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

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.