Superhydrophobic silk fibroin-silica melamine sponge for efficient oil–water separation

This study developed a facile and environmentally-friendly method to prepare SiO2/silk fibroin (SF) composite melamine sponges modified using SF and hydrophobic SiO2 nanoparticles (NPs). During the preparation procedure, the SiO2 NPs were bonded to skeletons of porous sponges with the SF binding agent using a dip-coating method. The SiO2 NPs and SF with hydrophobicity constructed a rough surface. The obtained sponges possess a high absorption capacity of 70.9–160.8 times of its weight for various oils and organic solvents and a high water-contact angle greater than 151°. More importantly, the modified sponges showed good recyclability, and could return to its original shape even after 100 cyclic compression. The as-prepared sponge also showed high buoyancy outstanding elasticity, and maintained high absorption capacity even after 10 cycles of repetitive absorption-desorption. The prepared sponges could efficiently separate oil or organic solvents from oil–water mixtures, indicating that the SiO2/SF/MS sponges are promising candidates for remediating oil spills and oily wastewater.