Coating polyurethane sponge with Dy-MOF for efficient oil-water separation in complex environments

Leakage of industrial oil and organic solvents seriously harms environment and ecology yet demanding highly efficient and durable materials for oil-water separations. In this work, ultra-light and highly flexible poly-urethane (PU) sponges were engineered to 3D oil-water separators by coating the dysprosium metal organic framework (Dy-MOF) onto the surfaces of the PU frames. Through a facile impregnation, the Dy-MOF was attached to the full frames of the sponges. Consequently, liquid contact surfaces were extended from these on top layers to the whole rack. Superhydrophobicity with water contact angles up to 152.08 degrees and lipophilicity enable continuous separations of dichloromethane from water through the resulted Dy-MOF@PU sponges in a contin-uous mode. The modified sponges own high gravimetric absorption capacities for oil and organic solvents, and high resistances to temperature variations, corrosive solutions, and mechanical abrasions, thanks to the well-connected and stable superhydrophobic/supportive interfaces. An efficient separation was successfully piloted for oily wastewater consisting of water-in-oil emulsions stabilized by surfactants, demonstrating the potential of practical water treatment of Dy-MOF@PU in complex environments. Mechanism leading to superior oil-water separation capability was studied and inferred as the combined effects of the physical and chemical properties arisen from the stable Dy-MOF and flexible but porous matrix.

Automated summary

In this study, ultra-light and highly flexible poly-urethane sponges coated with dysprosium metal organic framework (Dy-MOF) were developed as 3D oil-water separators. The modified sponges exhibited superhydrophobicity and lipophilicity, enabling continuous separation of dichloromethane from water. These sponges also had high absorption capacities for oil and organic solvents, as well as resistance to temperature variations, corrosive solutions, and mechanical abrasions. The study demonstrated the potential of Dy-MOF@PU sponges for practical water treatment in complex environments.