Superhydrophobic/Superoleophilic Polyacrylonitrile/Ag Aerogels for the High Efficient Oil/Water Separation and Sensitive Detection of Low‐Concentration Oily Sudan Dyes

Abstract

The detection of low‐concentration oily pollutants, especially when in oil/water mixtures or real food matrix, still faces great challenges. Integrating adsorption and plasmonic hot‐spot on single material will be an efficient method for ultra‐sensitively detecting oily dyes or contaminants in oil/water mixtures via surface‐enhanced Raman scattering. Herein, the superhydrophobic/superoleophilic polyacrylonitrile (PAN)/Ag aerogels which can quickly absorb and detect low‐concentration oily dyes in oil/water mixtures are successfully fabricated. In order to solve the contradiction that abundant hydrophilic‐Ag nanoparticles are adverse to the superhydrophobicity of substrate but in favor of Raman signals, the superhydrophobic/superoleophilic PAN/Ag aerogels are prepared through two steps: substrate‐seeding and secondary‐growth. The lowest detection concentration of 10−12 m for oil‐soluble Sudan III in oil/water mixtures is achieved by using PAN/overgrown Ag (PAN/O‐Ag) nanofibrous aerogels as absorbent, which is superior to most of reported materials. Moreover, a detection limit of 0.1 ppm of Sudan III spiked in chilli powder is obtained using PAN/O‐Ag aerogels.

Multifunctional materials with controllable superwettability for oil–water separation and removal of pollutants: Design, emerging applications, and challenges

“…The superhydrophobic surface is the earliest and most widely used oil-water separation material, which can accomplish oil-water separation, and has an excellent performance in many other aspects, such as self-cleaning, anticorrosion, anti-fog, anti-icing, and others. [48] There are many types of SOL−SHB separation materials, such as porous metal meshes, [49] cellulose-based materials, [50] cotton-based materials, [51] polyvinylidene fluoride (PVDF) membranes, [52] organic membranes, [53] foams, [54][55][56] sponges, [57] aerogels, [58] zeolitic imidazolate framework-8 (ZIF-8), [59] and textile. [60] Oil will adhere to the surface of the SOL−SHB materials, resulting in separation difficulty due to the pores being clogged with oil.…”