SO42−, Cl−, Br−, and TDS removal by semi continuous electrocoagulation reactor using rotating anode

Abstract

In this study, the simultaneous removal of SO 4 2 − , Cl − , Br − , and TDS from saline lake water was investigated using an emerging electrocoagulation (EC) reactor in a batch and a semi-continuous electrocoagulation mode (batch recirculation system). The possibility of the EC process in salt removal and sludge production were evaluated. The EC continuous reactor with rotating anode was used and the effect of the impeller plate anode was validated. Several variables were estimated to set the optimum operating conditions for a batch system. The effects of variables such as rotation speed (rpm), retention time (min), recirculation flow rate, current density (mA/cm 2 ), inter space distance (mm), pH solution, and continuous flow system were optimized. These operational parameters were set at 75 rpm, 10 min, 4 L/min, 2 mA/cm 2 , pH 8, 1 cm 2 , and 0.25 L/min, respectively. Statistical analyses were performed to determine the optimal EC conditions. The results revealed that the maximum removal efficiency of SO 4 2 − , Cl − , Br − , and TDS were 90.2%, 93.4%, 90.8%, and 92.3%, respectively. Electrical energy, aluminum consumption, chemical reagents, and sludge production were calculated to achieve an operating cost per m 3 of $0.1766. The sludge and treated water were characterized, and the mechanism of the EC technology was assessed. The results revealed that treated water with the use of the EC process was very efficient, with a low overall consumption cost. • SO 4 2 − , Cl − , Br − , and TDS are limited via physical adsorption with Al hydroxides. • Impeller plates of rotating anodes were used. • EC rotation speed, retention time, pH, and current density were the key parameters. • The EC technology revealed efficiency in saline water treatment.