Industrial dyes are considered as emergent contaminants due to its presence in wastewaters and its resistance for being treated by conventional systems. In this study, a real industrial wastewater, with Basonyl Blue 636 (a commercial dye used in lithographic industry), was treated by TiO2-based solar photocatalysis. The tests were conducted in a pilot-scale solar CPC reactor with commercial P25 as catalyst. For assessing the effects of the operating variables in the photocatalytic degradation, a full-composite experimental design was used. The catalyst concentration and dye dilution were selected as the controllable factors and the response surface methodology (RSM) was used for optimizing the photodegradation process. For each experimental test, 36 000 J m<sup>-2</sup> of solar UV radiation was accumulated. Direct photolysis and its adsorption were also analyzed to establish the net effect of photocatalysis. The results showed that the highest percentage of degradation achieved was 22.35% with a dilution of 0.16 and a catalyst concentration of 0.35 g/L. The process was optimized with the RSM and the results obtained were: a degradation of 21.94% with a dye dilution of 0.17 and a catalyst concentration of 0.36 g/L (see Fig. 1). The effects of photolysis and dye adsorption<sub> </sub>are negligible (represented 2.6% and 5.45 % of the dye degradation, respectively) respect to the overall degradation. The experimental data obtained with the optimal parameters follows a modified L-H kinetic form, which included the LVREA. The kinetic and binding constants were calculated with the Generalized reduced gradientmethod.

Statistical optimization of the solar photocatalytic degradation of a commercial dye contained in a real industrial wastewater with a pilot-scale CPC reactor

251st National Meeting (2016)

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