Nanosheet alpha-Co(OH)(2) composite membranes with ultrathin separation layer for removing dyes from solvent with high flux

Organic solvent nanofiltration (OSN) is one of the fast development areas of membrane separation. The nano filtration performances of membranes are mainly depended on the thickness of separation layers and the orientation of separation channels. Herein, an ultrathin alpha-Co(OH)(2) film was fabricated through the in situ growth of alpha-Co(OH)(2) nanosheets on alumina tubular substrate for OSN. The thickness of the film was approximately 300 nm and the alpha-Co(OH)(2) nanosheets were vertically grown to leave channels perpendicular to the substrate. The orientation growth and interlayer gallery of the alpha-Co(OH)(2) layer were confirmed by SEM, PXRD and SAXS characterization. The resulting composite membrane exhibits high fluxes for organic solvents. Particularly, in separating eriochrome black T from methanol solution, the permeance could reach 127 L m(-2) h(-1) bar(-1). We anticipate that the facile fabrication method and excellent separation performances make the alpha-Co(OH)(2) composite membrane have a great application potential in OSN.