Electrolytic Removal of Phosphorus in Wastewater with Noble Electrode under the Conditions of Low Current and Constant Voltage

• Published in: International journal of electrochemical science 2013-06, Vol.8 (6), p.8557-8571
• Main Authors: Hong, KiHo, Chang, Duk, Bae, HyungSuk, Sunwoo, Young, Kim, JinHo, Kim, DaeGun
• Format: Article
• Language: English
• Subjects: Constant voltage; Electrode; Electrolysis; Phosphorus removal; Wastewater treatment
• ISSN: 1452-3981; 1452-3981
• DOI: 10.1016/S1452-3981(23)12908-7

Electrochemical experiment using three cathode materials such aluminum, iron, and copper operated constant voltage and low current conditions to evaluate the removal characteristics of phosphate ion in wastewater. The electrolysis experiments on synthetic wastewater with a higher concentration were also repeated 200 times for 10 minutes per each experiment under the bias voltage of 24V to estimate the stability of the copper electrode for a long time. When the copper electrode couple was used, by-products with green blue color such as copper hydroxide (Cu (OH)2) and copper phosphate (Cu3 (PO4)2) were formed on the surface of the anode and bubbles of hydrogen gas were formed on the surface of the cathode. The formation of copper hydroxide could contribute to removing phosphate because the hydroxyl ion (OH-) in the copper hydroxide can be exchanged with the phosphate ion. The surface of the copper anode was relatively clean without oxidation, while the surfaces of the aluminum and iron anodes were completely changed from the initial state with severe oxidation. With such change to the anode surface such as aluminum and iron anodes, the electrolysis performance would degrade very fast. In repeated electrolysis experiment using the copper electrode on synthetic wastewater with a higher concentration, the copper anode of 1mm thickness was sufficient to remove the phosphate which was more than 19g.