Evaluation of electrochemical peroxidation (ECP) process variables for removal of co-complex dye using a central composite design

Abstract

In this study, electrochemical peroxidation was employed to remove color and total organic carbon (TOC) from co-complex (acid yellow 194) dye using iron electrodes in a batch-mode operation. The effects and relationships of the process variables were evaluated, and optimizations were carried out using response surface methodology to maximize removal efficiencies and minimize operating costs in relation to energy, electrode, and chemical (such as H₂O₂) consumptions. The initial pH (2.0–6.0 pH_i), conductivity (500–2,500 μS/cm, k), initial dye concentration (100–800 mg/L, C₀), current density (10–30 A/m², j), operating time (4–20 min, t), and dosage of H₂O₂ (2–10 mM or 175–860 μL/L, ) were selected as independent variables. The proposed models fit very well with experimental data, evidenced by high R² correlation coefficients (>90%). Maximum color removals were 98 and 80% when C₀ was 275 and 625 mg/L, respectively. In contrast, maximum TOC removals were poor (52 and 40% when C₀ was 275 and 625 mg/L, respectively). On the other hand, color and TOC removals were found to be 86 and 33.5%, respectively, at optimum conditions (C₀, 275 mg/L; pH_i 3; , 1.010 μS/cm; , 5.1 mM; j, 15 A/m; and t, 8.02 min). The calculated operating cost at optimized conditions was 0.647 €/m.

Keywords:

• Electrochemical peroxidation process
• Response surface methodology
• Acid yellow 194
• Operating cost