Facile synthesis of electrospun carbon nanofiber/graphene oxide composite aerogels for high efficiency oils absorption.

Oil contamination will seriously affect the health of water environment, so it is necessary to design ideal oil absorbents with large absorption capacity and high selectivity for effectively purify the oil contaminated water. Preparing high performance carbon aerogel for oil absorption has attracted growing attention, but challenges remain. Here we report a facile approach to fabricate mechanical strength enhanced three-dimensional (3D) nanofibrous aerogel principally through supporting agent liquid assisted collection-electrospinning technology, in which the immersion work was applied to measure the immersion capacity of nanofibers according to liquid-solid interfaces theory. Particularly, electrospun polyacrylonitrile (PAN) nanofibers (NFs) were collected directly in graphene oxide (GO) aqueous dispersion, and the continuous fibrous skeleton assembled with two-dimensional (2D) GO sheets to form open porous networks during the electrospinning process, which basically avoided the tedious preparation steps (nanofiber membrane cutting and re-crosslinking) that have been used previously. Due to the open porous networks promising structure stability of the aerogel, the GO sheets content required in the aerogel stacking process was largely reduced, and there was no strict requirement on the pre-freezing temperature and manner in the subsequent freeze-drying process. Furthermore, followed by thermal treating the PAN NFs/GO composite aerogel, fluffy carbon nanofibers/GO aerogels (CNF/GOAs) were obtained, which exhibited ultra-low density (2-3 mg/mL) and great compressibility (80%). After hydrophobic modification of polydimethylsiloxane by vapor deposition, the CNF/GOAs performed high absorption capacity (120-286 wt/wt) toward diverse oils. Owing to the fire-resistance and great elasticity, the CNF/GOAs could be recycled simply by combustion or mechanical squeeze, and still showed great absorption capacity after 10 cycles, which were feasible for large scale application.