Environment-Friendly superhydrophobic sponge for highly efficient Oil/Water separation and microplastic removal

The pollution of water resources by oils and microplastics is a significant global issue affecting the environment and human health. However, developing a sustainable multifunctional adsorption material to remove multiple pollutants has always been a challenge. Herein, an eco-friendly superhydrophobic polyurethane sponge was developed using polydimethylsiloxane (PDMS) and dehydroabietic acid grafted Al2O3 nanoparticles by dipcoating technique. The green dehydroabietic acid has strong hydrophobicity, which can make the coated sponge have excellent separation of oil/water mixtures or emulsions and has a high oil absorption capacity (20-55 g/g) for various kinds of oils. Continuous oil/water separation was also achieved by gravity-driven or with the assistance of peristaltic pump. After 10 separation cycles, the coated sponge still exhibits excellent separation efficiency (greater than 97%) due to its outstanding mechanical durability and compressive performance. Moreover, various kinds of microplastics could be efficient captured from the aqueous solution at a higher rate using the coated sponge, which is mainly due to the capillary force of the coated sponge and the noncovalent force and conjugates between PDMS and microplastics. This work provides a new strategy to fabricate a sustainable multifunctional sponge for oily wastewater and microplastics and shows the great potential for largescale practical application.