Photothermally responsive, magnetic and flame-retardant MOF-based polyurethane sponges for oil/water separation and emulsion purification

The development of a multifunctional sponge with photothermal effect for adsorbing high-viscosity oil, as well as magnetic drive and excellent flame-retardant property, is significant in the field of oil/water separation, but also extremely challenging. In this work, a multifunctional MOF-based polyurethane (PU) sponge was successfully prepared using a simple method. Fe 3 O 4 -loaded NH 2 -MIL-101(Fe) nanoparticles were immobilized on PU sponge via low surface energy polydimethylsiloxane (PDMS) to obtain superhydrophobic NH 2 -MIL-101(Fe)@Fe 3 O 4 @PDMS@PU sponge (WCA = 155.6°), which exhibited excellent oil absorption, oil/water selectivity and reusability. The introduction of NH 2 -MIL-101(Fe)@Fe 3 O 4 endowed the modified sponge with excellent photothermal properties, which was manifested in that with the help of solar energy, the sponge heated up rapidly and could achieve efficient adsorption of high viscosity oil. The magnetic property of the modified sponge made it effectively separate oil and water mixture along a certain path under the control of a magnetic field. In addition, the NH 2 -MIL-101(Fe)@Fe 3 O 4 @PDMS coating made the sponge exhibit excellent flame retardancy, which could effectively improve the safety of the modified PU sponge in practical applications. In summary, NH 2 -MIL-101(Fe)@Fe 3 O 4 @PDMS@PU sponge has potential application prospects in the oil/water separation field.