Graphene sponge as an efficient and recyclable oil sorbent

Fructose, an environmentally friendly reducing agent, was chosen during the process of reduction and self-assembly of graphene oxide (r-GO) via the hydrothermal method to prepare the graphene sponge (r-GS). Graphite oxide (GO) was prepared by oxidizing graphite (G) powders through a modified Hummers method. The GO dispersion (10 mg/mL) was mixed with equal mass ratio of fructose and ultrasonic-assisted dispersing in a beaker at RT for 30 min. Then, the suspended solution was transferred to a 200 mL Teflon-lined autoclave and maintained at 160 °C for 6 h. After cooling to RT, the black rod was washed with deionized water and lyophilized to obtain r-GS. The samples were characterized by XRD, TEM/SEM, BET, EA, FTIR, Raman and TPR. The absorption capacity and recycling measurement for oil over the fabricated r-GS was evaluated. In the preliminary results, the hydrophobic r-GS showed light weight and formed 3D porous structure that could enhance the absorption of organic solvents and oils. The absorption capacities of r-GS for various organic solvents and oils were quantified. The absorption capacities were in the range of 15 ∼ 38 g/g. The ultrahigh absorption capacity indicates that the absorption is more like an accommodation of oils in the hydrophobic micro- and macro-pores of the r-GS. In particular, the absorption capacity for vegetable oil is 37.8 g/g, indicating that the r-GS can be used for oil leakage treatment.