PAN-PVDF BLEND ULTRAFILTRATION MEMBRANES: PREPARATION, CHARACTERIZATION and PERFORMANCE EVALUATION

Abstract

In the arena of membranes the polymers like Polyacrylonitrile (PAN) and Poly (vinylidene fluoride) (PVDF)
material are mostly used for ultrafiltration (UF) applications. In this study we have prepared virgin
PAN/PVDF and PAN-PVDF blend UF membrane by phase inversion method. The prepared UF membranes
were characterized by their pore size (SEM and AFM), molecular weight cut-off (MWCO), surface
hydrophilicity (contact angle), surface potential (zeta potential) and mechanical properties. Membrane
performance was studied in terms of pure water flux and fouling characteristics were also evaluated. The
properties of the blend membranes are greatly influence by the relative proportion of PAN and PVDF in the
blend. It is observed that the blend membranes exhibited better wetting properties (Surface hydrophilicity)
compared to virgin PVDF membranes. PVDF membranes exhibited the highest surface roughness among all
the membranes. With increasing PAN content the blend morphology transform from dense macrovoid
pattern to finger like structure. The membrane M4 (30:70 PAN: PVDF) exhibited highest flux recovery ratio
of 87 % among all the virgin and blend membranes with a reasonable mechanical strength (28.8 % higher
than the virgin PAN membrane) and has pure water flux of 180 LMH at 50 psi pressure.