Preparation of ceramic membrane and application to the crossflow microfiltration of soluble waste oil

Abstract Tubular-type alumina support for Al2O3 microfiltration membrane was prepared by extrusion method. The optimum solid content and dipping time of the Al2O3 slurry for microfiltration coating were 20 wt.% and 20 s, respectively. The pore size of the Al2O3 membrane was 200–300 nm, and the thickness was about 35 μm. This membrane was tested with a soluble waste oil which consisted of oil droplets whose mean diameter was 11 μm. The effects of the velocity and backflushing time on permeate flux were investigated. When backflushing was applied, whatever the conditions, the flux was increased. The steady-state flux when using backflushing was 1.5 times higher than that without backflushing. The maximum flux was obtained in operating conditions of 5 min filtration time, 4 s backflushing time and 2 m/s crossflow velocity. Also, the effect of cleaning agent on the cleaning of the fouled membrane was studied. The effective cleaning agent was toluene, and the maximum recovery of the initial flux was 84%.