Development of Janus Cellulose Acetate Fiber (CA) Membranes for Highly Efficient Oil-Water Separation.

A new type of Janus cellulose acetate (CA) fiber membrane was used to separate oil-water emulsions, which was prepared with plasma gas phase grafting by polymerizing octamethylcyclotetrasiloxane (D4) onto a CA fiber membrane prepared by centrifugal spinning. The Janus-CA fiber membrane was described in terms of chemical structure using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) analysis, energy dispersive X-ray spectroscopy (EDX) analysis and morphology by field emission scanning electron microscopy (FESEM). In this contribution, we examine the influence of spinning solution concentration, spinning speed and nozzle aperture on the centrifugal spinning process and the fiber morphology. Superhydrophobic/hydrophilic Janus-CA fiber membrane was used to separate water and 1,2-dibromoethane mixture and Toluene-in-water emulsion. Unidirectional water transfer Janus-CA fiber membrane was used to separate n-hexane and water mixture. The separation for the first-time interception rate was about 98.81%, 98.76% and 98.73%, respectively. Experimental results revealed that the Janus cellulose acetate (CA) fiber membrane gave a permeate flux of about 43.32, 331.72 and 275.27 L/(m2·h), respectively. The novel Janus-CA fiber membrane can potentially be used for sustainable W/O emulsion separation. We believe that this is a facile strategy for construction of filtration materials for practical oil-water separation.