Highly efficient multifunctional 3D polyurethane sponge with photothermal responsiveness for efficient oil-water separation and microplastic extraction

With the advancement of socio-economic development, the adverse effects of crude oil and microplastics on water resources have become increasingly prominent. The creation of a sustainable and versatile adsorption material capable of efficiently removing diverse pollutants remains a pressing concern warranting our attention. In response to this challenge, a multifunctional superhydrophobic 3D polyurethane sponge (PSTS) was developed by using polydimethylsiloxane (PDMS) and stearic acid modified TiO 2 nanoparticles through dip coating technology. This 3D sponge not only demonstrates the ability to effectively clean up high-viscosity crude oil spills under the influence of light and heat, but also shows excellent capabilities and broad applicability in water-oil emulsion separation, water-based organic contaminant removal, and microplastic extraction. This pioneering material showcases its superior performance and broad applicability. PSTS displays remarkable hydrophobicity, with a water contact angle (WCA) of 154±3°，water slide angle (WSA) of 5°, impressive physical/chemical resilience, and achieves an average oil-water separation efficiency exceeding 94%. It also possesses photocatalytic degradation properties, evidenced by the degradation of methylene blue solution within 6 h. Notably, this material maintains 94% separation efficiency after 7 cycles, indicating strong stability. In addition, the effect of solar radiation increased the oil/water separation efficiency of the samples, reaching a maximum surface temperature of 102 °C after solar irradiation, thus reducing the viscosity of the oil. In the light environment, the absorption capacity of its high viscosity oil is 4.675 g/g, which is much more than the absorption capacity of 1.505 g/g in the dark environment. The sample demonstrates commendable microplastics adsorption. It can adsorb microplastic particles dispersed in water within 10 s，adsorption up to 0.45 g/g. The PSTS is also highly efficient in separating emulsions, separating oil from emulsions within 3 min. Our research offers not only an innovative scheme for fabricating a multi-functional sponge tailored for oil-water separation with photothermal responsiveness and microplastic treatment but also presents valuable insights for practical applications, thereby contributing to environmental sustainability endeavors.