Preparation and properties of monolithic and hydrophobic gelatin–silica composite aerogels for oil absorption

In this study, highly porous and low density silica–gelatin composite aerogels with excellent absorption capacity were obtained. The preparation process was as follows: firstly, the gel with stable network structure was formed by sol–gel method; secondly, after soaking the gel with hexamethyldisilazane solution, the aerogel was prepared by freeze-drying; finally, the aerogel was coated with hexamethyldisilazane via chemical vapor deposition. The composite aerogels with 30% gelatin showed optimal performance in practical applications: lowest bulk density (0.068 g/cm3), highest porosity (96%), largest pore volume (1.24 cm3/g), and maximum oil/organic solvents absorption capacity (12–27 g/g). The excellent oil/solvent absorption capacity and recyclability indicated that the hydrophobic gelatin–silica composite aerogels could be a promising candidate for oil absorption.