Resumen

CASTANEDA JUAREZ, Monserrat et al. ELECTROSYNTHESIS OF SODIUM AND POTASSIUM FERRATE FOR THE TREATMENT OF INDIGO BLUE AQUEOUS SOLUTIONS AND DENIM WASTEWATER. Rev. Int. Contam. Ambient [online]. 2020, vol.36, n.3, pp.607-622.  Epub 04-Mayo-2021. ISSN 0188-4999.  https://doi.org/10.20937/rica.53381.

Synthetic dyes are widely used in the textile industry. It is estimated that about 2-50 % of these dyes are lost during the dying process and released in the effluents. These compounds are highly colored and can cause severe contamination of water sources. In this study, ferrate has been employed for the treatment of indigo blue aqueous solutions and denim wastewater. The electrosynthesis of ferrate was carried out using a 24 factorial design and the optimal conditions were found: current density of 100 mA/cm2, room temperature, kind and concentration of electrolyte, NaOH 20 M. Under these conditions, 6.89 g/L (41.54 mM) of ferrate was produced. The successful synthesis of ferrate was confirmed using infrared spectroscopy, ultraviolet spectroscopy, and cyclic voltammetry. The electrosynthesized sodium ferrate (Na2FeO4) and potassium ferrate (K2FeO4) were evaluated in a jar test. The maximum dye removal percentage (> 77 %) was achieved using Na2FeO4 at a dose of 300 mg/L. In denim wastewater, the best color removal efficiency was 92.51 % using 200 mg/L of K2FeO4 at 30 min. The increased biodegradability index (0.98) after treatment by K2FeO4 confirmed that the biorefractory compounds were oxidized/removed.

Palabras llave : wastewater treatment; coagulation-flocculation; oxidation; textile effluent; biodegradability index.