Hydrophobic sponge derived from natural loofah for efficient oil/water separation

Polymer sponge and carbon aerogel have received widespread attention because of their high specific surface area and controllable wettability. However, the complex manufacturing processes and non-renewable raw materials of these porous materials have limited their practical applications. Herein, we conducted the thermal chemical vapor deposition (CVD) of hydrophobic methyltrichlorosilane (MTCS) on loofah sponge (LS), which led to the formation of a novel oil-adsorbing hydrophobic MTCS-coated loofah sponge (MTCS-LS). The obtained MTCS-LS retained the interconnected 3D porous structure and robust structure stability of natural LS, while exhibited dramatically improved hydrophobicity with contact angle of 137° in the pH range of 2–12. This unique characteristic conferred MTCS-LS selective oil removal ability from water, and MTCS-LS possessed oil sorption capacity of 13 times of its dry weight and high separation efficiency (>92%). Results of the adsorption-squeezing tests proved that the excellent reversible compressibility of natural LS was maintained after the silanization modification. Compared to other known oil-adsorbing materials, the MTCS-LS displayed apparent advantage in adsorbing oils with high viscosity (e.g. crude oil). Our study provides a simple approach to exploitation of biomass in pollutants removal.