احمد آذری

In this study, a high-permeability ceramic nanofiltration membrane as well as a good rejection percentage was fabricated via a multilayer asymmetric structure. For this purpose, two types of porous cylindrical substrate mullite and mullite-alumina (50%) were fabricated by extrusion method. In the next step, by sol-gel method, titania and titania-zirconia colloidal sol were synthesised and cast in inner surface of substrates by using dip-coating method. Various tests such as Scanning Electron Microscopy (SEM), Specific Surface Area (BET) and X-ray diffraction pattern (XRD) were used to characterize the quality and microstructure of the fabricated membranes. After studying the microstructure of the membranes, the efficiency of the membranes including: permeability of distilled water, percentage of different single component salts rejectionn including: NaCl, CaCl2 and MgCL2 were investigated. Finally, the percentage of petroleum feed rejection was investigated by the final membranes. The performance results of the final titania-zirconia membranes showed that the percentage of rejection in the NF membranes is largely influenced by the mechanism of the Donan Repulsive. Also the results of percentage of petroleum feed rejecion for the final membranes showed that with increasing pressure, the percentage of COD rejecion increased. So at 7 bar, the percentage of COD rejecion for the final mulliteTZ and mullite-aluminaTZ membranes were obtained 98.65 and 98%, Respectively.