Study on the Difference of Photochemical Efficiency of Sunlight Photocatalyst in Degradations Dye Aqueous RhB Solution in Different Seasons

Department of Safety Health and Environmental Engineering, National Yunlin University of Science and Technology, Yunlin, Taiwan

^* Corresponding author: nike05270601@gmail.com

Abstract

The purpose of this study is to modify TiO₂ with bismuth oxide (Bi₂O3) and potassium hydrogen iodate (KH(IO₃)2) to research the effect of RhB degradation in natural sunlight within different seasons. The catalyst was made by fixing the mole% of I/Bi₂O₃/TiO₂ to 2: 1: 1, 10 mg/L of RhB was the target pollutant, and compare the difference of I/Bi₂O₃/TiO₂ modified catalysts in natural sunlight within different seasons. According to the XRD crystal phase identification, it can be seen that the characteristic peaks of the modified photocatalysts are consistent with the structures of anatase and rutile, had not be offset. At the same time, there aren’t other impurity crystal phases were found, and the photocatalysts is still retains the basic type, which means we successfully prepared the I/Bi₂O₃/TiO₂ composite photocatalysts. The result of UV-visible analysis showed that the composite photocatalysts had the phenomenon of red-shift, and there was a second absorption wavelength in the range of visible light. That is, the energy gap will be reduced and the utilization under visible light will be increased by the addition of iodine and bismuth oxide. The pure TiO₂ has no the phenomenon above. In this study, the photodegradation efficiency in 60 minutes of photocatalysts experiments under the actual solar light at summer and winter were 58.9% and 44.4% respectively. The photocatalysts still retained a good removal efficiency after five repeat photocatalytic. In other words, the photocatalyst has the characteristics of excellent durability.