Bioleaching of Selected Metals from Waste Printed Circuit Boards by Fungs

Abstract

The growing demand for non-ferrous metals over the last centuries has resulted in constant extraction of natural resources - in case of many crucial and most widely used raw materials, accessible and high-quality deposits are already close to being depleted. Waste electrical and electronic equipment (WEEE) constitutes a rich, secondary source of metals, the amount of which in the EU is increasing every year. In order to increase resource efficiency and contribute to a circular economy, it is necessary to improve the processing and recycling of waste electrical and electronic equipment at the end of an electronic lifetime. The choice of a suitable method of processing this waste is vital due to the complex and materially diverse composition of WEEE. Waste printed circuit boards (WPCBs) that consti - tute approx. 3-5% of WEEE by weight are of particular importance from both environmental and economic point of view. The article investigates the recovery of Cu, Ag and Al from WPCBs using an industrial fungal strain of Aspergillus niger. The bioleach - ing process was carried out using 3 methods (one-step, two-step and spent medium) in an incubator with shake depending on the contact time and pulp density. 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 mobilise metals from the WPCBs using microorganisms.