Effect of membrane surface characterization on salt and water transport through aromatic polyamide membranes

The effect of membrane surface characterization on the transport of salt and water through three types of commercial aromatic polyamide thin film composite membranes (i.e., LE, XLE and NF90, Filmtec) is investigated. The transport of salt and water through membranes is studied by osmosis process. The surface characterization (roughness, crosslinking density and zeta potential) of the membranes is analyzed by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and streaming potential measurements. The results show that the influence of membrane surface characterization on the transport of salt is more evident than that of water. The transport rates of both salt and water increase with the decrease of roughness, crosslinking density as well as zeta potential. Moreover, roughness plays the most important role on the transport process in our research range. These observations can provide important information on the design and improvement of aromatic polyamide membranes.