Carboxylated Wood-based Sponges with Underoil Superhydro-philicity for Deep Dehydration of Crude Oil
Water cut crude oil needs to be deeply dehydrated before further transportation or refinery, because the water residuals not only increase the transportation cost and energy consumption tremendously, but also are harmful for the oil delivery pipelines and refining equipments. Herein, we report carboxylated wood-based sponges (CWS) with underoil super-hydrophilicity for removing water residuals from crude oil. These CWS are made up of aligned cellulose nanofibers after getting rid of lignin and hemicellulose in natural balsa wood. The removal of lignin and hemicellulose breaks the thin cell walls of balsa wood, resulting in a lamellar structure for the freeze-dried CWS. This lamellar architecture endows the CWS with high mechanic compressibility and good elastic recovery. The CWS show fast and effective dehydration for crude oil with water residuals as low as 20 ppm. The absorbed crude oil can be easily recovered from the CWS by simple squeezing. Besides, the CWS are not only reused without performance decline during long-term operation, but also show good chemical stability even in strong acidic and basic surroundings. These results indicate that the CWS have great potentials in the deep dehydration of curde oil, especially for those water-in-crude oil emulsions.