electrofenton process based on iron electrodes for decoloration of malachite green from aqueous solutions

Abstract: the electrofenton process has been widely used in dye removal due to its reduced energy consumption, high oxidation strength and production of environmentally friendly by-products. malachite green (mg) as a cationic dark green dye (λmax = 617 nm) is available in the form of the chloride salt [c6h5c(c6h4n(ch3)2)2]cl. it was most widely used for coloring purposes in industries of fibers and as an antifungal and antiparasitic agent in aquaculture [1, 2]. the aim of the present work was to degrade the mg content in aqueous samples using electrofenton process. all experiments were performed in a glass cubic reactor with a total volume of 900 ml with two iron electrodes (63 × 80 × 63 mm) connected to a direct current power supply. the effect of five effective parameters such as applied voltage (5, 10, 15, 20 v), ionic strength (0, 0.05, 0.1, 0.2 m), dye concentration (50, 100, 200, 250 mg l-1), ph of solution (2, 3, 4, 6) and percentage of h2o2 (10, 20, 25, 30 %) were investigated in four levels and optimized by taguchi orthogonal array design method (oa16). the residual concentrations of mg after electrofenton process were spectrophotometrically determined in the time range of 0-90 min with time intervals of 10 min and the removal efficiencies were calculated. based on the results, the optimum conditions were obtained as ph: 2, voltage: 10 v, h2o2: 10%, salt concentration (na2so4): 0.2 m and the initial concentration of mg: 50 mg l-1. under the optimum conditions, more than 98 % of mgwas removed during 10 min. the results obtained in this work, demonstrate mg can be effectively decolorized by electrofenton process with maximum efficiency at a short time