Removal of toxic metals from aqueous effluents by electrodeposition in a spouted bed electrochemical reactor

Abstract

This work investigates the removal of metal ions from synthetic aqueous effluents using a spouted bed electrochemical reactor whose cathode was composed of 1.0 mm copper particles. Using a Box–Behnken factorial design, the effects of current (I), electrode thickness (L), draught distance (d) and support electrolyte concentration (Cs) on current efficiency (CE), space–time yield (Y) and energy consumption (EC) were analysed. The results were statistically analysed and the effect of each variable was evaluated using the surface response methodology. The results showed that Cs is the most important variable to consider in the process optimization. A current of 8.0 A can be applied in order to obtain high Y and CE with an acceptable EC. Electrode thicknesses greater than 1.3 cm are not recommended because the irregular potential distribution leads to a Y drop owing to the low CE observed for this condition. The draught distance does not have statistical significance; therefore, the particle circulation rate is not important in this kind of electrochemical reactor.