BACKGROUND: 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

Heavy metal removal from industrial wastewaters has been intensively studied, since it is well known that they can cause severe problems to human health and aquatic life, even at very low concentrations. In this work, it was demonstrated that electrodeposition in fluidized bed electrode (FBE) can be efficiently employed to remove metal ions from solution, avoid contamination, and recover the metal. Copper electrodeposition from diluted solutions was efficiently performed using a membraneless FBE. The average current efficiency (ACE), average energy consumption (AEC), and space-time yield (AY) was optimized taking into account the operational and process variables. It was noted that for all response variables studied, the raise of supporting electrolyte concentration (C s ) contributed to improvements in the process. The operational conditions current (I) and bed expansion (E) determined the values of CE, Y, and EC under activated control, but the initial copper concentration (C 0 ) determined how long the electrodeposition process will work under activated or mass transfer control, thus affecting the average values of CE, Y, and EC. Considering C 0 of 500 mg L -1 , copper can be optimally recovered with ACE [60 %, AY[38 kg h -1 m -3 , and AEC\4.0 kWh kg -1 by applying the lowest I and the highest levels of E and C s . It was concluded that the electrochemical technology using a membraneless FBE reactor is economically competitive and be applied for the treatment of wastewaters contaminated with copper or other metals.