Efficient oil-water separation using superhydrophobic OPA-MOF-5@PDMS@PU sponge for environmental remediation

Abstract

Oily wastewater, especially oil-water emulsions, has caused severe environmental damage. It is urgent to develop a simple, efficient superhydrophobic and superoleophilic material to address this issue. In this work, a multifunctional sponge based on MOF was proposed. The hydroxy-assisted method was employed to prepare MOF-5 with metal coordination centers. Subsequently, octadecylphosphonic acid (OPA) was used to hydrophobically modify MOF-5 to prepare stable and hydrophobic OPA-MOF-5. Polydimethylsiloxane (PDMS) with low surface energy was employed as the adhesive, and the hydrophobic OPA-MOF-5 was loaded onto the polyurethane (PU) sponge to obtain the stable superhydrophobic OPA-MOF-5@PDMS@PU with a WCA of 155.9°. The produced modified sponge exhibited high sorption capacity and oil-water separation efficiency, with a sorption capacity of 26.7 (petroleum ether)-85.6 (chloroform) g/g and a separation efficiency of over 99 %. It has also shown satisfactory emulsion purification and flame retardancy capacities.