Bio-Assisted Leaching of Non-Ferrous Metals from Waste Printed Circuit Boards—Importance of Process Parameters
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 we...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-12-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/12/12/2092 |
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| author | Arevik Vardanyan Narine Vardanyan Mohamed Aâtach Pierre Malavasi Stoyan Gaydardzhiev |
| author_facet | Arevik Vardanyan Narine Vardanyan Mohamed Aâtach Pierre Malavasi Stoyan Gaydardzhiev |
| author_sort | Arevik Vardanyan |
| collection | DOAJ |
| description | 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 <i>Acidithiobacillus ferrooxidans</i> 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 Fe<sup>3+</sup> and pH 1. For Zn and Ni, nearly 100% recovery was observed at 5% PD, 18 g/L Fe<sup>3+</sup> 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. |
| first_indexed | 2024-03-09T16:06:00Z |
| format | Article |
| id | doaj.art-46d1d32b9b6d446780e450c38f18f0a6 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-09T16:06:00Z |
| publishDate | 2022-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-46d1d32b9b6d446780e450c38f18f0a62023-11-24T16:40:47ZengMDPI AGMetals2075-47012022-12-011212209210.3390/met12122092Bio-Assisted Leaching of Non-Ferrous Metals from Waste Printed Circuit Boards—Importance of Process ParametersArevik Vardanyan0Narine Vardanyan1Mohamed Aâtach2Pierre Malavasi3Stoyan Gaydardzhiev4Department of Microbiology, SPC “Armbiotechnology” of the National Academy of Sciences of Armenia, 14 Gyurjyan Str., Yerevan 0056, ArmeniaDepartment of Microbiology, SPC “Armbiotechnology” of the National Academy of Sciences of Armenia, 14 Gyurjyan Str., Yerevan 0056, ArmeniaGeMMe—Minerals Engineering and Recycling, Faculty of Applied Sciences, ArGEnCo Department, University of Liege, Allée de la découverte 9, Bât. B52/3, Sart-Tilman, 4000 Liege, BelgiumGeMMe—Minerals Engineering and Recycling, Faculty of Applied Sciences, ArGEnCo Department, University of Liege, Allée de la découverte 9, Bât. B52/3, Sart-Tilman, 4000 Liege, BelgiumGeMMe—Minerals Engineering and Recycling, Faculty of Applied Sciences, ArGEnCo Department, University of Liege, Allée de la découverte 9, Bât. B52/3, Sart-Tilman, 4000 Liege, BelgiumThe 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 <i>Acidithiobacillus ferrooxidans</i> 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 Fe<sup>3+</sup> and pH 1. For Zn and Ni, nearly 100% recovery was observed at 5% PD, 18 g/L Fe<sup>3+</sup> 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.https://www.mdpi.com/2075-4701/12/12/2092printed circuit boards (PCB)iron oxidizing bacteriadouble-stage bioleachingmetal extractionpulp densityleaching yield |
| spellingShingle | Arevik Vardanyan Narine Vardanyan Mohamed Aâtach Pierre Malavasi Stoyan Gaydardzhiev Bio-Assisted Leaching of Non-Ferrous Metals from Waste Printed Circuit Boards—Importance of Process Parameters Metals printed circuit boards (PCB) iron oxidizing bacteria double-stage bioleaching metal extraction pulp density leaching yield |
| title | Bio-Assisted Leaching of Non-Ferrous Metals from Waste Printed Circuit Boards—Importance of Process Parameters |
| title_full | Bio-Assisted Leaching of Non-Ferrous Metals from Waste Printed Circuit Boards—Importance of Process Parameters |
| title_fullStr | Bio-Assisted Leaching of Non-Ferrous Metals from Waste Printed Circuit Boards—Importance of Process Parameters |
| title_full_unstemmed | Bio-Assisted Leaching of Non-Ferrous Metals from Waste Printed Circuit Boards—Importance of Process Parameters |
| title_short | Bio-Assisted Leaching of Non-Ferrous Metals from Waste Printed Circuit Boards—Importance of Process Parameters |
| title_sort | bio assisted leaching of non ferrous metals from waste printed circuit boards importance of process parameters |
| topic | printed circuit boards (PCB) iron oxidizing bacteria double-stage bioleaching metal extraction pulp density leaching yield |
| url | https://www.mdpi.com/2075-4701/12/12/2092 |
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