Carbonaceous microsphere/nanofiber composite superhydrophilic membrane with enhanced anti-adhesion property towards oil and anionic surfactant: Membrane fabrication and applications

Abstract

Fouling issue is the key obstacle that limited the practical applications of superwetting oil/water separation membrane. Dispersed oil phase and soluble surfactants in the emulsion are the primary foulants during separation of oil/water mixtures. Therefore, developing membranes with anti-adhesion property towards both dispersed phase and surfactant is of great importance. In this study, a superhydrophilic, underwater superoleophobic composite membrane with excellent antifouling property for separating oil-in-water emulsions stabilized by anionic surfactants was fabricated. Briefly, carboxylated carbonaceous microspheres were synthesized and loaded on nanofibrous membrane through a facile hydrothermal strategy. Acrylic acid was introduced to the hydrothermal process to manipulate the surface charge of carbonaceous microspheres. The fabricated membrane showed excellent anti-adhesion property towards dispersed phase (toluene) due to the improved surface wettability and hydration property. Underwater oil contact angle was up to 160 ± 1° (e.g., M8-2 membrane). Meanwhile, the fabricated membrane exhibited excellent anti-adhesion performance for oil-in-water emulsions stabilized by anionic surfactants (e.g. sodium laurylsulfonate) due to electrostatic repulsion. Therefore, the membrane can maintain the permeability as high as 41,020 ± 805 L m-2 h-1 bar−1 even after ten times of usage. The construction strategy and the antifouling analysis presented in the current study may give more opportunities for the understanding of superwetting oil/water separation process.