Box–Behnken factorial design study of the variables affecting metal electrodeposition in membraneless fluidized bed electrodes

Abstract

AbstractBACKGROUND: Heavy metal removal from industrial wastewaters has been studied intensively since it is well known that they can cause severe problems to human health and aquatic life, even at very low concentrations. Traditional precipitation or adsorption technologies only transfer the problem to the solid phase, therefore new technologies, such as electrodeposition using fluidized bed electrodes (FBE), have been considered to avoid contamination.RESULTS: Copper electrodeposition from diluted solutions was carried out using a membraneless FBE. The supporting electrolyte concentration (Cs) was the main variable affecting the current efficiency (CE), energy consumption (EC), and space‐time yield (Y). Although it does not change the response surface morphology, increasing Cs there was an important improvement of CE, Y, and EC. The effects of current and bed expansion are much more complex, since an interaction effect between these two variables was verified. Considering only the region of active kinetic control, copper can be optimally recovered with CE > 90%, Y ∼93 kg h−1 m−3, and EC ∼3.2 kWh kg−1 by applying the highest levels of the independent variables.CONCLUSIONS: The results suggest that electrodeposition using a membraneless FBE is an excellent method for the treatment of effluents contaminated with copper or other metals. © 2012 Society of Chemical Industry