Extraction of Selected Metals from Waste Printed Circuit Boards by Bioleaching Acidophilic Bacteria

Abstract

Technological innovations and increased demand for electronic devices resulted in production of more and more waste with high metal content. Worldwide, 50 million tons of WEEE (Waste from Electrical and Electronic Equipment) are generated each year. Given the metal content present in electrical waste (e-waste), it is considered to be an urban mine and, if properly treated, can serve as an alternative secondary source of metals. Waste printed circuit boards (WPCBs) that constitute approx. 3-5% of WEEE by weight are of particular importance. They contain, on average, 30-40% of metals by weight, with higher purity than in minerals. With environmental and economic benefits in mind, increasing attention is being paid to the development of processes to recover metals and other valuable materials from WPCBs. The research presented in the article aimed at assessing the usefulness of the biotechnological method for leaching of selected metals from e-waste. The results indicate that it is possible to mobilize metals from WPCBs using microorganisms such as Acidithiobacillus ferroxidans bacteria.