Abstract

TARANGO-BRITO, Eva Carina; RAMOS-GARCIA, Anabel; AVILA-CORDOBA, Liliana Ivette  and  BARRERA-DIAZ, Carlos Eduardo. Use of Electrooxidation as a Polishing Step for the Residual Water Obtained in a Solar Wastewater Treatment. J. Mex. Chem. Soc [online]. 2023, vol.67, n.4, pp.460-471.  Epub Apr 26, 2024. ISSN 1870-249X.  https://doi.org/10.29356/jmcs.v67i4.1976.

Dyes are widely used in many industrial operations for a variety of products; however, when wastewater is discharged without a treatment in rivers and lakes, severe environmental impacts are observed. In this work, the results of a solar wastewater treatment are presented. The solar treatment consists in parabolic heater coupled with a solar distiller which contains a ZnO plate that works as photocatalyst. Distilled water presents good characteristics; nevertheless, a residue that contains dye and intermediate products is also obtained. An electrooxidation treatment using boron-doped diamond electrodes (BDD), is applied at the residue as a polishing step. It was observed that wastewater quality improves when using an aqueous solution of pH 2.7 and a current density of 22.2 mA cm-2. Physicochemical test such as COD, and UV-Vis were used to evaluate the wastewater quality. It was found that 40 minutes are required to attain the improvement. This technology is environmental friendly since low energy is required (5 kW h L-1).

Keywords : Carmine red; degradation of dyes; solar distillation; electrooxidation.