Preparation of blend hydrophilic PSF-SPEEK ultrafiltration membranes for oily wastewater treatment

Membrane separation is known as an efficient technique for the oily wastewater treatment. Therefore, in the present study, sulfonated poly (ether ether ketone) (SPEEK) was introduced into the polysulfone (PSF) solution in order to enhance the hydrophilicity and the membrane structure for the oil–water separation. The hollow fiber membranes were fabricated via a phase-inversion process. The membranes were characterized by a N2 permeation test, overall porosity, water contact angle, pure water flux and scanning electron microscopy (SEM) analysis. The blend PSF-SPEEK membrane presented an open finger-like morphology with a thicker outer skin layer and smaller pore sizes. The blend membrane showed overall porosity of 78.8% due to the open structure. The outer surface water contact angle of the blend membrane decreased approximately 8º due to the hydrophilic nature of SPEEK. The blend membrane showed N2 permeance of 134 GPU and mean pore size of 22 nm. Improved pure water flux of 9.3 L/m2 h at 400 kPa and the small resistance of 0.483 m2 h bar/L for the blend membrane were related to the higher hydrophilicity and the open structure. The blend membrane showed the oil rejection of over 98% and the stable water flux of 6.5 L/m2 h due to the improved structure.