Preparation and characterization of novel thin film composite nanofiltration membrane with PVDF tree-like nanofiber membrane as composite scaffold
Feng Liu, Lanlan Wang, Dawei Li, Qingsheng Liu, Bingyao Deng
Abstract
In the field of seawater and waste water purification, thin film composite membranes (TFC) have drawn great attention. In this study, a novel TFC membrane was fabricated based on the layer of polyvinylidene fluoride (PVDF) via a one-step process formed tree-like electrospun nanofiber membranes (TENMs). Compared with conventional support membrane, TENMs possessed high surface porosity, low tortuosity, high-proportioned interconnect pore, and minimum average pore size below 200 nm. Therefore, it has great potential in the preparation of high-performance TFC nanofiltration(NF)membrane. The effect of additive Tetrabutylammonium chloride (TBAC) concentration in the morphology and structure of TENMs was also discussed. Results indicated that adding 0.025 mol TBAC in the spinning solution would facilitate the formation of tree-like structure with the smallest pore size of 130–140 nm and narrowest pore diameter distribution, as well as the densely packed branching nanofibers. Furthermore, the effect of TENMs structure and surface morphology on the formation of polyamide film were also studied. It was found that the ultrafine branches embedded into polyamide matrix formed “directed water channels”, which increased water molecules transporting speed. Rejection test revealed that a rejection rate above 97% against MgSO4 solution and 76% against NaCl solution could be achieved, indicating the potential in the application of water purification.