Faveolate cell-engineered and multi-heterostructured flexible ceramic nanofibrous membranes with confined coalescent nanochannels enable sustainable oily water remediation

Abstract

Oily wastewater, resulting from oil recovery, petrochemical industries, or accidents, poses a significant threat to the aquatic environment. Membrane separation technology can offer unprecedented opportunities for highly efficient water remediation but at the cost of poor permeability and serious oil fouling. Here, we report a faveolate nanofibrous membrane through the steric growth of bismuth oxybromide-bismuth oxyiodide nanoflakes on the TiO2/polypyrrole nanofibers. The spatially faveolate cells create highly covered confined spaces that efficiently capture and coalesce nanosized oil droplets, thus achieving substantial selectivity for micron porous membranes. The faveolate membranes are capable of efficiently separating various oil-in-water emulsions, particularly nanoscale surfactant-stabilized emulsions with a high permeation flux of 6075 L m-2h−1 and a good separation efficiency of 99.95 %. Moreover, the membranes with multi-heterostructure act as efficient photocatalysts, giving rise to visible light-induced sufficient fouling-tolerant property with nearly zero irreversible oil fouling. This study could provide a novel strategy for developing a new generation of membranes with high performance and long service lifetime for oily sewage remediation.