Multifunctional esterified nanocellulose aerogel: impact of fatty chain length on oil/water separation and thermal insulation

A sustainable esterification approach has been used to developed for the superhydrophobic functionalization of nanocellulose-based aerogel. The preliminary study emphasizes the effect of fatty acid chain length on the properties of esterified aerogel. The reported aerogel was constructed through a two-step method, freeze-drying and dip-coating, and its 3D interconnected porous structure was evaluated through FE-SEM and BET techniques. The wettability analysis showed that with increasing fatty chain length, the wettability of the surface changes from hydrophilic to superhydrophobic. Further, the modified aerogels were used for crude oil sorption in homogeneous and heterogeneous mediums. In the study, it has been observed that C18 modified aerogel shows better performance having the highest oil/water separation efficiency. The isotherm and kinetic analysis were performed to study the sorption mechanism of crude oil on aerogel, and it has been revealed that the absorption of crude oil is spontaneously favourable, and the estimated sorption capacity was 60 g/g. The same mesoporous material was tested for thermal insulation analysis due its low thermal conductivity (030–0.035 W/mK).