Fabrication of nanocellulose-based high-mechanical and super-hydrophobic xerogels for speedy oil absorbents

Cellulose-based porous materials are promising for various fields and preferred for sustainable development. However, the low mechanical properties and high hydrophilicity of cellulose-based xerogels had a direct influence on their application in oil absorption. To address the challenge, an environmentally friendly and economical method for synthesizing MTMS/C0.2-TOCN0.9 xerogels with high hydrophobicity and excellent mechanical strength was successfully established. In this work, shape-recoverable using nanocellulose (TOCN)based xerogels with porous structure (porosity of 91.5-98.7 %), as well as excellent hydrophobic properties were prepared by TOCN-stabilized wet foams with physical crosslinking, ice crystal-induced phase separation and MTMS modification through simple air-drying instead of the traditional freeze-drying. At the optimized ingredients of TOCN and crosslinker (Ca2+), the xerogel (MTMS/C0.2-TOCN0.9) exhibited superior compressive performance (approximately 35 KPa) and exceptional structural stability after 50 cycles at a compression deflection of 60 %, which was still maintained at 71.5 % of the original stress. Moreover, the MTMS/C0.2TOCN0.9 xerogel achieved stable superhydrophobicity (128.3 degrees) and excellent oil absorption capacity (59.6 g/ g), rendering it a desirable adsorbent for oil spill cleaning. Compared to the pseudo-first-order model, the pseudosecondary model had higher validity in oil absorption kinetic theories. The MTMS/C0.2-TOCN0.9 xerogel was recyclable and nontoxic, which has the potential to promote environmental applications.