A dual-layer membrane with antibacterial property for efficient purification of wastewater containing Congo red and oil-in-water emulsion

Abstract

It's urgent to prepare membranes which can treat wastewater containing complex contaminants. Herein we report a dual-layer membrane containing a topside Co-MOF/Co(OH)2 layer and a bottom PANI layer on the polyamide microfiltration substrate. The membrane could realize a rejection of over 99.6 % for diesel-in-water emulsion with the permeance around 50–100 L m−2 h−1 bar−1 within three one-hour separation rounds. Meanwhile, the membrane could also separate wastewater containing Congo red with the permeance of 300–500 L m−2 h−1 bar−1 and the rejection above 93 %. For complex wastewater containing diesel-in-water emulsion and CR, the membrane displayed satisfactory separation ability. Furthermore, the membrane displayed excellent antibacterial activity against both gram-negative E. coli and gram-positive S. aureus, which would help it to avoid fouling by bacteria during the separation. Our work effectively constructs a composite membrane, which provides an effective strategy for the treatment of water containing oil/water emulsions and dyes.