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

Abstract

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. More over, the foam is highly resistant toward UV exposure, corrosive aqueous solutions such as acidic, alkaline, salty solutions, and turbulent environ ments, 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.

Preparation of Fouling-Resistant Nanofibrous Composite Membranes for Separation of Oily Wastewater

“…It can be concluded that the TiO 2 grafted to the hydrophilic membrane surface prevented direct adhesion of the oil droplets. Chen et al [54] prepared a porous PVDF-MWCNT (multiwalled carbon nanotube) foam, which was characterized as a reusable and compressible superhydrophobic-superoleophilic separator with good elasticity and low surface energy. The porous PVDF-MWCNT foam exhibited high adsorption capacity to a variety of oils/organic solvents that made it a promising candidate for large-scale industrial applications.…”

“…It can be concluded that the TiO2 grafted to the hydrophilic membrane surface prevented direct adhesion of the oil droplets. Chen et al [54] prepared a porous PVDF-MWCNT (multiwalled carbon nanotube) foam, which was characterized as a reusable and Figure 9. FTIR spectra of the neat sample and the sample after modification.…”

“…It can be concluded that the TiO2 grafted to the hydrophilic membrane surface prevented direct adhesion of the oil droplets. Chen et al [54] prepared a porous PVDF-MWCNT (multiwalled carbon nanotube) foam, which was characterized as a reusable and The FTIR spectra were collected in order to investigate the chemical structure of the pristine membrane, and the membrane after plasma and chemical modification. Figure 9 confirms the presence of both polymers in the blend of PVDF/PAN.…”

Recent Advances in Robust Superwettable Membranes for Oil–Water Separation

“…Finally, although the abovementioned testing strategies are based on measuring contact angles (Figure a,b) or measuring the change in oil–water (non‐corrosive) separation performance after corrosion (Figure c), which reflect chemical resistance, the practical separation of a variety of complex oil–water mixtures composed of corrosive solutions or organic solvents to imitate real harsh conditions also makes sense (Figure d). Several separation systems especially for corrosive water–oil mixtures, water–organic solvents mixtures, and corrosive water–organic solvents mixtures have been established.…”

Tunable polarization components and electric field induced crystallization in polyvinylidenefluoride: A piezo polymer

“…There have been ample studies on PVDF, its copolymers and nanocomposites, focussing the structure and multifunctional property . PVDF is known to stabilize in five distinct crystalline phases related to different chain conformations α, β, γ, δ, and ε, in which the most investigated phases are α, β, γ . β‐phase commonly known as phase I exhibits superior piezoelectric properties due to its non‐centrosymmetric crystalline state with the dipole moment of two chains containing CF and CH in the unit cell adding up resulting in a net dipole moment perpendicular to the carbon backbone with fluorine and hydrogen as the negative and positive poles, respectively …”