Low temperature sintering preparation of high-permeability TiO2/Ti composite membrane via facile coating method

Abstract

Core–shell structured grains were synthesized for low temperature sintering preparation of TiO2/Ti composite microfiltration (MF) membrane via facile coating method. An optimized facile spraying coating method was proposed to prepare the microfiltration membrane directly onto macroporous support (13μm), with the aid of sol nanoparticles coating. The spraying coating combined with the substrate heating process was proposed to make the sol into gel in short period of time, so that TiO2 particles could be cross-linked and formed continuous membrane without infiltration. This proposed method could directly prepare the microfiltration membrane onto macroporous substrate, eliminating the step of the intermediate layer fabrication, so that the high-permeability TiO2/Ti composite membrane could be prepared. Moreover, a core–shell structured grain was synthesized to prepare TiO2/Ti composite membrane at lower temperature of 950°C. The proposed method resolved the problem of thermal expansion mismatch of ceramic membranes and metallic supports for the higher temperature sintering process, so that the defect-free TiO2/Ti composite membranes could be obtained. The prepared TiO2/Ti composite MF membranes showed the most frequent pore size of 380nm, and a high pure water permeability of 1150Lm−2h−1bar−1. The proposed method has a considerable potential in fabricating such integrated ceramic-metallic composite membranes via the facile and low cost route.