Evaluation of environmental footprint: Life Cycle Assessment of Laboratory-scale thermal and chemical processes used for materials extraction from waste silicon solar panels

Abstract

This study explores recycling methods for recovering valuable components from discarded silicon solar panels, focusing on high-temperature thermal treatment and chemical processing with toluene as a solvent. The environmental impacts of these methods were comprehensively investigated using a detailed Life Cycle Assessment (LCA). During thermal treatment, emissions were analyzed by adsorbing them onto quartz filter paper. XRF, TGA-DTG, and FT-IR analyses confirmed the presence of emitted elements, including Si, C, O, B, Na, Mg, Ca, K, P, S, Cl, and Fe, some of which could pose environmental and health risks. The LCA results revealed significant environmental trade-offs between the two approaches. The chemical method demonstrated superior material recovery and solvent management capabilities but had a higher carbon footprint and fossil fuel potential (5.42kg-eq) compared to thermal treatment (0.235kg-eq). Thermal treatment showed lower impacts on climate change, fossil fuel potential, water consumption, ecotoxicity, human toxicity, and particulate matter production but had more pronounced effects on ozone depletion and land use. Choosing between methods depends on specific environmental priorities. To achieve sustainable disposal and material recovery of solar panels, broader considerations including carbon emissions, resource utilization, and waste management strategies are crucial. This study provides insights to promote environmentally responsible practices in solar panel recycling.