Table Salt as a Template to Prepare Reusable Porous PVDF-MWCNT Foam for Separation of Immiscible Oils/Organic Solvents and Corrosive Aqueous Solutions

Many advanced materials are designed for separation of immiscible oils/organic solvents and aqueous solutions, including poly(vinylidene fluoride) (PVDF)-based materials with superwettability. However, due to the limited solubility of PVDF, techniques (e.g., phase inversion and electrospinning) often involve the use of toxic organic solvents. Here a facile organic solvent-free method is described to prepare a porous PVDF-MWCNT (multiwalled carbon nanotube) foam using table salt as a sacrificial template. The porous PVDF-MWCNT foam is characterized as superhydrophobic-superoleophilic with good elasticity due to its 3D porosity and low surface energy. The foam exhibits high adsorption capacity to a variety of oils/organic solvents and can be easily reused by squeezing, heating, or releasing in other solvents. Moreover, the foam is highly resistant toward UV exposure, corrosive aqueous solutions such as acidic, alkaline, salty solutions, and turbulent environments, and shows effective oils/organic solvents removal in these complex environments. The continuous separation of immiscible oils/organic solvents and corrosive aqueous solutions with vacuum assistance is also presented. The organic solvent-free and reusable PVDF-MWCNT foam is a promising candidate for large-scale industrial separation of oils/organic solvents and water in corrosive and turbulent conditions.