Removal of Acid Red 131 by Peroxi-Coagulation Using Stainless Steel and Aluminum Electrodes: a Comparative Study

Azo dyes have great application in industries like textile. However, their presence poses a lot of concerns to the environment and human health such as carcinogenic effect. Electrochemical processes such as peroxi-coagulation (PC) are cost effective and efficient advanced oxidation processes which have been investigated extensively. This study aimed to conduct a comparative study on removal of Acid red 131 as an azo dye via PC process using stainless steel (SS) and aluminum (Al) electrodes as anode and graphite as cathode. Parameters including dye concentration, current density, initial pH, aeration rate, and electrode’s surface area were investigated. According to the results, the optimum condition for both electrodes was achieved at electrode’s surface area = 60 cm 2 , pH = 7, and aeration rate = 1.5 L/min. Also, the optimum current of 0.6 A and 0.9 A were selected for SS and Al, respectively. The removal percentages at these conditions were measured 98% and 93% after 120 min for SS and Al, respectively. Chemical oxygen demand (COD) removal was also investigated, and the removal percentage was recorded 93% and 79% for SS and Al after 180 min, respectively. The removal kinetics studies indicated that the pseudo-first order model best fitted for both electrodes. Based on the results, the SS electrode outperformed the Al electrode and facilitated the process.