Superhydrophobic sponge containing silicone oil-modified layered double hydroxide sheets for rapid oil-water separations

The demand for superhydrophobic sponges for fast oil-water separations is growing. Herein, a novel superhydrophobic sponge was developed using a facile and scalable synthetic procedure. Briefly, layered double hydroxide (LDH) sheets were first modified with polymethylhydrogen silicone oil (PMHS) to give superhydrophobic LDH sheets (SHP-LDH). Subsequently, the SHP-LDH sheets were immobilized at different loadings on a polyurethane sponge using a silane coupling agent (KH-550). A SHP-LDH-containing sponge (SHP-LDH loading of 25 wt.%) demonstrated outstanding oil-water separation performance, which can be attributed to its super-lipophilic character, high oil absorption capacity, good oil storage properties and ease-of-recovery following oil absorption. In addition, the superhydrophobic sponge also displayed excellent flame retardancy. On account of the low cost and readily available of the raw materials used in its fabrication, the simplicity of its fabrication and outstanding performance, the superhydrophobic sponge is expected to find widespread use in oil-water separations and other applications.