Bioleaching of copper from metal concentrates of waste printed circuit boards by a newly isolated Acidithiobacillus ferrooxidans strain Z1

Abstract

The goal of this study is to determine the potential of Acidithiobacillus ferrooxidans strain Z1 in bioleaching of metal concentrates of waste printed circuit boards (PCBs). The influences of initial pH, initial Fe(II) concentration, metal concentrates dosage, inoculation quantity and particle size on the bioleaching process were investigated and optimum conditions were determined. The results showed that 92.57 % copper leaching efficiency was achieved within 78 h in a two-step process, and 85.24 % aluminum and 95.18 % zinc were leached out after 183 h under the optimum conditions of initial pH 2.25, initial Fe(II) 9 g/L, metal concentrates dosage 12 g/L, inoculation quantity 10 % and particle size 0.178-0.250 mm. It demonstrated that metals could be efficiently leached from metal concentrates by Acidithiobacillus ferrooxidans Z1 and the bioleaching period was reduced 81-78 h. Therefore, the strain Acidithiobacillus ferrooxidans Z1 could be suggested as a potential strain to bioleach metals from metal concentrates of waste PCBs.

A Bioleaching Process for Sustainable Recycling of Complex Structures with Multi-Metal Layers

“…A number of studies have been published on the selective recovery of base and precious metals from other types of ewaste, such as PCBs, using direct bioleaching to solubilize base metals. Generally, relatively high to high base metal recovery rates (75 to >99%) have been achieved in the laboratory using Fe 2+ -and/or S-oxidizing prokaryotes [40][41][42][43][44][45][46][47][48][49][50][51][52][53]. However, particularly when multiple base metals were targeted for extraction, the metal recovery rates could be significantly lower (mostly 50-60%) [51,53,54].…”

Effect of Graphite on Copper Bioleaching from Waste Printed Circuit Boards

“…When continuing to increase pulp density to 10%, copper-leaching percentage was only 35%. High WPCB dosage resulted in lower copper extraction partly due to limitations in air distribution and oxygen mass transfer, which inhibited the oxidation efficiency of Fe 2+ by the bacteria [8,22,23]. In addition, copper concentration increased with WPCB dosage.…”

“…Therefore, it has been widely used to recover valuable metals from low-grade minerals, and to remove heavy metals from various sources such as sludge, fly ash, polluted soil, and sediment [2][3][4][5][6]. Furthermore, bioleaching was found to be a viable method to leach metals from electronic waste, such as used batteries and waste printed circuit boards (WPCBs) [7,8].…”

Evaluation of Aspergillus niger and Penicillium simplicissimum for their ability to leach Zn–Ni–Cu from waste mobile phone printed circuit boards

“…In the twenty-first century, E-wastes are known as a global concern, and toxic substances such as heavy metals can permeate into the groundwater and soil, which extremely threatens humans' health. Moreover, compared to traditional municipal waste, E-wastes contain valuable metals that can be recovered and reused, which brings about the evaluation of the recovery becomes remarkably crucial [6,7].…”

“…Biohydrometallurgical processes are low cost, environmentally friendly, and do not require skilled labor. In addition, they are efficient for low-grade ores and wastes [2,7]. Bioleaching is defined as an interaction between metals and microorganisms that can transfer metals to the liquid phase [4]; microorganisms (bacteria or fungi) produce organic or inorganic acids which solute metals [2].…”