In Situ Solvothermal Crystallization of TiO2 Nanostructure on Alumina Granules for Photocatalytic Wastewater Treatment

Synthesis of nanostructure titania powders and in situ crystallization of anatase coating layer on sintered alumina granules by solvothermal method were investigated. In coating process, addition of polyvinyl alcohol (PVA) as binder to solvothermal solution was also studied. Microstructure analyses of powders showed that crystallization and growth of nanostructure anatase phase in a thin gel layer were enhanced with temperature increase. The titania nanopowders synthesized at 120 °C and 8 h represented photodegradation of methyl orange solution as model wastewater up to maximum 94% yield in slurry photoreactor. However, in coating process, with increasing temperature to 220 °C and coating time to 24 h, adhesion and photocatalytic properties of the coated layer were improved. Furthermore, PVA binder addition led to formation of more uniform layer with less attrition loss in the reactor.