Electro catalytic Oxidation of Reactive Orange 122 in Wastewater by Using Three-Dimensional Electrochemical Reactor (3DER)

Abstract

In the present study, electrocatalytic treatment of Orange 122 in wastewater was studied by using a three-dimensional electrochemical reactor (3DER). Firstly, TiO2/AC, V O-2(5)/TiO2 /AC and WO3/TiO2/AC (over activated carbon) catalysts were prepared by a sol-gel method in aqueous solution. The process optimisation was carried out by investigating the effects of time, voltage, suspension's pH, dye concentration, the amount of supporting electrolyte (NaCl) and the type of catalysts. Optimum values for these parameters were found as 120 min., 15 V, 6.5, 250 mgL(-1) and 800 mgL(-1) respectively. The results obtained show that after 30 minutes only 30% colour was removed in the absence of activated carbon and this value increased to 60% in the presence of activated carbon. However, the percentage removal increased to 98% in the presence of all three catalytic materials under the same experimental conditions. In addition, for all three catalysts, the pseudo-first-order rate constants were obtained and the values were found to be between 1.12 x 10(-2) min(-1 )and 3.97 x 10(-2 )min(-1). The high removal efficiency of this system is attributed to the synergistic combination of adsorption, electrocatalytic and electrochemical oxidations occurring simultaneously during the oxidation process.