Organic Acid-Assisted Hydrothermal Leaching of Silver from End-of-Life Photovoltaic Panels
The aim of this study was the hydrothermal leaching of silver from waste monocrystalline silicon (m-Si) and polycrystalline silicon (p-Si) photovoltaic panel (PV) cells using organic acids, namely oxalic acid (OA) and citric acid (CA). Before leaching, two different pretreatment procedures were appl...
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2025-06-01
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| author | Eleni Kastanaki Rafaela Athanasiadou Anastasia Katsifou Apostolos Giannis |
| author_facet | Eleni Kastanaki Rafaela Athanasiadou Anastasia Katsifou Apostolos Giannis |
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| description | The aim of this study was the hydrothermal leaching of silver from waste monocrystalline silicon (m-Si) and polycrystalline silicon (p-Si) photovoltaic panel (PV) cells using organic acids, namely oxalic acid (OA) and citric acid (CA). Before leaching, two different pretreatment procedures were applied. First, the fluoropolymer backsheet was manually removed from the panel pieces and, then, the samples were subjected to high-temperature heating for the thermal degradation of the ethylene vinyl acetate (EVA) polymer. When removal by hand was not feasible, the second pretreatment procedure was followed by toluene immersion to remove the EVA and backsheet and separate the cells, glass, and films. After pretreatment, 4 M HCl leaching was applied to remove the aluminum layer from the cells. The remaining cells were subjected to hydrothermal leaching with organic acids to extract the silver. Several hydrothermal parameters were investigated, such as acid concentration (1-1.5-2 M), processing time (60-105-150 min), and temperature (150-180-210 °C), while the liquid-to-solid (L/S) ratio was fixed at 30 mL: 1 g, based on preliminary tests. Response surface methodology (RSM) was applied to optimize the hydrothermal leaching parameters. The optimized parameters were 210 °C, 95 min, 2 M CA or 210 °C, 60 min, 1 M OA. OA was more effective in Ag leaching than CA. The results were compared to HNO<sub>3</sub> leaching. The green leaching of silver from end-of-life PV panels with organic acids is an environmentally beneficial route. |
| format | Article |
| id | doaj-art-142a24b24b1d45dd90d09fea01077c78 |
| institution | Kabale University |
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| spelling | doaj-art-142a24b24b1d45dd90d09fea01077c782025-08-20T03:32:28ZengMDPI AGApplied Sciences2076-34172025-06-011512638310.3390/app15126383Organic Acid-Assisted Hydrothermal Leaching of Silver from End-of-Life Photovoltaic PanelsEleni Kastanaki0Rafaela Athanasiadou1Anastasia Katsifou2Apostolos Giannis3School of Chemical and Environmental Engineering, Technical University of Crete, University Campus, 73100 Chania, GreeceSchool of Chemical and Environmental Engineering, Technical University of Crete, University Campus, 73100 Chania, GreeceSchool of Chemical and Environmental Engineering, Technical University of Crete, University Campus, 73100 Chania, GreeceSchool of Chemical and Environmental Engineering, Technical University of Crete, University Campus, 73100 Chania, GreeceThe aim of this study was the hydrothermal leaching of silver from waste monocrystalline silicon (m-Si) and polycrystalline silicon (p-Si) photovoltaic panel (PV) cells using organic acids, namely oxalic acid (OA) and citric acid (CA). Before leaching, two different pretreatment procedures were applied. First, the fluoropolymer backsheet was manually removed from the panel pieces and, then, the samples were subjected to high-temperature heating for the thermal degradation of the ethylene vinyl acetate (EVA) polymer. When removal by hand was not feasible, the second pretreatment procedure was followed by toluene immersion to remove the EVA and backsheet and separate the cells, glass, and films. After pretreatment, 4 M HCl leaching was applied to remove the aluminum layer from the cells. The remaining cells were subjected to hydrothermal leaching with organic acids to extract the silver. Several hydrothermal parameters were investigated, such as acid concentration (1-1.5-2 M), processing time (60-105-150 min), and temperature (150-180-210 °C), while the liquid-to-solid (L/S) ratio was fixed at 30 mL: 1 g, based on preliminary tests. Response surface methodology (RSM) was applied to optimize the hydrothermal leaching parameters. The optimized parameters were 210 °C, 95 min, 2 M CA or 210 °C, 60 min, 1 M OA. OA was more effective in Ag leaching than CA. The results were compared to HNO<sub>3</sub> leaching. The green leaching of silver from end-of-life PV panels with organic acids is an environmentally beneficial route.https://www.mdpi.com/2076-3417/15/12/6383silicon PV panelsilverrecyclingorganic acidresponse surface methodology |
| spellingShingle | Eleni Kastanaki Rafaela Athanasiadou Anastasia Katsifou Apostolos Giannis Organic Acid-Assisted Hydrothermal Leaching of Silver from End-of-Life Photovoltaic Panels Applied Sciences silicon PV panel silver recycling organic acid response surface methodology |
| title | Organic Acid-Assisted Hydrothermal Leaching of Silver from End-of-Life Photovoltaic Panels |
| title_full | Organic Acid-Assisted Hydrothermal Leaching of Silver from End-of-Life Photovoltaic Panels |
| title_fullStr | Organic Acid-Assisted Hydrothermal Leaching of Silver from End-of-Life Photovoltaic Panels |
| title_full_unstemmed | Organic Acid-Assisted Hydrothermal Leaching of Silver from End-of-Life Photovoltaic Panels |
| title_short | Organic Acid-Assisted Hydrothermal Leaching of Silver from End-of-Life Photovoltaic Panels |
| title_sort | organic acid assisted hydrothermal leaching of silver from end of life photovoltaic panels |
| topic | silicon PV panel silver recycling organic acid response surface methodology |
| url | https://www.mdpi.com/2076-3417/15/12/6383 |
| work_keys_str_mv | AT elenikastanaki organicacidassistedhydrothermalleachingofsilverfromendoflifephotovoltaicpanels AT rafaelaathanasiadou organicacidassistedhydrothermalleachingofsilverfromendoflifephotovoltaicpanels AT anastasiakatsifou organicacidassistedhydrothermalleachingofsilverfromendoflifephotovoltaicpanels AT apostolosgiannis organicacidassistedhydrothermalleachingofsilverfromendoflifephotovoltaicpanels |