Preparation of graphene modified melamine sponge and solar-assisted cleanup of heavy oil spills

Cleaning up offshore oil spills is a problem worthy of attention. At present, most of the research focuses on the field of light oil treatment, while heavy oil is difficult to be quickly and effectively adsorbed and recovered because of its high viscosity. Two kinds of graphene modified melamine sponge (RGOMS and HRGOMS) was prepared by squeezing impregnation of graphene oxide (GO) and high-temperature reduced graphene oxide (HRGO), respectively, in this work. The materials were comprehensively analyzed by FT-IR, SEM, hydrophobic angle test, photo-thermal conversion evaluation and heavy oil adsorption tests. It can be seen that the load of graphene in RGOMS increases with both of GO suspension concentration and impregnation times, which improves its photo-thermal conversion performance. However, because the accumulation of excess graphene layers causes blocking of the pores, its saturated adsorption capacity reduces. When the concentration of GO suspension is 3 mg mL(-1), with 1 time impregnation, the comprehensive performance of RGOMS (named RGOMS-3-1) is the best. However, HRGOMS cannot perform as good as RGOMS-3-1, significant falling off of HRGO powder taking place after repeated mechanical extrusion. The thermal conductivity of RGOMS-3-1 can reach 0.253 W.m(-1).K-1. Under light conditions, its adsorption rate on heavy oil can be increased to 8 times that the light is off, and its saturated adsorption capacity can reach 111 times of its own. While HRGOMS shows lower adsorption rate and adsorption capacity on heavy oil under the same conditions.