Janus Polyacrylonitrile/Carbon Nanotube Nanofiber Membranes for Oil/Water Separation

Abstract

Oil pollution has always been an important issue affecting the ecological and residential environment, and the development of a highly efficient oil/water separation membrane has become a hot topic. In this paper, Janus polyacrylonitrile (PAN) nanofiber membranes (PNM) were prepared by coblending hydrophilic SiO 2 nanoparticles, carbon nanotubes (CNTs) doped with PAN (PNM-SiO 2 and PNM-CNT, respectively) and then using sequential multilayer electrospinning. The existence of electrostatic mutual gravitational force between SiO 2 and CNTs makes the binding between the multilayer membranes exist more firmly, which is conducive to withstand the osmotic pressure brought by the liquid. In addition, Janus PAN membranes have different wetting properties; they have a micro/ nanopore structure that forms a permeable channel for liquids, thus enabling efficient separation of water-in-oil and oil-in-water emulsions, which separates oil/water emulsions with flux as high as 2188 L m −2 h −1 and separation efficiency as high as 99.8%. This experiment further develops the application of Janus membranes in oil/water separation.

Designing Janus Two-Dimensional Porous Materials for Unidirectional Transport: Principles, Applications, and Challenges

“…The fabrication of hydrophobic nanofibers typically involves the use of materials such as polyurethane, poly(methyl methacrylate), poly(vinylidene fluoride), and poly(vinylidene fluoride- co -hexafluoropropylene) . On the other hand, polymers commonly employed in the production of hydrophilic nanofibers include polyacrylonitrile , and cross-linked poly(vinyl alcohol) . The introduction of hierarchical nanostructures has been demonstrated to enhance both hydrophilicity and hydrophobicity.…”

Separation and Photodegradation of Dye-Containing Oil/Water Mixtures with a Photothermally Responsive PNIPAm-MXene/PAN-PNIPAm Nanofibrous Hydrogel Membrane

“…The ever-increasing discharge of industrial oily wastewater has caused extensive damage to the ecological balance and public health in recent years. − Oily wastewaters generally contain complicated compositions, such as oil/water emulsions, oil/water multiphase mixtures, or even highly toxic oily/aqueous-soluble dyes, which pose a greater health risk. Membrane separation technology has been widely used in wastewater purification due to its low consumption, high separation efficiency, and convenient operation features. − However, traditional separation membranes have poor antifouling performance, resulting in oil droplets or organic dyes in wastewater being easily adhered to the surface of the separation membrane, further blocking the pores during the separation process. Special wettability-oriented separation materials, such as superhydrophilic/underwater superoleophobic and superhydrophobic/superoleophilic materials, show great advantages in fouling resistance over traditional separation methods. − In addition, loading photocatalysts on the separation membrane is also an effective method to photodegrade organic dyes and avoid toxic dye contaminants blocking the pores of the separation membrane .…”

Recent advances in membrane technologies applied in oil–water separation

“…Polymer membranes are commonly used in membrane separation technology due to their high selectivity, ease of control, and uniform structure [14][15][16]. According to the polymer materials, the polymer membranes can be divided into polyamide (PA) membranes [17], polysulfone (PSU) membranes [18], polyvinylidene fluoride (PVDF) membranes [19], polyethersulfone (PES) membranes [20] and polyacrylonitrile (PAN) membranes [21]. Inorganic membranes have a wide range of applications in the field of membrane separation due to their high temperature stability, chemical inertness, and resistance to contamination [22][23][24].…”