Control of Chlorinated Volatile Pollutants at Indoor Air Levels Using Polymer-based Photocatalyst Composite

다국어 초록 (Multilingual Abstract)

In this study, polyaniline (PANI)-based TiO2 (PANI-TiO2) composites calcined at different temperatures were prepared and their applications for control of trichloroethylene (TCE) and tetrachloroethylene (TTCE) at indoor air levels were investigated. For these target compounds, the photocatalytic control efficiencies of PANI-TiO2 composites did not exhibit any trend with varying calcination temperatures (CTs). Rather, the average control efficiencies of PANI-TiO2 composites over 3-h photocatalytic process increased from 61 to 72% and from 21 to 39% for TCE and TTCE, respectively, as the CT increased from 350 to 450 ℃. However, for both the target compounds, the average control efficiencies of PANI-TiO2 composites decreased gradually as the CT increased further to 550 and 650 ℃. These results were ascribed to contents of anatase crystal phase and specific surface area of different particle sizes in the PANI-TiO2 composites, which were demonstrated by the X-ray diffraction and scanning electron microscopy images, respectively. At the lowest input concentration (IC, 0.1 ppm), average control efficiencies of TCE and TTCE were 72 and 39%, respectively, whereas at the highest IC (1.0 ppm) they were 52 and 18%, respectively. As stream flow rate increased from 0.1 to 1.0 L min-1, the average control efficiencies of TCE and TTCE decreased from ca. 100 to 47% and ca. 100 to 18%, respectively. In addition, the average control efficiencies of TCE and TTCE decreased from ca. 100 to 23% and ca. 100 to 8%, respectively as the relative humidity increased from 20 to 95%. Overall, these findings indicated that as-prepared PANI-TiO2 composites could be used efficiently for control of chlorinated compounds at indoor air levels, if operational conditions were optimized.

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