Layer-by-layer assembly fabrication of porous boron nitride coated multifunctional materials for water cleaning

© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 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.