Metal Recovery from Wastewater with an Electrochemical Method

Abstract

This article describes the development of an experimental project to enhance undergraduate chemical engineering students’ experience in reaction engineering and wastewater treatment.  The project was implemented in a senior-level laboratory course at Clarkson University. Students in the course performed the electrolysis experiments to reduce toxic metal ions in wastewater from an initial concentration of 50-250 parts per million (ppm) to a low level acceptable for discharge by U.S. Environmental Protection Agency (EPA) regulations.  By measuring the concentration changes of the metal ion at various controlled anode-to-cathode cell voltages, temperatures, and water recirculation rates, students determined the reaction rate constant, its activation energy, and the effect of mass transport of metal ions on the rate of electrodeposition reaction.  By measuring the amount of metal recovered and total electric charges used in the electrolysis, students calculated the current efficiency and energy requirement of the process and compared the results to those reported in the open literature.  The electrolysis experiment is safe for students and instructors.  The project is suitable for use as a short experiment to be completed in one six-hour lab period. It can also be assigned to students taking the lab course as a mini-thesis project over a period of three to four weeks.