Taguchi’s Approach Uses Electrocoagulation Method with Different Electrode Connection Types for Removal of Malachite Green

This study investigated the removal of Malachite Green (MG) from water through electrocoagulation (EC) using Fe–Fe, Al–Al, and Al–Fe electrode setups. The Taguchi method, employing an L25 (5^5) orthogonal array, focused on optimizing five key factors: current density (0.2–1.0 mA/cm²), pH (3–10), initial dye concentration (10–100 mg/L), distance between electrodes (5–25 mm), and duration (5–60 min). Signal-to-noise (S/N) ratio and ANOVA evaluations indicated that pH (10) with Fe-Fe electrodes and current density (0.8 mA/cm²) with Al-Al electrodes were the most significant variables. Increasing the initial dye concentration or the distance between electrodes raised the voltage and consistently increased the removal percentage (%R). Enhancing electrolyte concentration initially improved color removal %R to a certain extent, after which no further enhancements were observed. In terms of efficient MG removal from water, the Fe-Fe, Al-Al, and Fe-Al configurations demonstrated efficiencies ranging from 12.59% to 98.6%. The initial concentration had a substantial impact on results (with ANOVA contributions of 44.3% to 34.9%), closely followed by the duration of electrolysis. Optimal conditions yielded 88% to 100% removal with less than 3% deviation from predicted values. The maximum conditions for color removal varied based on electrode material: pH (10, 8, and 10), current density (1.0, 0.8, and 0.8 mA/cm²), contact time (20, 60,and  60 min), distance between electrodes (20, 15,and 15 mm), and initial concentration (100 mg/L). The ideal salt concentration was determined to be 0.1 g/L, with an optimal stirring speed of 150 rpm. The Taguchi design effectively optimized EC performance, recommending Fe-Fe electrodes for superior efficiency compared to Al-Al and Fe-Al setups.