Enzymatic bioleaching of metals from printed circuit board

Jadhav, Umesh; Hocheng, H.

doi:10.1007/s10098-014-0847-z

Cited by 15 publications

(3 citation statements)

References 42 publications

(68 reference statements)

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“…Thus, it is clear that there is a critical need for e-waste recycling and material valorization, which strengthen the supply chain's sustainability and support the circular economy. Several pyro-and hydrometallurgical studies have been carried out to recover metals from PCBs [2,[18][19][20][21]. The application of pyrometallurgy for base metals recovery implies carrying out processes at higher temperatures, which provokes environmental concerns linked to gas emissions and slag generation [22].…”

Section: Introductionmentioning

confidence: 99%

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Bio-Assisted Leaching of Non-Ferrous Metals from Waste Printed Circuit Boards—Importance of Process Parameters

Vardanyan

Aâtach

et al. 2022

Metals

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The effect of varying process parameters during bio-catalyzed leaching of metals from end-of-life printed circuit boards (PCBs) was investigated. Fragmented PCBs (under 2 mm) were subjected to an indirect bioleaching in a stirred tank reactor while pulp density, pH and initial ferric iron content were varied. An iron oxidizing Acidithiobacillus ferrooxidans 61 microbial strain was used to generate the lixiviant through oxidizing Fe(II) to Fe(III). Chemically generated Fe(III) was tested as lixiviant under the same conditions as the biological one for comparative purposes. Cell enumeration during leaching and microscopic observations of the input and leached PCBs were conducted in parallel to shed light on the observed phenomena. The degree of bringing metals in solution was found to depend mainly on ferric iron concentration and pH. For the entire duration being always kept as 24 h, substantial portion of Cu (~87%) was extracted respectively at 1% pulp density (PD), 15.5 g/L Fe3+ and pH 1. For Zn and Ni, nearly 100% recovery was observed at 5% PD, 18 g/L Fe3+ and pH 1.1. The achieved results offer possibilities for further studies at higher pulp density, to ultimately render the bioleaching approach as enabling economical and environmentally friendly technology for urban mining of non-ferrous metals.

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Section: Introductionmentioning

confidence: 99%

“…Pyrite is used as an alternative source of iron in mineral processing industries, acting as an energy source for the growth of iron oxidizers. However, the majority of the studies deals with very low pulp densities and report low metal extraction efficiency and slow metal extraction rates [19,23,37,39,40].…”

Section: Introductionmentioning

confidence: 99%

Bio-Assisted Leaching of Non-Ferrous Metals from Waste Printed Circuit Boards—Importance of Process Parameters

Vardanyan

Aâtach

et al. 2022

Metals

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“…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].…”

Section: Introductionmentioning

confidence: 99%

Effect of Graphite on Copper Bioleaching from Waste Printed Circuit Boards

et al. 2020

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The efficient extraction of copper as a valuable metal from waste printed circuit boards (WPCBs) is currently attracting growing interest. Here, we systematically investigated the impact of bacteria on the efficiency of copper leaching from WPCBs, and evaluated the effect of graphite on bioleaching performance. The HQ0211 bacteria culture containing Acidithiobacillus ferrooxidans, Ferroplasma acidiphilum, and Leptospirillum ferriphilum enhanced Cu-leaching performance in either ferric sulfate and sulfuric acid leaching, so a final leaching of up to 76.2% was recorded after 5 days. With the addition of graphite, the percentage of copper leaching could be increased to 80.5%. Single-factor experiments confirmed the compatibility of graphite with the HQ0211 culture, and identified the optimal pulp density of WPCBs, the initial pH, and the graphite content to be 2% (w/v), 1.6, and 2.5 g/L, respectively.

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