Blue dye degradation in an aqueous medium by a combined photocatalytic and bacterial biodegradation process

Authors: GABRIELA PEREZ OSORIO, FLOR DEL ROCIO HERNANDEZ GOMEZ, JANETTE ARRIOLA MORALES, MARIBEL CASTILLO MORALES, JOSE CARLOS MENDOZA HERNANDEZ

Abstract: This paper aimed at implementing a treatment system for polluted water with textile dyes, starting with a photocatalytic decomposition process using sunlight as a source of energy and continuing with a bacterial biodegradation process, in order to reach degradation percentages higher than those obtained using only one of the processes mentioned above. When water treatment with the dye in the combined system was over, an acute ecotoxicity test was performed to make sure that toxic metabolites were not produced due to biodegradation. Solophenyl Blue azoic dye, and Erionyl Blue and Terasil Blue anthraquinone dye-colored solutions were treated with the Pd/Al$_{80}$ Ce$_{10}$ Zr$_{10}$ catalyst in a solar collector for the photocatalytic process. On the other hand, the waste dye, which was obtained from photocatalysis with a bacterial consortium from polluted areas by metals and hydrocarbons in aerobic conditions, was inoculated for biodegradation. Biodegradation was obtained for the dyes after both processes as 90.91% for the Solophenyl Blue azoic dye, and 87.80% and 87.94%, respectively, for the Erionyl Blue and Terasil Blue anthraquinone dyes. After the degradation processes, it was proven, via an ecotoxicity test with Daphnia magna, that toxic metabolites had not been produced.

Keywords: Water pollution, dyes, photocatalysis, solar radiation, bacterial degradation, toxicity

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