Microstructure–performance relationships of hollow‐fiber membranes with highly efficient separation of oil‐in‐water emulsions

Abstract

The critical breakthrough pressure related to the membrane surface wettability and pore size is a key parameter determining membrane performance in particular applications, such as oil-water mixture separations. A series of hydrophilic polysulfone hollowfiber membranes with different pore sizes were prepared and characterized to evaluate the separation performance of oil-in-water emulsions and to develop an optimum membrane for such emulsions. For the optimum membrane, the absolute value for the cosine of the surface oil droplet contact angle (0.72) was close to the ratio of the outer surface pore size to the oil droplet size (0.71); it was also similar to the absolute value of the cosine of the underwater oil contact angle on the polysulfone material (0.65). From the point of view of the surface wettability, theoretical calculations were performed to select a suitable membrane with the aim of reaching the maximum efficiency in practical oil-water mixture separation.

Beyond Superwetting Surfaces: Dual-Scale Hyperporous Membrane with Rational Wettability for “Nonfouling” Emulsion Separation via Coalescence Demulsification

“…The theoretical critical break through pressure (ΔP b ) was calculated to be 2.3 bar according to the following eq : where γ is the water–oil interfacial tension (35 mN m –1 for water and toluene), θ is the underwater oil contact angle on the membrane surface (174°, as shown in Figure ,) and r is the maximum membrane pore radius (0.3 μm). However, the presence of a surfactant would reduce the interfacial tension between water and toluene, which therefore caused a reduced critical pressure. In this case, toluene droplets were able to pass through the membrane at 1.0 bar with the aid of surfactants.…”

Nonswelling Silica–Poly(acrylic acid) Composite for Efficient and Simultaneous Removal of Cationic Dye, Heavy Metal, and Surfactant-Stabilized Emulsion from Wastewater

“…The treatment of emulsion wastewater is an intractable problem that needs to be solved immediately. Several methods and materials have been developed for emulsion separation. − The as-prepared SiO 2 –PAA possesses the attractive property to separate cationic surfactant-stabilized emulsions. To study the separation property of emulsions, 20.0 mg of SiO 2 –PAA was added into 50 mL of CTAB-stabilized dodecane-in-water emulsion at 25 °C.…”

Preparation of fiber core support UHMWPE/SiO2 composite hollow fiber membrane toward enhancing structure stability and antifouling

“…[1] Wastewater treatment is an important method to solve the shortage of water resources. [2][3][4][5] Membrane separation technology is widely used in water treatment because of its simple process, convenient operation, and low energy consumption. [6][7][8] There are many materials used in membrane separation technology.…”