Direct red 81 dye removal by a continuous flow electrocoagulation/flotation reactor

Direct red 81 (DR 81) dye removal by electrocoagulation /flotation process using aluminum electrode was studied in a continuous electrochemical reactor. The designed reactor includes an electrochemical cell and a sludge separation cell. The effect of operating parameters such as current density and inlet flow rate (Q) on the dye, COD, suspended concentration (SS) and turbidity removal and aluminum dissolution rate were studied and the electrical energy consumption was calculated. The EC formed sludge has been investigated and the influence of current density and inlet flow rate on it has been studied. It was found that the increasing of the current density up to 200 A/m2 had increased the dye removal efficiency and the optimum inlet flow rate for EC process was the minimum at 10 l/h and it has increased the electrical energy consumption. Current efficiency (Faradic yield) was strongly depending on flow rates and current densities. SEEC was proportionally independent of the inlet flow rate. On the contrary a decrease in the electrical energy consumption EEC is observed when the inlet flow rate increases. Despite the increasing of the inlet flow rate, the specific electrical energy consumption remained at 52-58 kW h/kg Al at 150 A/m2. The total formed sludge was corresponding with increasing applied current density.© 2013 Elsevier B.V. All rights reserved.