Fabrication and properties of Ti/Zr composite nanofiltration membrane

A stable Ti/Zr composite polymeric sol with Ti:Zr molar ratio of 1:1 was synthesized through the polymeric sol route. Disk α-Al₂O₃ supported mesoporous γ-Al₂O₃ membrane with an average pore size of 5-6 nm was used as support for nanofiltration membranes deposition. A defect-free Ti/Zr composite nanofiltration membrane superimposed on the support was fabricated via the dip-coating method followed by drying and calcination. The influence of calcination temperature on Ti/Zr powders was studied. The properties of Ti/Zr composite nanofiltration membrane were also investigated. Ti/Zr powders maintained amorphous state and microporous structure up to a calcination temperature of 500℃. The MWCO, mean pore size and pure water flux of Ti/Zr composite nanofiltration membrane calcined at 400℃ were 880, 1.49 nm and 4.3 L·m^-2·h^-1·MPa^-1, respectively. Under the condition of pH=6 and transmembrane pressure 0.8 MPa, the retention properties of Ti/Zr composite membrane towards 0.005 mol·L^-1 MgCl₂ and CaCl₂ solutions were 85% and 78%, respectively.