Ultra-high flux electrospun PAN/MWCNTs/SiO2 membranes for oil–water separation: development and characterization

Oily wastewater is inevitably generated during the development and production of oil fields. This type of wastewater contains a significant amount of toxic and harmful pollutants. If not effectively treated and properly discharged, it can cause severe environmental pollution. Oil–water separation is a critical prerequisite for the effective treatment of oily wastewater; however, developing separation materials with high throughput and excellent mechanical properties remains a significant challenge. In this study, MWCNTs/SiO₂ membranes were prepared using nano-SiO₂ and multi-walled carbon nanotubes (MWCNTs) as matrices via electrospinning technology. Here, we show that when the mass ratio of SiO₂ to MWCNTs is 1:0.8, the MWCNTs/SiO₂ membrane exhibits optimal oil–water separation performance, with an oil retention rate exceeding 98%, and stable filtration performance over more than 10 cycles. This performance enhancement is attributed to the dual synergistic hydrophilic effect of acid-modified CNTs and silica, which significantly improves water permeability. Additionally, the innovative design of the secondary electrostatic spraying process enhances the structural strength of the film. The mechanical stability and high-temperature resistance of MWCNTs/SiO₂ membrane prepared in this study greatly surpass those of commercial PAN fiber membranes, demonstrating its potential for oil–water separation applications.

Graphical abstract