Durable, magnetic-responsive melamine sponge composite for high efficiency, in situ oil-water separation

The development of durable and high-performance absorbents for in situ oil-water separation is of critical importance for addressing severe water pollution in daily life as well as for solving accidental large-scale oil spillages. Herein, we demonstrate a simple and scalable approach to fabricate magnetic-responsive superhydrophobic melamine sponges by in situ deposition of PDA coatings and Fe3O4 nanoparticles, followed by surface silanization with low surface energy 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PTOS) layer. The prepared melamine sponge composite (PTOS-Fe3O4@PDA/MF) not only exhibits a very high water contact angle of 165 +/- 1.5 degrees and an excellent ability to uptake a variety of oils and organic solvents (e.g. up to 141.1 g/g for chloroform), but also shows robust durability and superior recyclability. The PTOS-Fe3O4@PDA/MF sponge can also efficiently separate oils (or organic solvents) and water, as demonstrated by different model systems including immiscible oil-water solution mixture and miscible water-oil (W/O) emulsion (stabilized by surfactants). Furthermore, the PTOS-Fe3O4@PDA/MF sponge is able to in situ recover organics from water using a peristaltic pump, which gives it significant advantages over other traditional batch processes for oil-water separation. We believe that the PTOS-Fe3O4@PDA/MF sponge provides a very promising material solution to address oil-water separation, especially for the large-scale problems that have been long-time challenges with conventional sorption methods.

Automated summary

A magnetic-responsive superhydrophobic melamine sponge has been developed with high water contact angle, excellent oil absorption capacity, durability, and recyclability. This sponge can efficiently separate oils and water, and recover organics from water using a pump.