Solar-driven superhydrophobic modified polyurethane sponge for rapid in-situ recovery of oil and microplastics in marine oil spill co-contamination

Given the advantages of facile in-situ adsorption for addressing the increasingly severe co-pollution of oil and microplastics (MPs) in marine environment, an ultralight, elastic, superhydrophobic/superoleophilic polyurethane sponge (PTPU sponge) with solar harvesting capability was developed. Sequential modification with polydopamine, MoS, and n-octyltrichlorosilane via dip-coating method endowed the sponge with exceptional oil adsorption capacities (36.46-85.52 times its weight) through strong capillary action and mussel adhesion effects. Under 1.0 sun illumination, the PTPU sponge rapidly achieved photothermal conversion, self-heating to 45.6 °C within 20 s. Thermally reducing the oil viscosity enabled rapid oil permeation for decontamination and easy oil desorption for sponge reuse. Consequently, the in-situ continuous oil-water separation system achieved an average separation rate of 51.24 × 10 kg m h for crude oil. After 50 cycles, the mass of recovered oil decreased by ∼15 %, indicating the excellent durability and reusability of this adsorbent. Simultaneously, the PTPU sponge demonstrated remarkable removal efficiency for typical micro- and nano-plastics (1540-1720 mg g) during oil adsorption in real seawater background. High seawater salinity insignificantly impacted oil or MPs adsorption by PTPU sponge, highlighting its practical potential for marine oil spill remediation. This work provides novel insights for developing energy-saving, practical, and efficient in-situ marine oil remediation technologies.