Optimization of electro-Fenton process variables in terms of dye removal and energy consumption with response surface methodology

Abstract

Abstract Waste water containing reactive textile dyes constitutes an important environmental problem as they are permanent and dangerous. The Electro-Fenton (EF) method is promising as an effective technique for the degradation of organic materials such as dyestuffs. In this study, the optimization of effective variables in the removal of reactive yellow 145 azo textile dye by the EF using response surface methodology (RSM) was investigated. Central composite design (CCD) was used to study the combined effects of key parameters such as voltage (2.5–12.5 V), H2O2 addition (0.1–1.3 mL), pH (1.75–4.75), electrode spacing (0.25–3.25 cm), and treatment time (25–85 min). The optimum values of the variables to ensure the highest dye removal efficiency (approx. 93%) with the lowest energy consumption (approx. 3.4 Wh/L) are approximately 9.4 V voltage, pH 3.7, 2.5 cm electrode range, 1 mL H2O2 addition, and a 40-minute treatment time. ANOVA analysis of the predicted quadratic polynomial model showed a regression coefficient value of approximately 0.97 for both objective functions; this highlights the applicability of the model for navigating the design space. Simultaneous optimization of process parameters using RSM was achieved with a low number of experiments.