Investigation of the effect of coagulation bath composition on PVDF/CA membrane by evaluating critical flux and antifouling properties in lab-scale submerged MBR

摘要

Ultrafiltration membranes were prepared from blends of poly(vinylidene fluoride) (PVDF)/cellulose acetate (CA) via phase inversion method. The effect of different coagulation bath compositions on the morphology and performance of the blend membrane prepared from casting solution of PVDF/CA with ratio of 80/20 was investigated using sewage wastewater. NaCl and ethanol were used as additives of coagulation bath. Fouling analysis was conducted with Bovine Serum Albumin solution and critical flux evaluation was performed using a lab-scale membrane bioreactor. In terms of morphological structure, the macrovoids decreased and changed to finger-like structure. The irreversible fouling reduced and the flux recovery ratio (FRR) of the modified membranes increased remarkably while the reversible fouling caused by deposition of foulants on the surface of the membranes increased. The maximum values of FRR and critical flux of irreversibility were reached by the membrane which was prepared in the coagulation bath containing the highest concentration of NaCl.