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<p>In this study, the photocatalytic degradation of two biologically treated textile finishing wastewater was investigated using powdered TiO<sub>2</sub> and ZnO catalysts with UV-A lamp irradiation. Photodegradation and photodecolorization of the samples real textile industrial wastewater is observed directly proportional to pH and catalyst concentrations. Optimum catalyst concentration was found as 2 g l<sup>-1</sup> in both catalysts. COD removal in TiO<sub>2 </sub>assisted system was obtained two fold higher than ZnO assisted system depending characteristics of the wastewater samples. Optimum pH values were determined to be 5 and 9 for TiO<sub>2</sub> and ZnO assisted systems respectively. A COD removal of 45% and 23% were obtained using and ZnO catalysts respectively during 3 h irradiation. The effluents of photocatalytic treated samples using both catalysts displayed no acute toxicity at the end of 3 h irradiation time at optimum experimental conditions. Results, in conclusion, revealed that both TiO<sub>2</sub> and ZnO catalysts were found to be very effective in color removal and provided safe and proper effluents to meet discharge limits, even reuse guideline values. </p>
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