产生强静电相互作用，从混合的阳离子/阴离子染料溶液中除去了阳离子MB。此外，回收测试证明了这种生物泡沫的良好可重复使用性。因此，这项工作提供了一种环境友好的方法来制造坚固的基于CNF的泡沫，该泡沫可被视为用于处理水污染物的绿色吸附剂。