Jutaporn Chanathaworn, Charun Bunyakan, Wisitsree Wiyaratn, and Juntima Chungsiriporn

pp. 203 - 210

Abstract

Photocatalytic decolorization of rhodamine B (RB) and malachite green (MG) basic dyes in aqueous solution was
evaluated using TiO₂ powder as a semiconductor photocatalyst under UV black light irradiation. A 0.5 L batch photoreactor
containing dyeing solution was installed in a stainless steel chamber with air cooling under irradiation. The TiO₂
 powder was
characterized by XRD observation and it was shown that the nanoparticles could be identified as 73 nm anatase crystals. The
effects of operational parameters such as light intensity (0-114 W/m²
), initial dye concentration (10-30 mg/L), and TiO₂ powder
loading (0.5-1.5 g/L) on the decolorization of dye samples were examined. The photocatalytic decolorization rate depended on
the pollutant’s structure, such that the MG dye could be removed faster than the RB dye. Decolorization efficiency (%) of the
photocatalytic system increased with increasing TiO₂
 loading and light intensity; however, it decreased with increasing initial
dye concentration. A loading of 1.5 g TiO₂
/L, initial dye concentration of 20 mg/L, and light intensity of 114 W/m²
 were found
to yield the highest removal efficiency of dye solution based on time requirement. The kinetics are of first order and depend
on the TiO₂
 powder loading and dye structure. The research had a perfect application foreground.