Graphene oxide (GO) has triggered significant attention as a new type of self-assembly membrane material. However, the low filtration flux and unstable performance of GO membrane limit its practical application. Hence, in this work, layered double hydroxides (LDHs), as a 2D material with double-layer channel structure and positive electricity, were self-assembled with GO at weight ratio of 7:3 by electrostatic interaction. Then, the GO/LDH hybrids combined with polydopamine (PDA) to obtain stable and high-flux GO-based membranes through vacuum filtration and the structure and morphology of as-prepared samples were characterized by FT-IR, XRD, XPS, and SEM. Furthermore, the separation performance and surface electronegativity of membranes were tested via pure water flux, rejection efficiency, recycle experiments, and zeta potential. Results revealed that the stability and flux of composite membrane were enhanced significantly compared with neat GO-based membrane. Further, the dye rejection rate of methylene blue (MB) is higher than Congo red (CR) and rhodamine B (Rh B) and reached to 99.8%.
A positively charged, composite, hollow-fiber nanofiltration (NF) membrane was fabricated by interfacial polymerization using polyethylenimine and trimesoyl chloride as reactive monomers. Rejection rates of different salts and dyes were measured by the NF membranes at various pH values. The effects of dye and salt concentrations on the membrane performance for dye purification were investigated. The dye and salt rejection rates would gradually decrease with an increase in the dye and salt concentrations. Then the influence of the volume concentration factor on dye purification during constant volume batch diafiltration process was studied. The results indicated that the higher of the concentration factor was, the better the concentration effect would be, and the less time would be needed.
危险品化学品经营许可证（带存储）