Preparation Of Graphene Oxide Nano-composite Membrane And Study On Its Anti-biofouling Property

Membrane separation process is wildly used in water purification due to simple device, no phase change, high efficiency, low energy consumption and no secondary pollution. Currently, membrane biofouling is one of the most challenging problems in membrane processes, resulting in a decrease of permeate water flux, membrane performance and membrane survival. Therefore, designing membranes that resist biofouling is crucial for sustainable use of membrane technology in water and wastewater treatment as well as desalination and wastewater reuse. In this study, we adopted graphene oxide (GO) and graphene oxide-silver nanocomposite (GO-AgNPs) in the preparation of two antifouling membrane through interfacial polymerization and vacuum filtration respectively. The mainly contents and results are as follows:(1) GO was introduced into interfacial polymerization process for preparing graphene oxide-polyamide thin film composite (GO-TFC) membrane. Microscopic showed that the surface of membrane became roughness after deposition of GO. The contact angle result indicated that the hydrophilicity of the membrane was enhanced by the modification of GO. Bovine serum albumin (BSA) and Escherichia coli (E. coli) were used to investigated the anti-adhesion properties of GO-TFC membrane. And the BSA adsorption dropped from 68.91 μg/cm2 to 48.22 μg/cm2 after the deposition of GO. The antibacterial results showed that more than 79.3%E. coli was killed when contacted with GO (80 μg/mL) for 2 h. Even though the GO-TFC membrane showed no obvious antibacterial properties but after deposition of GO, the properties of hydrophilic and antibiofouling were improved.(2) GO-AgNPs was prepared through simple ultrasound heating processing in the presence of sodium citrate as reducing agent. The antibacterial activity of the GO-AgNPs against E. coli was investigated using the dynamics of growth curve and fluorescence experiment. The results showed that AgNPs, represented by dark spots, were homogeneously assembled on the GO. The prepared composite exhibit stronger antibacterial activity against the E. coli, and the excellent antibacterial effect of GO-AgNPs due to a synergistic effect of GO and AgNPs. These promising results showed that it was an outstanding antibacterial material.(3) The GO-AgNPs membrane was pared through vaccum filtration process. The contact angle result indicated that the hydrophilicity of the membrane was enhanced by the modification of modified GO-AgNPs. The presence of GO-AgNPs on the membrane exhibited a strong antibacterial activity, leading to 85.5% inactivation of E. coli after contacting with the membrane for 2 h. Under the continuous filtration test, the relative flux drop over GO-AgNPs membrane was 46%, which was significantly lower than that over the CA membrane 88%at 24 h of filtration. This study may have great potential in developing high-performance antibiofouling membrane for membrane separation processes.