Leaching characteristics and environmental impact mechanisms of heavy metals and organic compounds from broken photovoltaic modules under freeze–thaw and acid–base conditions

This study investigated the leaching of heavy metals (Cu, Pb, Cd) and total organic carbon (TOC) from five photovoltaic (PV) components under freeze–thaw aging and acid–base exposure (pH 2–11). Results showed that acidic environments promoted Cu and Pb dissolution, with solder ribbons (SR) being the dominant source, where Pb peaked at pH 3 (1495.93 mg/kg). Potting adhesive (PA) exhibited high alkaline sensitivity; freeze–thaw aging significantly increased its TOC leaching by 93.75% at pH 11 (reaching 173.60 mg/L). Conversely, EVA encapsulant remained stable across all pH levels. Scanning electron microscopy confirmed acid-induced metallic corrosion and consistent morphological degradation on the solar cells’ rear surfaces. These findings reveal the combined environmental risks of climate aging and chemical exposure, highlighting the urgent need for SR detoxification and more durable encapsulation materials in PV waste management.