Wood sponge with photothermal, magnetically driven, and superhydrophobic characteristics for high-viscosity oil–water separation

In this work, naturally degradable porous balsa wood was used as a raw material to prepare a highly elastic wood sponge (WS) substrate using a two-step chemical method and a freeze-drying method. The surface hydrophobic modification of Fe3O4 nanoparticles using the fluorine-free material octadecyltrimethoxysilane (C18TMS) solved the problem of agglomeration caused by the high nanoparticle surface energy. Polydopamine (PDA), hydrophobically modified Fe3O4 (C18TMS/Fe3O4), and low-surface-energy polydimethylsiloxane (PDMS) were sprayed onto WS substrates using a simple spraying method. An environmentally friendly adsorption sponge with photothermal, magnetically driven, and superhydrophobic properties was prepared for the first time using this method. The prepared sponge had a water droplet contact angle of 156.8° and exhibited excellent oil–water separation performances. Due to the addition of PDA and Fe3O4, the modified sponge exhibited excellent photothermal performance, rapidly heating to 63.4°C under a sunlight intensity of 1 kW m−2. The superhydrophobic WS prepared in this experiment provides a more environmentally friendly and low-cost way for high viscosity oil–water separation and targeted removal of oil pollution. [Display omitted] •Preparation of environmentally friendly sponge substrate using natural balsa wood as raw material.•Fe3O4@PDA@WS has excellent superhydrophobicity, photothermal effect, and magnetic driving performance.•Fe3O4 particles firmly adhere to WS under the adhesion of PDA, enhancing the firmness of the hydrophobic coating.•Hydrophobic modification of Fe3O4 using C18TMS to enhance dispersion.•The prepared sponge can be used for high viscosity oil/water separation.