Yellow 2G dye degradation by electro-Fenton process using steel electrode as catalysis and its phytotoxicity effect.

Abstract

The heterogeneous electro-Fenton process degradation of Yellow 2G from wastewater was studied using a batch reactor. The COD of the wastewater used in treatment experiments was 163 mg O2·L-1 and the BOD5 was 17 mg O2·L-1 (hardly biodegradable). The treatment of the wastewater at different current densities (2.5 mA·cm- 2-12.5 mA·cm- 2), solution pH (3 and 6.6), reaction times (5-25 min), electrolyte nature (NaCl, Na2SO4) and electrolyte concentrations (0.15 g·L- 1-1 g·L- 1) was investigated. According to the results, the heterogeneous electro-Fenton process was suitable for the decolorization of wastewater containing Yellow 2G. The optimum conditions were current density of 12.5 mA·cm-2, initial pH of the wastewater neutral, 25 min of electrolysis treatment using an additive steel electrode as a source of catalysis and in the presence of 1 g NaCl·L-1. We obtained easily biodegradable water with a mineralization rate equal to 85% and non-toxicity confirmed by the pea grain germination test.