A hydrophobic/oleophilic silica‐cellulose composite aerogel for oil–water separation

A cellulose aerogel with very low overall density is fabricated by freeze‐drying aqueous cellulose solution. A hydrophobic/oleophilic cellulose aerogel is further fabricated by coating the cellulose aerogel with hexyltrimethoxysilane‐modified SiO2 nanoparticles. The features of the developed hydrophobic/oleophilic cellulose aerogel are characterized with density and porosity measurement, infrared spectroscopy, X‐ray photoelectron spectroscopy, scanning electron microscopy, and contact angle measurement. Finally, the oil absorption performance of the developed hydrophobic/oleophilic cellulose aerogel is investigated. The results show that SiO2 nanoparticles have been successfully loaded on the surface of the aerogel backbone after fulfillment of fabrication, and the surface of the aerogel turns to be hydrophobic/oleophilic (water contact angle 131° and oil contact angle 0°). The oil absorption experiment results show that the absorption capacity for organic solvents is from 10 to 21 times the initial aerogel weight, depending on the density of the absorbed organic solvents. In addition, the aerogel still maintains good stability in high temperature, strong acid or strong base conditions. Furthermore, the aerogel also shows good performance in separating oil from oil–water mixtures. This hydrophobic/oleophilic cellulose aerogel can be a promising choice for remedying water pollution caused by oil contamination. A hydrophobic/oleophilic silica‐cellulose composite aerogel has been developed. It shows considerable absorption capacity for oils as well as excellent selective absorption of oils from oil‐water mixtures.