The objective of this research was to investigate experimentally the removal the dyestuff from dyeing textile industrial wastewater by photosensitization process, for reusing it in the same industry or for domestic purpose and/ or irrigation. In this study, the photocatalytic decolorization of two collected samples of real and one prepared simulated textile industrial wastewater using titanium dioxide and zinc oxide were examined under natural weathering conditions. The effect of various operational parameters such as catalyst mass, type of catalyst, type of reactor, type of dye, dye concentration, and temperature were investigated.
Photolysis and photocatalytic treatments were carried out over a suspension of titanium dioxide or zinc oxide under solar irradiation. The progress of treatment stages was followed spectrophotometrically at different wavelength. Under optimal conditions, the extent of decolorization was 100% after different periods of time ranging from 10 to 100 minutes. The decolorization percentages differ with the difference in type of dye used in textile industry. The results indicate clearly that titanium dioxide and zinc oxide could be used efficiently in photocatalytic treatments of textile industrial wastewater. However, the activity fell in the sequence:
ZnO > TiO2 (Anatase) > TiO2 (Rutile)
Decolorization of real and simulated textile industrial wastewater without light and without catalyst was performed to demonstrate that decolorization of the dye depends on the presence of light and catalyst, both.