Mechanically robust polybenzoxazine/reduced graphene oxide wrapped-cellulose sponge towards highly efficient oil/water separation, and solar-driven for cleaning up crude oil

Abstract Cleaning up spilled crude oil and recycling oily wastewater are global challenge. For the first time, we develop a simple approach to fabricate solar-driven superhydrophobic/oleophilic polybenzoxazine/reduced graphene oxide wrapped-cellulose sponge (PBZRGOS) for highly efficiency oil/water separation and rapidly crude oil cleaning up from water. Polybenzoxazine (PBZ) is introduced into the cellulose sponge as a binder to provide low surface energy. Reduced graphene oxide (RGO) is anchored tightly on the sponge skeleton with the aid of PBZ for fabricating a thermal conductive path. The resultant PBZRGOS with 5% content of RGO (PBZRGOS5) exhibited robust mechanical stability after 100th compression process and maintained ultrahigh oil/water fluxes (up to 107428 Lm-2 h−1 bar−1) under 0.10 bar as well as high oil/water separation efficiency (99.1%) after 10 cycles, which is superior to other reported modified sponges. Moreover, the light-heat conversion capacity of PBZRGOS driven by solar energy obviously reduce the viscosity of crude oil, speeding up crude oil-diffusion coefficient, and thus achieve the saturated adsorption capacity up to 61.1 g/g with one sun, which is 15.7 times higher than that of the PBZRGOS without sunlight. Therefore, it is expected that this self-heating and superhydrophobic cellulose sponge can be utilized as a competitive functional sponge for cleaning up spilled crude-oil in the large area water body.