Electrodeposition of copper and lead on palm shell activated carbon in a flow-through electrolytic cell

Palm shell is an abundant solid waste generated from the palm oil industry in Malaysia. Activated carbon obtained from palm shells has good electrochemical properties and may be used as a working electrode material to remove ions of heavy metals from industrial wastewaters. Results are presented on the electrodeposition of copper and lead ions onto palm shell activated carbon electrodes in terms of current efficiency (%). The study was carried out in a continuous packed-bed electrochemical cell. The effects of applied current, solution flow rate, pH of the feed, and presence of complexing agents namely malonic and boric acids on the overall current efficiency were investigated. The results showed that the current efficiency increases with an increase of the flow rate. The application of more negative current to the electrolytic cell resulted in the decrease of current efficiency values. Presence of malonic acid resulted in a relative increase of the current efficiency compared to the single metal system for both pH 3 and 5. The presence of boric acid also resulted in a similar overall increase of the current efficiency. The concentration of the solution leaving the cell strongly depended on the current values applied as well as the solution flow rate; for copper it varied between 0–20 mg/L, and for lead it was between 0–5 mg/L from an inlet value of 50 mg/L for both ions.