Preparation of Blend Hydrophilic Polyetherimide-Cellulose Acetate Hollow Fiber Membrane for Oily Wastewater Treatment

Membrane separation is known as an efficient technique for oily wastewater treatment. In the present study, cellulose acetate (CA) was introduced into the polyetherimide (PEI) solution in order to enhance hydrophilicity and the membrane structure for oil–water separation. The hollow fiber membranes were prepared via a phase-inversion process. The membranes were characterized by N_2 permeation test, water contact angle, pure water flux and field emission scanning electron microscopy (FESEM). The blend PEI-CA membrane presented larger finger-likes morphology with a thicker outer skin layer. From N_2 permeation test, the blend membrane showed effective surface porosity of 697 m^-1 and mean pore size of 4.5 nm. The higher water flux and lower resistance of the blend PEI-CA membrane were related to the higher hydrophilicity and the open structure. Due to small pore sizes and enhanced hydrophilicity, the blend membrane showed a stable oil rejection of over 98% and water flux of 18 L/m^2 h after 100 min of the separation operation. The developed PEI-CA membrane can potentially be applied in petrochemical and refinery industries for oily wastewater treatment.