Modeling electrowinning process in an expanded bed electrode

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

“…The greater the Δσ the sharper the potential and current profile inside the porous electrode, the more active zone being close to the counter‐electrode. Since the increase of acid concentration can reduce Δσ by increasing the solution conductivity, potential and current distribution inside the FBE will become more uniform, making the electrode more active in the zones close to the current feeder and avoiding very negative overpotentials responsible for the hydrogen evolution reaction (HER) close to the counter‐electrode;, consequently, the current efficiency increases. Furthermore, considering that the solid phase conductivity depends on the statistical probability of particle shocks, expansion also will have an influence on the solid phase conductivity, thus it would be expected that increasing the FBE expansion would cause the solid phase conductivity to drop.…”

“…, which indicates that the drawback of solid phase conductivity drop did not significantly impact the process. The rise in applied current, besides diminishing inactive zones and anodic dissolution in electrode interiors,, , should be performed along with improvements in mass transport coefficient to avoid surpassing the limit current since it could lead to lower CE values. Therefore, for a current of 4.0 A, the interaction effect between I and E observed on the response surface of Fig.…”

Heavy metal removal from simulated wastewater using electrochemical technology: optimization of copper electrodeposition in a membraneless fluidized bed electrode

“…The greater the Dr the sharper the potential and current profile inside the porous electrode, being the more active zone close to the counter electrode. Since the increase of acid concentration can reduce Dr by increasing the solution conductivity, potential and current distribution inside the FBE will become more uniform, making the electrode more active in the zones close to the current feeder and avoiding very negative overpotentials responsible for the HER close to the counter electrode, consequently, the current efficiency increases, as experimentally observed for zinc (Lanza and Bertazzoli 2000) and copper (Ruotolo and Gubulin 2011) electrodeposition in a fixed bed electrode, for copper electrodeposition in a spouted bed electrode (Martins et al 2012), and also for FBEs (Hutin and Coeuret 1977), whose process was modeled and simulated by Thilakavathi et al (2009). Furthermore, considering that the solid-phase conductivity depends on the statistical probability of particle shocks (Gabrielli et al 1994), expansion also will have an influence on the solid-phase conductivity, thus it would be expected that increasing the FBE expansion the solid-phase conductivity dropped.…”

“…The raise on applied current, besides of diminishing inactive zones and anodic dissolution in electrode interiors (Ruotolo and Gubulin 2005), should be performed Fig. 6 a AY against I and C 0 , E = 40 %, C s = 0.5 mol L -1 , b AY against E and C 0 , I = 6.0 A, C s = 0.5 mol L -1 , and c AY against C 0 and E. I = 6.0 A, C 0 = 500 mg L -1 , C s = 0.5 mol L -1 along with improvements on mass transport coefficient (Thilakavathi et al 2009) to avoid surpassing the limit current, since it could lead to lower CE act values. It is important to point out that raising C s did improve the process as it dwindled the difference between solid phase and liquid phase conductivities.…”