Pre-oxidized PAN Nanofibrous Membrane to Efficiently and Continuously Separate Large-Scale Viscous Oil-in-Water Emulsions Under Harsh Conditions with Ultra-Long-Term Oil-Fouling Recovery

High-performance multifunctional filtration membranes are highly required in treating practically complex oily wastewater systems, but still a challenge unsolved. Herein, we propose a facile route to address these challenges simultaneously by simply constructing electrospun pre-oxidized polyacrylonitrile nanofibrous membrane (p-PAN NM). Given the pre-oxidation process, the p-PAN NM displays not only robust anti-corrosive tolerance against diverse corrosive media, but also superhydrophilicity/underwater superoleophobicity. Additionally, ~ 99% separation efficiency, ~ 100% oil-fouling recovery, and ultra-long service life (up to 265 h) have been realized in separating large-scale surfactant stabilized soybean/crude oil-in-water emulsions. Furthermore, strong anti-corrosive performance against various corrosive media (e.g., 1 M HCl, 1 M NaOH, or 10 wt% NaCl) has been achieved as well. Spin-unrestricted density functional theory (DFT) computations implemented in the Dmol3 modulus has been conducted to understand the robust fouling recovery and the variation of surficial wettability after pre-oxidation. These outstanding filtration functions make our NM hold great potential in separating viscous oil/water emulsions under harsh conditions.

Graphical Abstract