Producing aerogels from silanized cellulose nanofiber suspension

Aerogels from biodegradable and renewable sources such as cellulose, for example, have become a promising alternative to separate oil from water. However, surface treatments are necessary to provide hydrophobic characteristics to the sorbents. This study aims to evaluate the chemical treatment of cellulose nanofibers (CNFs) with methyltrimethoxysilane (MTMS), in order to obtain hydrophobic sorbents to be used in the removal of oil spills from aquatic environments. CNFs were obtained from cellulose pulp waste by mechanical grinding, with a fiber diameter ranging from 40 to 66 nm. Four different chemical treatment methodologies were tested. The treatment of CNFs with MTMS using mechanical stirring at 500 rpm for 1 h, at 70 °C for 2 h, followed by freeze drying was the most effective one to obtain hydrophobic CNF aerogels. The samples presented a contact angle with water of 133.51°, sorption capacity in heterogeneous medium of 16.78 g g⁻¹, and oil removal efficiency of 87.9%.