Biohydrometallurgy as an environmentally friendly approach in metals recovery from electrical waste: A review

Abstract

Nowadays, large amount of municipal solid waste is because of electrical scraps (i.e. waste electrical and electronic equipment) that contain large quantities of electrical conductive metals like copper and gold. Recovery of these metals decreases the environmental effects of waste electrical and electronic equipment (also called E-waste) disposal, and as a result, the extracted metals can be used for future industrial purposes. Several studies reported in this review, demonstrated that the biohydrometallurgical processes were successful in efficient extraction of metals from electrical and electronic wastes. The main advantages of biohydrometallurgy are lower operation cost, less energy input, skilled labour, and also less environmental effect in comparison with pyro-metallurgical and hydrometallurgical processes. This study concentrated on fundamentals and technical aspects of biohydrometallurgy. Some points of drawbacks and research directions to develop the process in the future are highlighted in brief.

Circular Economy and the Fate of Lithium Batteries: Second Life and Recycling

“…[23] This technique was successfully demonstrated in the extraction from ores and in the treatment of waste electrical and electronic equipment (WEEE) to recover critical metals from printed circuit boards or electrical products like rare-earth elements, e.g., Au, Cu, Al, Pb, Ni, [24] but also other highly toxic and environmentally hazardous elements, such as As, Cd, Cr(VI), Be. [25] It consists of a bioleaching step that uses acidophilic microorganisms, which are naturally able to dissolve metals from the waste. Three kinds of microorganisms can be typically used to convert metals in the soluble ionic form, namely, 1) autotropic and 2) heterotrophic bacteria and 3) heterotrophic fungi.…”

“…Heterotrophic microorganisms often used in bioleaching are, for example, filamentous microfungi like Aspergillus, Penicillum species, and Bacillus bacteria. [25] The performances of biohydrometallurgy processes are affected by several operating parameters, which require proper optimization. [23e] Some of them are concerned with the microorganism metabolic activities, i.e., 1) temperature, which should be not too high to favor their accumulation and survival; 2) the nutrients, which may change depending on the types of microbes (e.g., C. violaceum for gold extraction) and whose concentration is critical for the metal biorecovery, especially in case of glycine and some salts as sodium chloride and magnesium sulfate; 3) the redox couples, such as elemental sulfur and particularly Fe ions, which may improve bacterial growth; and 4) pH of the environment and concentration of dissolved O 2 , which are critical for cell population increase and for aerobic microorganisms' breathing.…”

Microstructure and properties analysis of the brazing alloy prepared from recycled E-waste

“…Mo, Sb, and rare and precious metals, such as, Au and Ag ( Jiang et al, 2016 ), have a comparatively low concentration. The research reports that a number of methods of recovering metal from circuit boards in China and abroad are dominated by physical separation extractive techniques such as magnetic separation, electrical separation, eddy current separation ( Zheng et al, 2016 ; Gu et al, 2019 ), pyrometallurgy ( Park and Kim, 2019 ; Habibi et al, 2020 ; Yue et al, 2021 ), hydrometallurgy ( Díaz-Martínez et al, 2019 ), Bio-hydrometallurgy ( Gu, 2016 ), and other extractive techniques. Due to the characteristics of e-waste, including its large quantity, complicated constituents, great harm, high potential value, and difficulty in treatment ( Cao et al, 2003 ; Zhu et al, 2018 ), the recovery of valuable metals is the focus of attention for metal resource recovery from e-waste.…”

Box-Behnken Optimization and Theoretical Study for Copper Recovery from Scrap Laptop Computer Printed Circuit Board by Malonic Acid and Hydrogen Peroxide

“…Although Cu is sourced mainly from primary mining of ore deposits, secondary mining from sources like printed circuit boards (PCBs) is gaining attention as it is a more environmentally friendly option than primary mining [4]. Popular methods employed for secondary Cu recovery include pyrometallurgy [5], hydrometallurgy [6], biohydrometallurgy [7], and electrochemical recovery [8].…”