Document Type: Original Research Paper
Faculty of Advanced Technologies, Nano Chemical Engineering Department, Shiraz University, Shiraz, Iran
Ceramic membranes are considered as alternatives for their polymeric counterparts due to high mechanical strength and thermal resistance; thus long lifetime. Usually, asymmetric ceramic membranes are synthesized including several layers with different pore size distributions with the top-layer playing the main separation role. Titania has several properties such as photocatalytic activity and chemical stability making it sutitable as an option for the top-layer. This study is devoted to the preparation and characterization of a ceramic membrane, dip-coating of mesoporous interlayers and preparation of a microporous anatase top-layer via sol–gel technique. Moreover, the performance of the membrane modified by nano-copperis investigated for salt rejection enhancement. Membranes were characterized by FE-SEM and X-ray diffraction. The sol particle size was determined using DLS. Cross-flow filtration setup was used for membrane permeability and salt retention experiments. Membrane top-layer showed crystal structures including rutile and anatase phases. By increasing salt concentration, chloride rejection is decreased and retention is increased by increasing the pressure. In case of modified membranes using nano-copper, higher retentions are observed, with 35% rejection for NaCl and 73% for Na2SO4.