Solar-heated melamine sponge decorated with Fe₃O₄ for continuous recovery of viscous crude oil

The offshore crude oil spill has caused serious environmental damage and affected the balance of the ecosystem. Due to the high viscosity and poor fluidity of crude oil, conventional adsorbents cannot effectively remove it. The heat converted from solar energy can reduce the viscosity of the crude oil, improved its fluidity, allowing it to be adsorbed by a porous material and then recycle, it is considered an effective approach. Herein, we have designed a melamine composite sponge decorated with Fe₃O₄ and modified by PDMS (MS@Fe₃O₄-PDMS) with good photothermal conversion performance, which can recover viscous crude oil with the assistance of solar energy. The surface temperature of MS@Fe₃O₄-PDMS can reach around 88.0 ℃ under the light intensity of 1 kW·m^− 2, effectively heating crude oil and accelerating its absorption. In the continuous crude oil recovery experiment, the absorption rate of MS@Fe₃O₄-PDMS reached 52.46 kg·m^− 2·h^− 1. In addition, the composite sponge has good processability, facile preparation method, and practical application potential.