Fabrication and characterization of TiO2/ZrO2 ceramic membranes for nanofiltration

TiO2/ZrO2 ceramic nanofiltration membranes are successfully fabricated through the polymeric sol gel route followed by the dip-coating technique. Disk type alpha-alumina supported mesoporous gamma-alumina (pore size: 5-6 nm) is employed as the support in dip-coating. The unsupported and supported composite ceramic membranes are systematically characterized and evaluated in terms of phase composition, chemical stability, gas adsorption, molecular weight cut-off (MWCO), membrane pore size, water flux and salt rejection. It is found that the TiO2/ZrO2 ceramic membranes have amorphous phase at 400 and 500 degrees C, suggesting the high thermal stability. The fabricated membranes have the MWCO of 620-860 Da, corresponding to the membrane pore size of 1.2-1.5 nm. Relatively low water permeability can be attributed to the low microporosity of the membrane. Donnan exclusion is the dominant transport mechanism of the NF membrane in the single-component system, and salt rejection is closely related to the hydration properties of the ions (e.g., the hydration radius). (C) 2017 Elsevier Inc. All rights reserved.