Study on the interfacial bonding state and fouling phenomena of polyvinylidene fluoride matrix-reinforced hollow fiber membranes during microfiltration

Abstract

Reinforced polyvinylidene fluoride (PVDF) and polyacrylonitrile (PAN) hollow fiber membranes were prepared through dry–wet spinning process and included PVDF or PAN polymer solutions (coating layer) and matrix PVDF membrane. The performance of the membranes varies with different polymer solutions and is characterized in terms of ink solution and activated sludge flux, dynamic mechanical analysis (DMA), mean pore size, a mechanical strength test, and morphology observations by a scanning electron microscope (SEM). The results of this study indicate that PAN coating layer is easy to peel off from the matrix membrane. Interfacial bonding strength is also detected by dynamic mechanical analysis indirectly. The reinforced membranes show a narrower pore size distribution and smaller mean pore size than the matrix membrane. The elongation at break increases much more and the membranes are endowed with better flexibility performance. The homogeneous-reinforced (HMR) and heterogeneous-reinforced (HTR) membranes have a lower rate of flux decline compared with matrix membrane during ink solution filtration. The main types of all membranes fouling in microfiltration of ink solution were attributed to initial pore blocking followed by cake formation. Then, in the activated sludge solution, the reinforced membranes have stable efficiency in antifouling property for the real MBR system.