A Comparison of Five Different Photocatalysts in the Degradation of Methylene Blue Dye

摘要

The photocatalyst such as titanium dioxide(TiO_2), is known for its effectiveness in treating waste from industrial pollutions such as dyes, pesticides and other emerging contaminants. In decades, TiO_2 has attracted attention from worldwide researchers because it is cheap, abundant and stable. In this research, we are trying to find alternative materials that can endeavor better results or at least, identical to TiO_2 in the degradation of methylene blue (MB) dye. The photocatalysts that are in focus would be bismuth compounds which are sodium bismuthate(BiNaO_3), bismuth vanadate(BiVO_4), bismuth titanate(Bi_2O_3 · 2TiO_2), and bismuth oxide(Bi_2O_3). Degussa P25 TiO_2 is used as a control experiment. For the duration of complete degradation of MB, BiNaO_3 took about 2 hours, BiVO_4 2 hours and 40 minutes, Bi_2O_3 · 2TiO_2 4 hours and 40 minutes, Bi_2O_3 5 hours, and finally P25 TiO_2 took about 6 hours and 20 minutes. The degradation rate at 120 minutes is as follows : BiNaO_3 (100%) > BiVO_4 (88%) > Bi_2O_3 · 2TiO_2 (58%)> Bi_2O_3 (56%) > P25 TiO_2 (47%). In conclusion, all of these bismuth compunds are possible to be used in degradation of methylene blue dye and results shows that the degradation rate are relatively faster than TiO_2 for all the bismuth compounds that were used.