Layer‐by‐Layer Assembly Fabrication of Porous Boron Nitride Coated Multifunctional Materials for Water Cleaning

Cleanup of oil spills and industrial discharge of organic solvents is a global challenge. However, development of the ideal materials for water remediation with a high separation efficiency and low risk of fire is still rather sparse because the material needs to be superhydrophobic/superoleophilic and also flame‐retardant. Here, a novel coating material of porous boron nitride nanosheets (BNNSs) and a layer‐by‐layer assembly technology for tailoring inexpensive cotton fabric and melamine sponge with these desired properties are reported. The BNNS‐coated cotton fabric and melamine sponge exhibit high oil/water separation efficiency, selective absorption capacity of oil and organic solvents, and excellent recyclability. Furthermore, the coated materials show an efficient flame‐retardant effect which completely stops melamine sponge melt dripping upon exposure to the direct flame from a butane blowtorch within 52 s. The integrated advantages of the high porosity, low water adhesion, compressibility, strong fire‐resistance, simple operation, and commercial availability enable the porous BNNS‐coated cotton fabric and melamine sponge to satisfy various practical oil/water separation requirements.