Polydopamine/MXene Nanosheet/Polyaniline/Polydimethylsiloxane Foams for Oil–Water Separation

It remains a huge challenge to clean leaks of oil and various organic solvents quickly and efficiently, especially for special conditions such as high-viscosity oils, corrosion from acid/alkali solutions, high-temperature damage, and fire risk. The adsorbents with a three-dimensional porous structure and excellent resilience have been recognized as prospective candidates for dealing with oil–water separation problems. In this study, solar responsive and multifunctional polyurethane foams were successfully fabricated by compounding photothermal and hydrophobic components by both internal and external means. Due to the interface adhesion, polydopamine/MXene nanosheet/polyaniline/polydimethylsiloxane polyurethane (PMPP–PU) foams prepared by introducing PDA/MXene nanoparticles and phytic acid (PA)/PANI micronano coatings exhibited a high adsorption capacity up to 61.4 g/g for different kinds of low-viscosity organic solvents. Driven by 1 kW/m2 illumination intensity, the adsorption capacity of PMPP–PU for high-viscosity oil increased to 29.4 g/g, realizing a 203% rise compared to pure PU. Also, the modified foams achieved rapid extrusion and cyclic adsorption of adsorbed solvents, and PMPP–PU showed an adsorption efficiency of close to 90% after 20 cycles. Besides, the prepared adsorbent foams remained persistent and maintained stable hydrophobicity under extreme environmental conditions and were not significantly damaged even by fire attack. This work presents a competitive strategy for the separation and recovery of low-viscosity organic solvents and high-viscosity oils.