Preparation and photocatalytic properties of macroporous honeycomb alumina ceramics used for water purification

In this work, porous alumina ceramics with highly ordered capillaries were successfully fabricated by ionotropic gelation process of alginate/alumina suspensions. By varying the initial solid loading (10-30 wt%) of slurries, the porosity of alumina ceramics ranged from 60.4% to 79.5% with controlled pore size (180-315 mu m). Due to the well-crosslinked macroporous structure and large specific surface areas, the porous ceramics were utilized as the photocatalyst supports of TiO2 catalysts whose photocatalytic activity was characterized by degrading methyl blue under UV irradiation. TiO2 coatings prepared by sol gel method demonstrated excellent adhesion to the substrates. When the solid loading of supports reached 15 wt%, the TiO2 coatings showed the highest photocatalytic efficiency of 79.52%. Besides, TiO2 films possessed nearly the same photocatalytic activity as titania/water suspension. Thus, the honeycomb ceramic prepared by self-organization process holds promise for use as photocatalyst supports in water purification without recycling process of powders. (C) 2013 Elsevier Ltd. All rights reserved.