Processing of kaolin-based microfiltration membranes

Abstract

Kaolin-based membranes with a pore size of 0.30-0.40 μm were successfully prepared by a simple pressing route using low-cost starting materials, kaolin and sodium borate. The prepared green bodies were sintered at different temperatures ranging between 900 and 1200°C. The sintered membranes were characterized by X-ray diffraction, mercury porosimetry, scanning electron microscopy, and capillary flowmetry. It was observed that the porosity decreased with an increase in both the sintering temperature and the sodium borate content, whereas the flexural strength increased with an increase in both the sintering temperature and the sodium borate content. The air flow rate decreased with an increase in the sodium borate content. The typical porosity, flexural strength, and specific flow rate of the kaolin-based membrane sintered with 5 wt% sodium borate at 1100°C were 37%, 19 MPa, and 1 × 10 -3 L/min/cm2, respectively, at ap of 30 psi.