Design of economic photocatalytic system with low energy consumption, and high quantum yield, for the degradation of acid red 37 textile dye

This work aims to study the photocatalytic degradation of the textile dye pollutant, Acid Red 37, under UV irradiation in the bench scale batch photoreactor, designing an optimum system of nanometal oxides Ti02, ZnO and their mixtures with different weight ratios. The photocatalysts were synthesized and fully characterized by XRD, EDS and TEM. The photocatalytic degradation process was investigated as a function of pH, concentration of the dye pollutant and different ratios of the photocatalytic mixtures. Furthermore, the effect of adding electron scavengers; H202, Na2S208 and NaI04 was studied. The best photodegradation was observed under UV irradiation upon adding a ratio of (3:1) (Ti02: ZnO) at pH = 6.5 when the textile dye concentration is 1.0 x 10-4 mol/L. The efficiency of the studied photocatalytic degradation systems can be arranged in the order: UV/ZnO < UVITi02< UV/Ti02/ZnO < UV/Ti02/ZnO/H202 < UV/Ti02/ZnO/ Na2 S2 08 < UV/Ti02/ZnO/NaI04. The system designated as UVITi02/Zn0/(1.1-5.5)x10-3M NaI04 showed the highest photocatalytic degradation efficiency, with highest apparent quantum yield (11.1-16.6)% and the lowest electrical energy per order (37.0-22.2) kWh, indicating the lowest energy consumption relative to the other examined catalytic systems. Finally, these outcomes can be useful for photocatalysis with low depletion of electrical energy, greater amount of degradation and economical procedure. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.