Removal of sulfate by electrocoagulation with discontinuous electrodes in a continuous system

This study aimed to remove sulfate from water solution through electrocoagulation, using multiple electrodes in a continuous flow system. Moreover, the effect of important parameters, including scenarios for voltages applying to electrodes, flow rate, primary sulfate concentration, and pH on the sulfate removal process was evaluated. The experimental reactor was a rectangular box of 20 × 10 × 6, all in cm. The electrodes were plates of grade 1050 aluminum. The highest sulfate removal was 87% that occurred at a voltage of 30 V and 10 mL/min of flow rate (retention time = 135 min) at pH = 5.5, when the initial concentration of sulfate was 500 mg/L. The highest sulfate removal rate in non-uniform voltage configuration was observed in the arrangement of 10, 20, and 30 V (upstream, middle, and downstream, respectively) during 135 min for 10 mL/min flow rate. On the other hand, the economic assessment revealed that the lowest amount of electrical energy consumed for removal of one mg/g of sulfate occurs at a 10 V uniform voltage among the electrodes. The results showed that the electrocoagulation technique could successfully be applied to continuous flow systems to remove sulfate from aquatic environments.