Properties of TiO₂ FGM Tile Produced by Filtration and Expression for Air Purification

抄録

Properties of TiO₂ Functionally Graded Material (FGM) tile that combined TiO₂ and Korean kaolin (Al₂Si₂O₅(OH)₄) in a graded distribution were experimentally investigated. TiO₂ is an excellent photocatalysis material, however, it does not have enough the mechanical strength. Therefore, FGMs were used as the photocatalysis materials with mechanical strength. To improve the mechanical properties, kaolin was selected as a binder. The production process of FGMs has been proposed. TiO₂ FGMs were produced by progressive lamination, solid-liquid separation and mechanical expression involving filtration, mechanical compression and sintering. By this process, it is easy to control the thickness of FGMs. The results show that porosity in FGM depends on the content of TiO₂. The material was found to have a bending strength of 2.5 MPa. The bending strength increases with increasing compression pressure. The results also show that these properties of FGM, such as porosity, mechanical strength, etc., can be controlled by content of TiO₂ and compression pressure. Based on an optimal design of production conditions, TiO₂ FGMs were developed for the nitrogen oxides (NO_x) removal. NO_x removal efficiency increases with increasing the content of TiO₂. NO_x removal efficiency was found to drop drastically at 900°C, since TiO₂ changes from anatase type to rutile type at 900°C or more. It can be concluded that TiO₂ FGMs developed using solid-liquid separation technique have an application to the air purification because FGMs have high NO_x reduction efficiency as well as good mechanical properties.