Multifunctional plant fiber sponge integrated with polypyrrole and magnetic Fe₃O₄ nanoparticles for enhanced all-weather crude oil spill cleanup via photothermal and magnetic-thermal synergy

As environmental pollution intensifies, particularly due to the severe ecological threats posed by crude oil spills, there is an urgent need to develop hydrophobic/oleophilic porous absorbents with self-heating capabilities. These absorbents can reduce crude oil viscosity through in-situ heat transfer, thereby accelerating the remediation process. Herein, A novel multifunctional and compressible sponge (m-PFS@PPy@Fe₃O₄) is developed by self-assembling PPy, Fe₃O₄ nanoparticles, and polydimethylsiloxane onto the plant fiber sponge. The m-PFS@PPy@Fe₃O₄ exhibits high hydrophobicity and excellent compressibility, making it highly effective in separating oil-water mixtures with a high oil absorption capacity (24.7 ∼ 53.5 g/g). Due to the synergistic effect of photothermal and magnetic-thermal properties, the surface temperature can rapidly rise from 28.0°C to 96.9°C under 1 sun irradiation and 54.2°C under a specific magnetic field. This heat generation, effective in all weather conditions, overcomes limitations related to both weather and energy. The generated heat is transferred to the oil, significantly reducing its viscosity and speeding up the oil absorption process. More importantly, the sponge can be connected to a vacuum pump-assisted absorption device, enabling continuous recovery of crude oil from the water surface under sun irradiation or magnetic field, demonstrating great potential for highly efficient remediation of viscous oil spills.