Response surface optimization of electrocoagulation for the removal of C.I. Disperse Red 343 and Isolan Bordeaux 2S-B dyes

Abstract

This study investigated the color removal of C.I. Disperse Red 343 and Isolan Bordeaux 2S-B dyes through the electrocoagulation (EC) process using an aluminum (Al) electrode. It explored the effects of pH, current, and electrolysis time, essential factors influencing color removal in the EC process. The Box-Behnken Design (BBD) of the Response Surface Method (RSM) was utilized to comprehend the statistical behavior of the system. Both dyes exhibited color removal responses that were well-suited to the quadratic model. The coefficients of determination (R2) for color removal in the EC process were notably high, 0.9896 for C.I. Disperse Red 343 and 0.999 for Isolan Bordeaux 2S-B. Correspondingly, the R2-adj values were 0.9708 and 0.9972, respectively. These R2 and R2-adj values approaching unity affirm the consistency between experimental outcomes and statistical inferences, indicating the effectiveness of the BBD in discerning process parameter effects. The optimized pH levels for color removal were determined as 6.76 for C.I. Disperse Red 343 and 5.66 for Isolan Bordeaux 2S-B. Ideal current values were found to be 0.06 A for C.I. Disperse Red 343 and 0.08 A for Isolan Bordeaux 2S-B, with corresponding times of 12.73 min and 14.95 min, respectively. Moreover, the calculated operating costs at optimum conditions were $0.055/m3 for C.I. Disperse Red 343 and $0.088/m3 for Isolan Bordeaux 2S-B. A comparison under identical conditions revealed a higher efficiency in color removal for the C.I. Disperse Red 343 when compared with Isolan Bordeaux 2S-B.