Hydrophilic nanofibrous composite membrane prepared by melt-blending extrusion for effective separation of oil/water emulsion

A polyethylene-co-polyvinyl alcohol (EVOH) nanofiber membrane was prepared by the melt blending extrusion and high-speed airflow deposition process. Then nano cellulose crystal/polyethylene-co-polyvinyl alcohol (NCC/EVOH) nanofiber composite membranes were obtained via coating and depositing the barrier layer on the surface of the nanofiber membrane. The basic structural properties and oil-water separation performance of the composite membranes were investigated. The results show that the deposited NCC formed a dense layer in the surface of the nanofiber membrane with smaller pore size, and had no effect on the continuous pore structure of the membrane. With increasing NCC content, the composite membranes showed an increase of tensile strength (from 9.969 MPa to 12.991 MPa) and a decrease of contact angle, pore size, and water flux. The water flux and the filtration flux of the composite membrane can be improved within a certain range by increasing the operating pressure. The NCC/EVOH nanofiber composite membranes were successfully applied for the separation of oilwater emulsion and exhibited a higher rejection rate (99.5%). Moreover, the NCC/EVOH nanofiber composite membranes possessed a higher recovery rate of filtration flux than unmodified EVOH nanofiber membranes and the commercial micro-filtration membranes.