Plant Polyphenols as Multifunctional Platforms To Fabricate Three-Dimensional Superhydrophobic Foams for Oil/Water and Emulsion Separation

Taking plant polyphenols as multifunctional platforms, we developed an environmentally friendly surface decoration strategy for preparing new types of three-dimensional (3D) superhydrophobic foams. The superhydrophobic foams were fabricated by in situ growth of beta-FeOOH nanoparticles on melamine foams that were pretreated by noncovalent surface decoration of plant polyphenol-glutaraldehyde cross-linkage, followed by the Michael addition of 1-dodecanethiol to plant polyphenols. The as-prepared superhydrophobic foams had water contact angles of 154.93 degrees and 153.12 degrees on the exterior and interior surfaces, respectively. The superhydrophobic foams featured a large absorption capacity, high mechanical robustness, structural stability, and flame resistance. During the 100 cycles of absorption and squeezing, the loss of absorption capacity was as low as 0.14% per cycle. In a continuous separation process, organic pollutants were successfully removed from water with a separation efficiency of 98.0%. Notably, the 3D superhydrophobic foams successfully separated six types of oil/water microemulsions, with a peak separation efficiency of 99.82%.