Mussel and fish scale-inspired underwater superoleophobic kapok membranes for continuous and simultaneous removal of insoluble oils and soluble dyes in water

Abstract

Bioinspired materials with special wettability towards water and oils have been proven very efficient in removal of insoluble organic pollutants in water. However, these materials cannot remove water-soluble organic contaminants, and often have some problems such as easy contamination by oils, low water tolerance and complicated preparation methods. Herein, we present a simple approach for the fabrication of mussel and fish scale-inspired underwater superoleophobic kapok membranes via treatment of natural kapok fibers with sodium chlorite, surface modification with polydopamine, and then filtered to yield membranes. SC treatment and PDA modification not only make the membranes underwater superoleophobic with high contact angles and low sliding angles for oils, but also introduce abundant N and O-containing groups. The kapok membranes feature excellent underwater superoleophobicity, high adsorption properties for water-soluble dyes, and high stability and flexibility. Furthermore, continuous and simultaneous removal of many kinds of insoluble oils and soluble dyes in water was achieved with very high removal efficiencies in a short time by simply passing through these membranes. We believe that the underwater superoleophobic kapok membranes are very promising for removal of organic pollutants in water.