Plant polyphenol-inspired nano-engineering topological and chemical structures of commercial sponge surface for oils/organic solvents clean-up and recovery.

In our study, plant polyphenol-inspired chemistry is explored to nano-engineer the topological and chemical structures of commercial melamine sponge surface for preparing superhydrophobic sponges. Briefly, tannic acid (TA, a typical plant polyphenol) is applied to induce the co-assembly of silica nanoparticles (SiO2) and silver ions (Ag+) to form SiO2@TA@Ag nanostructures on a melamine sponge surface. After further chemical fluorination, the superhydrophobic sponge with a "lotus leaf-mimic" surface is formed. Surface topological/chemical structures, superhydrophobic property and anti-combustion characteristics of the sponge are examined by a series of characterization techniques, including scanning electron microscopy, X-ray photoelectron spectroscopy, water contact angle measurements, combustion/heating test, etc. The superhydrophobic sponge presents an adsorption capacity of 69-153 times of its own weight toward various oils/organic solvents, and exhibits excellent recycling ability evidenced by over 100-cycled uses. Continuous oil/water separation apparatus is also set up through equipping the superhydrophobic sponge on a peristaltic pump, realizing the clean-up of oils and organic solvents from water continuously. Together with the facile, easy-to-scale-up and substrate non-selective features of plant polyphenol-inspired chemistry, the superhydrophobic sponge and the surface nano-engineering method would hold great promise for the effective treatment of oil spillages and organic discharges, achieving high sustainability to energy and environment.