▎ 摘　　要

In this work, a simple preparation method is developed to synthesize aerogels with great shape retention for oil absorption application. First, an elastic aerogel is prepared by ice-templating an aqueous suspension of cellulose nanocrystal (CNC) with polyethyleneimine (PEI) and epoxy cross-linker. After the lyophilization process, the prepared CNC aerogel shows highly porous structures and allows rapid absorption of solvents, including water, through capillary forces. In particular, the aerogel after compression recovers to its original shape without any deformation. To realize selective oil absorption, chemically modified graphene sheets are attached to the aerogel pore surface via a dip coating process. SEM images show that the graphene sheets form a uniform and dense monolayer on the pore surfaces of the CNC aerogel. This graphene coating improves hydrophobicity without compromising the overall porosity and elasticity of the aerogel. After surface modification, the CNC/graphene aerogel can selectively absorb organic solvents with a weight ratio ranging from 25 to 58 g/g. The CNC/graphene aerogel can be squeezed dried into a compact size, and retains its original shape rapidly in contact with liquids. The absorbed liquids can be collected by mechanical squeezing, and the absorption performance of this aerogel remains unchanged after 100 squeezing-swelling cycles. Several examples are also demonstrated to show the feasibility of applying this aerogel in oil spill control. (C) 2020 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.