Effects of zinc oxide Nanospheres on the Separation performance of Hollow fiber poly(piperazine-amide) composite nanofiltration membranes

Abstract

The inner-skinned hollow fiber composite (HFC) nanofiltration (NF) membranes were modified through the incorporation of zinc oxide nanospheres in the poly(piperazine amide) layer during the interfacial polymerization (IP) process. The active layer was coated on the inner surface of polysulfone (PSF) support membrane via Two-way coating technique. The chemical composition and morphology of HFC membrane surface were evaluated through the Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) and Scanning Electronic Microscopy (SEM). The effects of zinc oxide (ZnO) nanospheres on membrane performance including the hydrophilicity, separation performance and chlorine resistance were investigated. The results showed that the modified HFC membranes with low concentration ZnO nanospheres (1.5 wt%) had an improved flux (33.8 L·m-2·h-1) meanwhile the salt rejection of MgSO4 was well maintained (92.2 %) at 0.7 MPa. The introduction of ZnO also dramatically enhanced the chloride resistance of composite NF membranes in comparison with the control membranes prepared without ZnO. Therefore, nano metallic oxide like ZnO could be considered as a potential modifier to improve the performance of HFC nanofiltration membranes.