Factors Affecting Removal Efficiency of Mercurochrome from Aqueous Solution Via Electrocoagulation Using Zinc Electrodes

The aim of using electrocoagulation process to remove Mercurochrome dye from wastewater was studied. Zinc electrodes were used in an electrolysis cell with a capacity of 300 ml and the effect of the following factors was studied: initial dye concentration (10-25 ppm), voltage (10-30 V), distance (1 cm), coagulation time (1-100 min), surface area (24.5-28 cm2), effect of adding NaCl in Na2SO4 at concentrations of (10-30 ppm) and temperature (303-333 K). The results of the experiments showed that the removal efficiency increases with increasing temperature, initial concentration, applied voltage, electrode surface area, coagulation time, and addition of NaCI. The efficiency decreases with increasing electrode spacing and addition of Na2SO4. The maximum removal (96%) was achieved at 25 ppm, 333 K, and 30 V and with an area of ​​28 cm2 and a spacing of 1cm with a time of 100 min. The thermodynamic functions (delta S, delta H, delta G) were calculated. The values ​​of these functions indicate that the process is spontaneous, endothermic, and random. The kinetics of the reaction at the best removal ratio were studied and found to follow first-order kinetics. The thermodynamic functions of the activated complex were studied by the negative activation entropy value , indicating that the activated complex is more ordered than the reactants.