Preparation and properties of polyvinyl chloride ultrafiltration membranes blended with functionalized multi‐walled carbon nanotubes and MWCNTs/Fe3O4 hybrids

To investigate the influence of magnetic materials combined with carbon nanotubes (CNTs) as fillers on the membrane properties, multi-walled carbon nanotubes (MWCNTs) functionalized by mixed acids (VH2SO4:VHNO3=3:1) were loaded by Fe3O4 through a hydrothermal method. The obtained MWCNTs/Fe3O4 hybrids were characterized by X-ray diffraction (XRD), Infrared spectroscopy (IR) spectrum, and scanning electron microscope (SEM) and then blended with polyvinyl chloride (PVC) to prepare ultrafiltration (UF) membranes through a phase inversion process. Simultaneously, two other UF membranes, PVC blended with acid-treated MWCNTs and PVC blended with nothing, were also prepared. The results showed that the membrane porosity and mean pore size increased slightly with the addition of fillers. Static contact angle showed that MWCNTs/Fe3O4 hybrids improved the hydrophilicity of membrane surface better than the acid-treated MWCNTs. Pure water flux increased consistently with the hydrophilicity of the membrane surface. SEM and atomic force microscope (AFM) images showed that the MWCNTs/Fe3O4 blended membrane formed a relatively complete pore structure throughout the cross-section and had a rougher top surface. However, the mechanical properties of membranes with fillers were reduced compared with the pristine PVC membrane. The rejections of membranes for Bovine serum albumin (BSA), Bisphenol A (BPA), and Norfloxacin (NOR) showed that MWCNTs/Fe3O4 played an important role in trapping pollutants in membrane filtration. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43417.