Recovery of silver from end-of-life silicon solar panels through a peroxymonosulfate-based advanced oxidation approach

Abstract

Silicon solar panels play an important role in the transition to a carbon-neutral energy system. Silver (Ag) is the core material of these panels, and due to surging production and increasing end-of-life (EoL) volumes, its scarcity raises growing concerns. We report a peroxymonosulfate (PMS)-based advanced oxidation process (AOP) for rapid Ag recovery from EoL crystalline silicon (c-Si) solar cells. Our findings showed that high-valent iron species (Fe(IV)) play a pivotal role in catalyzing PMS-based AOPs to generate singlet oxygen and enhance sulfate radical production via the Fe(II)/Fe(IV) redox cycle. Singlet oxygen and sulfate radicals served as the primary active species for silver oxidation extraction in the PMS/Fe²⁺ system, enabling complete (100%) Ag dissolution within 20 min from diverse types of c-Si cells. An integrated leaching and electrodeposition process recovered high-purity silver (>99%) without employing strong acids, cyanide, or volatile organic solvents. The energy consumption and chemical inputs were just 5% and 2% of those previously reported in the literature. This efficient and sustainable approach establishes AOP technology as a viable solution for resource recycling from EoL c-Si cells.