Preparation and characterization of an antifouling poly (phenyl sulfone) ultrafiltration membrane by vapor-induced phase separation technique

In this paper, anti-fouling poly (phenyl sulfone) ultrafiltration membranes were fabricated through the NIPS (V-0) and VIPS-NIPS (V-15 through V-60) technique. The effect of VIPS conditions on the structure and performance of the membranes has been investigated. Scanning electron microscopy (SEM) and liquid-liquid displacement porosimetry (LLDP) methods were used for membrane characterization. Pure water flux and BSA retention were also used for evaluation of separation performance of the fabricated membranes. The results revealed that by increasing VIPS time, pore size and permeate flux of the membranes were both increased except for V-30 membrane where both the pore size and PWF were decreased. BSA retention has an opposite behavior. By increasing VIPS time from 0 to 15 s, the PWF increased from 17.12 to 20.79 L/m(2) .h. At a VIPS time of 30 s, PWF reduced to 15.60 L/m(2).h, and by further increase of VIPS time to 60 s, the flux increased to 37.69 L/m(2).h. BSA retention showed a closer dependency to pore size of the membranes i.e. it decreased from 71.32% to 55.68% by increasing VIPS time from 0 to 15 s, then increased to 63.27% for V-30 membrane, and finally decreased to 52.69% at a VIPS of 60 s. It is noteworthy that the increase of VIPS time from 0 to 15 s leads to an increase in mean pore radius from 0.96 to 1.44 nm and then a decreases to 1.04 nm for a VIPS time of 30 s and finally to 1.39 nm with an increase of VIPS time to 60 s.