Tailoring structures and performance of polyamide thin film composite (PA-TFC) desalination membranes via sublayers adjustment-a review

Polyamide thin film composite (PA-TFC) membranes are finding more and more popularity in desalination via both reverse osmosis (RO) and forward osmosis (FO) process, which can effectively alleviate worldwide freshwater crisis through translating seawater into potable water. Despite of huge progresses, great challenges still exist in trade-off between water flux and salt rejections, surface fouling, chlorination, and concentration polarization. This has encouraged tremendous research in tailoring structures and properties of virgin PA-TFC membranes. Nevertheless, it seems that major research has focused on the surface polyamide layer. It should be noticed that sublayer also significantly affect the PA-TFC membranes. Fortunately, researchers have realized this fact in recent years and have done some important and meaningful work. From this point of view, this paper reviews and discusses the state-of-the-art developments on achievements of sublayers adjustment for tailoring PA-TFC membranes used in RO and FO desalination. Traditional sublayers adjustment and novel electrospun nanofibrous membranes (ENMs) sublayers are highlighted. It also provides an insight for future research directions combined with comments and perspectives. It is sincerely expected that this review paper can provide some clues for further in-depth evaluation and research in exploring more advanced PA-TFC membranes by adjusting sublayers.