Comparative study of the use of iron and aluminum electrodes for the removal of neutral red by electrocoagulation

This study is presents a comparative evaluation of the efficacy of two electrochemical systems (Fe and Al electrodes) for the removal of neutral red by electrocoagulation. The investigation was conducted by studying the influence of key operating parameters, followed by statistical optimization using Response Surface Methodology (RSM) coupled with a Centered Composite Design (CCD). The parameters studied included the initial dye concentration (25–100 mg/L), the pH of the solution (5–9), and the electrolysis time (20–60 min), with removal efficiency monitored by UV-visible spectrophotometry at 528 nm. ANOVA analysis confirmed the significance of second-degree polynomial models with coefficients of determination R² of 90.88% for the iron system and 91.18% for aluminum, and adjusted R² values of 80.62% and 81.86%, respectively. The response surfaces revealed complex interactions between the variables, including a strong synergy between pH and electrolysis time. Optimization led to an efficiency of 98.05% for iron electrodes obtained at a concentration of 61.78 mg/L, pH of 8.42 and electrolysis time of 25.68 min while similar data for aluminum resulted to an efficiency of 95.39% obtained at a concentration of 61.72 mg/L, pH 7.50, and electrolysis time of 34.50 min. The iron system showed superior kinetics with a reduced time of about 10 min with slightly higher efficiency which is economically advantageous in terms of energy consumption. The results obtained thus highlight the virtues of electrocoagulation for treating textile effluents, with a particular attention for the iron system, which displays synergy in efficiency.