Nanocellulose-Graphene Oxide Hybrid Aerogel to Water Purification

Abstract

The depletion of non-renewable resources and pollution of industrial wastewater are major challenges to the human security. Using green renewable resources to address the above problems coincides with the sustainable development of human society. In this study, we attend to design hybrid aerogel, derived from nanocellulose and graphene oxide (GO), to realize wastewater purification via adsorption behavior, benefitting from its high specific surface area and high porosity. Nanocellulose, isolated from Amorpha fruticosa Linn. as a shrub plant, and graphene oxide were combinely employed to prepare the hybird aerogel via freeze-drying process; and its purification ability to remove methylene blue(MB), congo red (CR) and waste oil in waste water was tested. The results indicate that the isolated nanocellulose bears abundant hydroxyl groups and high aspect ratio of ~500 with average diameter of ~30 nm, which is well distributed on the surface of graphene oxide sheet with side length of about 1~3 μm, both of which form the hybrid aerogel with porosity larger than 99%. The nanomaterials physically assemble its orignial aggregation state. When the mass ratio of nanocellulose and graphene oxide is 8 : 2, the hybrid aerogel reaches the highest adsorption capacity of 265.6mg/g and 21.5mg/g for MB and CR, respectively. The hybrid aerogel after hydrophobic treatment shows excellent oil adsorption capacity up to 25.6 g/g, which is beneficial to oil/water separation. This strategy provides potential great-application of the nanocellulose in water purification.