Release of metal pollutants from corroded and degraded thin-film solar panels extracted by acids and buried in soils

Abstract

Abstract Thin-film solar panels (TFSPs) are widely used in integrated photovoltaic and solar power systems because of their perfect photovoltaic characteristics and ductility. These panels differ from the traditional silicon-based solar panels, in that the metal thin-film layers contain some potentially toxic metals such as zinc (Zn), copper (Cu), nickel (Ni), gallium (Ga), lead (Pb), indium (In) and chromium (Cr). In this study, we examined the environmental pollution that might be caused by disposing of TFSP as domestic trash at the end of their useful life. We used acid extract to simulate metal leaching toxicity and acidic corrosion, and then buried TFSPs in three types of soils to determine if metals might be released into the soil. Our results indicated that the amounts of dissolved metals increased as both the contact time with the acid and the acid concentration in the solution increased during nitric acid extraction. Heavy metals were released from TFSPs in the burial experiment, and the rates of metal release changed with variations in both the amounts of TFSPs in the soil and the soil properties. The increased concentrations of heavy metals such as Zn, Cu, Ni, Ga, Pb, In and Cr in soil samples were correlated to the amounts of TFSPs added. The results of this study confirmed that, when buried, TFSPs polluted the soil.