Dual-functional membrane decorated with flower-like metal-organic frameworks for highly efficient removal of insoluble emulsified oils and soluble dyes

High-performance membranes for simultaneously removing insoluble emulsified oils and soluble organic dyes are in urgently demand for industrial wastewater treatment, but are strictly limited by the single-function and serious fouling problem. Herein, a dual-functional membrane with excellent antifouling ability for efficiently dye/oil/water emulsion separation has been fabricated by growing flower-like metal-organic frameworks (MIL-53-OH) on polyacrylonitrile/polyethyleneimine membrane for the first time. The synergistic effect of the hierarchical flower-like structure and superhydrophilic compositions with high hydration ability endows the obtained membrane with a stable and ultra-strong oil-repelling hydration layer, thus imparting the membrane formidable oil resistance and exceptional oil/water emulsion separation performance (permeate flux > 4000 L m(-2) h(-1)). What's more, the superhydrophilic compositions render the membrane an excellent dye remove capacity by electrostatic forces and hydrogen bonding. The membrane rejections for dyes and emulsified oils are above 99%, and the dyes and oils on the used membrane can be easily washed away with methanol and water, respectively, confirming that the membrane has desirable recyclability. Besides, the membrane possesses excellent mechanical performance and outstanding acid and alkali resistance, indicating that the membrane is a promising candidate for removing insoluble emulsified oils and soluble dyes.

Automated summary

A dual-functional membrane with excellent antifouling ability has been fabricated by growing flower-like metal-organic frameworks, enabling efficient dye/oil/water emulsion separation. The synergistic effect of the hierarchical flower-like structure and superhydrophilic compositions endows the membrane with stable and ultra-strong oil-repelling hydration layer, providing exceptional oil/water emulsion separation performance. The membrane also shows excellent dye removal capacity and desirable recyclability, making it a promising candidate for industrial wastewater treatment.