A lignin-based carbon aerogel enhanced by graphene oxide and application in oil/water separation

A lignin-based carbon aerogel enhanced by graphene oxide (LCAGO) is fabricated. As the strong reaction between amine groups from lignin derivates and carboxylic groups from GO and acrylic acid (AA), the compactness and the cross-linkage of the gel are much higher than the samples without lignin derivate and GO. The lignin derivates are used as cross-linkers and GO contributes to reach to super-hydrophobicity with a low annealing temperature and improves the mechanical performance after annealing. The carbon aerogel achieves a water contact angle of 150 degrees at 350 degrees C for 2 h, achieving the energy-saving purpose. The synergistic effect of super-hydrophobicity and good mechanical property acquired by lignin derivate and GO ensures the carbon aerogel appropriate for oil/water separation and light oil, heavy oil and emulsified oil are separated respectively by the gel. The oil adsorption ratio is about 32-34 g/g and shows a moderate performance, which is compared with the reported biomass-based materials. The results indicate the material is a highly effective and practicable water-cleaning material. The preparation process is energy-saving and is a pathway for separation and collection oil from water with industry waste.