Institutional Repository
Technical University of Crete
Technical University of Crete
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| URI: | http://purl.tuc.gr/dl/dias/9022C4D1-E82A-4A43-8B5F-F11F68649190 | ||
| Year | 2025 | ||
| Type of Item | Diploma Work | ||
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| Bibliographic Citation | Anastasia Katsifou, "Effect of organic solvents on the leaching of valuable elements from photovoltaic panels", Diploma Work, School of Chemical and Environmental Engineering, Technical University of Crete, Chania, Greece, 2025 https://doi.org/10.26233/heallink.tuc.104158 | ||
| Appears in Collections |
The rapid intensification of climate change has accelerated the transition toward environmentally friendly energy sources, with Renewable Energy Sources (RES) becoming a central pillar of energy transition strategies. Since 2000, electricity generation from photovoltaic (PV) systems has experienced significant growth, resulting in the widespread installation of first-generation panels, primarily based on monocrystalline and polycrystalline silicon. Given the average service life of a PV panel (20–25 years), a considerable volume of PV waste is expected in the coming decades, highlighting the urgent need for recycling technologies aligned with circular economy principles. This thesis focuses on the hydrothermal leaching of silver (Ag) from silicon-based end-of-life PV panels, using a mild organic acid, specifically oxalic acid (OA). Despite its low concentration in PV cells, silver is a valuable metal with high market value, which renders its recovery economically important. The experimental procedure included initial thermal and chemical pretreatment of the cells (removal of EVA and aluminum layers), followed by hydrothermal leaching under controlled conditions. The main parameters investigated were oxalic acid concentration (1–2 M), temperature (150–210 °C), and residence time (60–150 min), while the liquid-to-solid (L/S) ratio was kept constant at 30:1 ml/g. Process optimization was performed using Response Surface Methodology (RSM) with a Box–Behnken experimental design. Results indicated that acid concentration was the most influential factor in Ag recovery, while elevated temperatures further enhanced the leaching efficiency. Optimal leaching conditions were determined as 210 °C, 1 M OA, and a reaction time of 60 min, achieving high silver recovery yields. In comparison, leaching with strong inorganic acid (65% HNO₃) exhibited significantly higher efficiency, underscoring the need for further optimization of environmentally benign methods. Overall, this approach contributes to the development of green technologies for the recovery of critical metals from PV waste, promoting the sustainability and efficiency of RES life cycles.
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