Superhydrophobic and super-oleophilic natural sponge sorbent for crude oil/water separation

In this study, the separation of hydrocarbon derivatives from the water surface, one of the world's significant problems and challenges, was solved by synthesizing a superhydrophobic and super-oleophilic luffa sponge (LS) in an easy, inexpensive, and environmentally friendly way. Using design expert 12 software, the values of graphene, wax, and time to absorb oil from the water surface were optimized. The optimal amounts of graphene, wax, and time were obtained at 0.108 g, 0.338 g, and 2.587 minutes, respectively. The TGA analysis showed that the modified luffa sponge was temperature decomposed between 348.1 and 394.3 °C and finally decomposed and carbonized completely at 497.2 °C. Also, the modified luffa sponge's hydrophobicity was investigated by contact angle analysis. The results displayed that the modified sponge's contact angle with wax and graphene was 158°, which confirmed the modified luffa sponge's super-hydrophobicity. In addition, the sorption efficiency of the modified Luffa sponge was higher than 91.32%, and oil/water sorption capacity was larger than 11.92 (g/g). Also, the average oil of recovery after 10 cycles maintains separation sorption of around 91.32%. Finally, luffa sponge/ graphene/ carnauba and beeswax can be used as biodegradable, super-hydrophobic, and super-oleophilic sorbents in the industry.