Scalable manufacturing of nonflammable bioinspired superhydrophobic sponge for oily wastewater treatment via water-based strategy

Developing a water-based methodology for scalable-manufacturing the versatile sponge materials, is meaningful but highly challenging. In this work, a superhydrophobic sponge was constructed via a simple and green strategy, which contained melamine sponge (MS) substrate, polydopamine (PDA) and hydrophobic SiO2 (HSiO2). Prominently, the aqueous solvent is harmless to the various sponge materials, in which superhydrophobic HSiO2-PDA@MS (SPMS) inherited the nature of MS, including excellent oil-uptake (67.6–139.1 times of its weight), superior mechanical property, porous structure and flame retardancy. The layer of HSiO2/PDA not only endowed the SPMS selective sorption ability, but also showed a good interfacial compatible to further improve the flame-retardant property for MS or ignitable polymer sponge. Thus, SPMS exhibited a good adaptability in fire, could significantly reduce the fire risks in oil spill accident and achieve the fire-off through a simple press procedure. Moreover, the compressed SPMS showed the satisfactory separation efficiency (over 99 %) for surfactant-stable O/W emulsions, even in separating complex O/W emulsions (SE over 96 %). And this sponge displayed excellent robust durability, outstanding recyclability. Given about all, this work provides a novel inspired insight for the large-scale design of multifunctional sponge material for oily wastewater treatment.