Magnetic luffa/graphene/CuFe2O4 sponge for efficient oil/water separation

In this study, a novel magnetic composite material comprising luffa sponge derived graphene aerogel embedded with hollow CuFe2O4 nanospheres (LGN) is successfully synthesised for the first time by a clean and low-cost one-step solvothermal electrostatic co-assembly method. The resultant LGN aerogel exhibits superhydrophobic and superoleophilic properties with the water and oil contact angles of 162.1° and 0°, respectively, along with magnetic properties characterized by the saturation magnetization of 51.6 emu/g, and a large specific surface area of 218.8 m2/g. The saturation sorption capacity of LGN for organic solvents/oil is found to be in the range of 47.6–86.8 g/g, exhibiting an excellent oil/water emulsion separation ability. Through the capillary action, oil and organic solvents spontaneously penetrate into the interior of the aerogel, while the superhydrophobic surface prevents water from entering, thereby enabling the separation of oil and water. These characteristics enable the real-time sorption of organic pollutants from water, with the capability of exhausted sorbent being regenerated. Notably, even after 20 sorption-volatilisation cycles, the saturated sorption capacity of LGN remained high at the 92.2 % of the initial value, demonstrating a remarkable recycling performance. In addition, LGN can exhibit an oriented sorption performance by controlling the applied magnetic field, enabling sorbent recycling even under extreme environmental conditions. Such an effective strategy offers a new route to high value utilisation of biomass waste with significant potential in the field of oil spill treatment.