Biohydrometallurgical methods and the processes involved in the bioleaching of WEEE

Abstract

The obsession toward the latest electronics and electrical goods has led to the generation of undesirable quantities of Waste Electrical and Electronic Equipments termed as electronic wastes (e-wastes). E-wastes, especially the printed circuit boards, are rich in their metal concentration and are considered as secondary resources for urban mining. The management of the metallic portion of these wastes is achieved through established physical, chemical, and biological treatment technologies. Biohydrometallurgy is a significant technology to address the issue in an eco-friendly mode. The different processes of biohydrometallurgy include bioleaching, bioflocculation, bioprecipitation, biosorption, biooxidation, and bioreduction. Bioleaching plays a vital role in the dissolution of metals from the solid matrix into the leaching solution using microorganisms. The different methods of bioleaching to accomplish metal recovery from e-waste are one-step bioleaching, two-step bioleaching, and spent medium bioleaching. The method to be selected depends on several growth and process factors to be successfully implemented. This chapter focuses on the methods of bioleaching and the processes involved in each of these methods to opt the most appropriate one for efficient metal recovery. Studies on biohydrometallurgy would confront the glitches involved in e-waste disposal and recycling in a sustainable manner. © 2021 Elsevier Inc. All rights reserved.