アナターゼ・ルチル混合型酸化チタンの光触媒作用による窒素酸化物の浄化

Abstract

The purpose of this study is to manufacture a functionally graded material (FGM) to treat nitrogen oxides (NOx). The problem of air pollution is attracting attention all over the world. NOx treatment is one of the most important aspects. Photocatalytic materials can be used to combat air pollution. These materials make use of the processes of oxidation and catalysis on their surface. Titanium dioxide (TiO2) is used as the photocatalytic material. China clay is used to fix the powdered TiO2. The authors have devised a manufacturing technique to produce FGMs combining these two different constituents in a graded distribution. For the present experiment, thick blocks of FGM were produced by a progressive lamination method using a solid-fluid separation technique. The material's characteristics in the removal of NOx were measured for two types of crystalline TiO2. The material was irradiated with ultraviolet light (10W, wavelength : 254nm, 356nm) in an atmosphere of NOx. NOx was oxidized and trapped on the surface of the material. To measure the trapped NOx, the material was immersed in distilled water in order to release the nitric acid ions. The density of the nitric acid ions released was measured in a flow injection analysis. The manufacturing sintering temperature that ensured the optimal removal of NOx was 800℃. It can be conclude that there is a fair chance for achieving an improvement in the air pollution problem using materials of this kind.