Recovery of Metals from Printed Circuit Boards (PCBs) Using a Combination of Hydrometallurgical and Biometallurgical Processes

Document Type: Original Research Paper


Department of Biotechnology, School of Bioengineering, SRM University, Kattankulathur, India


Printed circuit boards (PCBs) are one of the most important components of electronic equipment and encompass a variety of metals, including the majority of the valuable metals, and also most of the toxic components in e-waste. The objective of the present work proposes an integrated (hybrid) method for the recovery of copper (Cu), nickel (Ni) and zinc (Zn) from waste PCBs using a combination of biometallurgical (biological) and hydrometallurgical (chemical) processes. The recovery was effected using the combination of Acidithiobacillus ferrooxidans and 2 M HNO3. The leaching of metals was experimented using inorganic acid, bacteria and the integration of both acid and bacteria. From the initial experiments, it was observed that the percentage of nickel, copper and zinc solubilised into leaching solution from the actual PCB basically decreased with the increase in the concentration of e-waste from 10g/L to 100g/L. The hybrid method was compared against the individual chemical and biological methods and proved to be a better method than the other two, being rapid, efficient, economical and eco-friendly.