Oil/water separation with hydrophobic/oleophilic silica-shelled cellulose aerogels

In this work, hydrophobic/oleophilic cellulose/SiO2 aerogels are prepared by coating cellulose aerogels which are prepared from freeze-drying aqueous cellulose solutions with a layer of silica shell and then hydrophobizing the surface by reacting with vaporized methyltrimethoxylsilane. With the cellulose content in the aqueous solution increases from 0.5% to 1.25%, the density of the cellulose/SiO2 aerogel increases from 28.92 mg/cm(3) to 34.83 mg/cm(3), and the porosity decreases from 90.2% to 84.48%. The structure and composition of cellulose/SiO2 aerogel are analyzed with SEM, FT-IR, XPS, and TGA. The surface wettability investigation indicates that the prepared cellulose/SiO2 aerogels have excellent hydrophobicity and oleophilicity, with a water contact angle up to 143 degrees and an oil contact angle down to 0 degrees. The results of oil absorption experiments show that the absorption capacity of the aerogels for oils and organic solvents is 16 similar to 40 times their own mass. In addition, as the aerogels are hydrophobic/oleophilic, they demonstrate good oil-selective absorption performance in oil/water mixture. Moreover, experimental results in oil absorption under high temperature conditions and acidic/basic conditions indicate that the aerogels have exceptional resilience towards arduous conditions. These advantages render them a viable option for remediation of water pollution resulted from oil contamination.