Figure 4: Up image shows SEM images of cross-section of M0 UF membrane fabricated by phase inversion method. It can be seen that the fabricated membranes have the morphology with clear asymmetric pores.SEM images of pristine PSf membrane (M0) (a), after grafting with PAA in 15 min (M-1) (b), and 30 min (M-4) (c).