Preparation and characterization of tubular supported ceramic microfiltration membranes from fly ash

Crack-free tubular supported ceramic microfiltration membranes have been prepared by a slip-casting method using refined fly ash as the raw material. The effects of slip concentration, casting time, and withdrawal speed on the pore size distribution, weight gain, and morphology structure of the sintered membranes have been investigated. Scanning electron microscopy images showed that optimization of the slip concentration could avoid crack formation in the coating. The weight gain of the sintered membrane increased linearly with the square root of the casting time. However, the effects of casting time and withdrawal rate on the pore size distribution of the sintered membrane proved to be insignificant. Furthermore, the pore size distribution of the sintered membrane became sharp upon applying a second coating. The average pore diameter and pure water permeability of the double-coated membrane were 0.77 mu m and 1.56 x 10(4) L m(-2) h(-1) bar(-1), respectively, with a transmembrane pressure of 0.1 MPa at room temperature. (C) 2011 Elsevier B.V. All rights reserved.