Preparation and mechanism analysis of high performance ceramic membrane by spray coating

A spray coating method was proposed to fabricate an α-Al₂O₃ micro-filtration membrane with excellent performance. It was observed that air gaps could form inside the support during the coating stage that effectively prevent membrane forming particles from penetrating into the support without an intermediate layer. Thus the pure water permeability of the membrane with average pore size of 0.13 μm and thickness of 25.46 μm could reach 2893 Lm^-2 h^-1 bar^-1. The effects of firing conditions, membrane thickness and backwash or backpulse conditions on the pore size distribution of the membrane were investigated. Meanwhile the prepared membrane could sustain good filtration performance and mechanical integrity during backpulsing and backwashing processes under the transmembrane pressure (TMP) of 8 bar, which also exhibited a rejection rate of 98.8% for the carbon ink with an average particle size of 164 nm.