Pre-oxidized PAN/PVP nanofibrous membranes with enhanced mechanical robustness and chemical stability for high-flux separation of oily wastewater from petroleum production

Discharge of oily wastewater, generated from oil and gas production can lead to severe marine and soil contamination, posing long-term threats to ecosystems and water security. Therefore, developing environmentally sustainable, high-flux, and chemically robust separation membranes is crucial for green petroleum production and water reuse. In this work, pre-oxidized polyacrylonitrile/polyvinylpyrrolidone (p-PAN/PVP) nanofibrous membrane has been fabricated to address this challenge aforementioned. The PVP, during pre-oxidation, formed cross-linked junctions, reinforcing the mechanical stability and the resistance to harsh chemical conditions. Additionally, our membrane also exhibited superhydrophilicity in air, underwater super-oleophobicity, low oil adhesion, ultrahigh flux (>8500 L·m−2·h−1·bar−1), and >99.8% separation efficiency for both crude-oil-in-water and surfactant-stabilized emulsions. More importantly, the p-PAN/PVP membrane could maintain integrity and wettability under acidic, alkaline, and high-salinity environments (1 M HCl, 1 M NaOH, 10 wt% NaCl) as well as in organic solvents (N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, etc). Our study provides a sustainable strategy to protect vulnerable ecosystems and promote cleaner energy development.