Preparation and characterization of polycarbonate/thermoplastic polyurethane blend membranes for wastewater filtration

Abstract

The polycarbonate (PC)/thermoplastic polyurethane (TPU) blend membranes were prepared by phase inversion process applied to membrane bioreactor (MBR) to investigate the fouling characteristics. The impact of TPU and poly (vinylpyrrolidone) PVP concentration in polymer dopes on membrane structure, morphology, and performance were studied. The flat sheet fabricated membranes were characterized by scanning electron microscope (SEM), water contact angle (WCA), membrane surface roughness measurements and mechanical strength. The membrane performance was investigated at subcritical operating conditions. Pure water and critical flux through the fabricated membranes were measured for better understanding of the filtration and antifouling properties in MBR. The results showed that the membrane with polymer composition of 85/15 (PC/TPU) presented better performance in activated sludge throughout critical flux than that of other prepared membranes. Therefore, different dosages of PVP were introduced in this composition to study the effect of the additive in novel blend membranes. Likewise, the results indicated that TPU played the role of pore formation agent during the NIPS process, and the mean pore size of the membranes were increased with the increment in TPU content, which led to higher water flux. Finally, SEM images showed that the sponge-like structure formation was intensified by addition of TPU in casting solution. However, the finger-like structure was found to increase with introduction of 0.5wt.% PVP content into the casting solution. This study highlights the potential of PC membrane application in wastewater treatment with incorporation of TPU and PVP into PC membrane matrix.