Combined Electrochemical Processes for Real Chemical Industrial Liquid Waste Treatment: Optimization and Kinetic Studies

In this study, the efficacy of electrocoagulation (EC), electro-Fenton (EF), and a combined EC/EF approach—in treating real chemical industrial wastewater—was investigated. Optimal conditions for the EC process were identified at an applied current density of 480 mA/cm2 and a duration of 13 min. In contrast, the EF process demonstrated peak performance at a current density of 350 mA/cm2 and a duration of 147 min. Importantly, a consistent supporting electrolyte concentration of NaCl at 3.3 g/L was maintained for both EC and EF treatments. Under these optimized conditions, the EC process showcased superior efficiency in total suspended solids (TSS) removal, achieving an impressive 82.87% removal rate, whereas the EF process yielded a moderate 41.41%. Conversely, the EF process outperformed in organic removal, registering an exceptional 96.83% removal rate compared to the 53.21% achieved by the EC treatment. Remarkably, the sequential application of both EC and EF processes led to the complete removal of TSS and organics, resulting in a CI reduction to zero. Biological testing corroborated the effectiveness of the combined treatment, confirming the water to be 100% sterilized and thereby suitable for both irrigation and potable use. The novelty of this study lies in the sequential application of electrocoagulation (EC) and electro-Fenton (EF) processes, which, for the first time, achieved complete removal of total suspended solids (TSS) and organics from real chemical industrial wastewater, while also sterilizing the water, rendering it suitable for irrigation and potable use.