Superwetting functional polyurethane as a promising selective oil-absorbing porous material for oily water treatment

Oil spills and industrial oily wastewater during petroleum and chemical production and transportation have caused serious damage to water resources and the environment. Therefore, it is of great significance to develop new materials and new methods for oil pollution control. Recently, polyurethane (PU) polymers have been proven to be promising candidates for the fabrication of superhydrophobic and superoleophilic materials for oil–water separation due to their low cost, strong absorptive capacity, good elasticity, and ease of large-scale manufacturing. In this review, we summarize the recent advances of superhydrophobic PU-based materials for oil–water separation. The synthesis methods of porous PU based two-dimensional (2D) membrane and three-dimensional (3D) foam are introduced. Furthermore, the strategies of modifying the PU-based foam to enhance its superhydrophobicity through the synergistic effect of increasing surface roughness and reducing surface energy are highlighted, which greatly promotes its application in oil–water separation. Finally, the common methods for the recycling of oil-absorbing materials are discussed. This work has important reference significance for PU-based materials in solving oil pollution.