Effect of clay addition to Al2O3-agar mixture on pore size and distribution of tubular Al2O3 membrane support fabricated byagar gelcasting

Abstract

The addition of clay particles— kaolin or bentonite—into the mixture of Al2O3 slurry and agar solution was examined for creating pores with controllable size in tubular Al2O3 membrane. The mixtures were prepared and then molded out of glass tubes using the method of agar gelcasting. The green, gelcast Al2O3 tubes were sintered at 1350 °C for 1 h for membrane application. The effect of clay addition from 0 to 2 wt% into the mixture on pore size and structure of Al2O3 tubes was observed with SEM. The addition of bentonite provided less uniform pore size and distribution than that of kaolin. Additionally, the step of ball milling the clay particles to make complete dispersion prior to adding to the mixtures was needed to create more uniform pore size and distribution. The ball milling time of 60 min was the optimum condition for preparing Al2O3 membrane support.