Effect of Voltage on the Treatment of Cyanide Wastewater by Three-dimensional Electrode

Abstract

The effects of applied voltage on cyanide wastewater treatment by three-dimensional electrodes were primarily examined. The main electrodes were produced from self-made coal-based electrode materials, and activated carbon was used as a particle electrode to treat cyanide wastewater. Changes in the concentration of ions in wastewater were determined and analyzed through Scanning Electron Microscopy and Energy Dispersive Spectroscopy. Results show that voltage significantly affects wastewater treatment via the three-dimensional electrodes. In particular, the removal rate of the ions in wastewater increases as voltage increases. The reaction mechanism of the three-dimensional electrodes also varies at different voltages. At 1 V, the reaction mechanism of the three-dimensional electrodes involves electro-adsorption. The removal rates of CNT, Cu, Zn, SCN−, and CN− in wastewater are 31.81%, 53.04%, 36.11%, 29.05%, and 29.05%, respectively. The reaction mechanism of the three-dimensional electrodes includes electro-adsorption and enrichment precipitation when voltage is increased to 2 V. The three-dimensional electrode plays a significant role in electrolytic deposition when voltage is further increased to 3 and 4 V. Cu, Zn, and other heavy metal ions are reduced on the cathode and on the particle electrode surface, and the removal rates of CNT, Cu, Zn, SCN−, and CN− in wastewater are 93.94%, 95.22%, 97.23%, 99.38%, and 94.93%, respectively.