Hydrophobic and oleophilic carbon fiber aerogel for oil/water separation

Hydrophobic and oleophilic carbon fiber aerogel (CFA) was produced from lignocellulosic biomass such as black locust, hybrid polar, and chestnut shell. The biomasses were treated by some chemicals to prepare hydrophilic cellulose aerogel (CA). Successive freeze-shaping in liquid nitrogen (− 196 °C) and freeze-drying at − 53 °C and 0.113 mbar formed the hydrophilic cellulose aerogel (CA). Then, carbonization of CA at 900 °C yielded ultralight (0.011 g/cm³) and mesopore-rich (38 nm) hydrophobic/oleophilic CFA with moderate surface area (110–533 m²/g) and pore volumes (0.25–0.73 cm³/g). Water contact angle, surface functionalities, cellulose crystallinity, morphology, surface area, and thermal stability of CFA were characterized. Water contact angle of CFA reached 141° that indicates highly hydrophobic nature. Although no chemical activation was applied, the oil sorption capacities of 76.0, 81.6, and 81.8 g/g were achieved for diesel oil, crude oil, and sunflower oil, respectively.