Photothermal-Responsive Single-Walled Carbon Nanotube-Based Ultrathin Membranes for On/Off Switchable Separation of Oil-in-Water Nanoemulsions

Abstract

Oil-contaminated wastewater threatens our environment and health, especially that stabilized by surfactants. Conventional separation protocols become invalid for those surfactant-stabilized nanoemulsions due to their nanometer-sized droplets and extremely high stability. In this paper, photothermal-responsive ultrathin Au nanorods/poly(N-isopropylacrylamide-co-acrylamide) cohybrid single-walled carbon nanotube (SWCNT) nanoporous membranes are constructed. Such membranes are capable of separating oil-in-water nanoemulsions with a maximum flux up to 35 890 m(2)·h(-1)·bar(-1) because they feature hydrophilicity, underwater oleophobicity, and nanometer pore sizes. It is remarkable that the permeation flux can be simply modulated by light illumination during the process of separation, due to the incorporation of thermal-responsive copolymers and Au nanorods. Meanwhile, it shows ultrahigh separation efficiency (>99.99%) and desired antifouling and recyclability properties. We anticipate that our ultrathin photothermal-responsive SWCNT-based membranes provide potential for the generation of point-of-use water treatment devices.