How to Recover 98% Silver from Solar Panels

A collaborative team of chemists, metallurgists, and engineers from various institutions has pioneered an efficient method to extract silver from decommissioned solar panels. Their study, published in Environmental Technology & Innovation, details this innovative approach.

As the global transition to renewable energy accelerates, particularly with the adoption of solar power, managing the disposal of used solar panels has become a pressing issue. While materials such as iron, steel, and aluminum in the panels are relatively straightforward to recycle, retrieving silver from the electrical circuits within these panels has posed significant challenges.

In their recent work, a team based in Italy has developed a practical technique for recovering silver from old solar panels. Their method involves the use of base-activated persulfate combined with ammonia. In this process, persulfate serves as the oxidizing agent, facilitating the separation of silver while forming copper oxide, which prevents the leaching of copper.

The researchers meticulously tested various ammonia concentrations and other conditions, such as stirring speed and temperature, to find the optimal setup. They discovered that a concentration of 0.5 M ammonia and 0.2 mol per liter of potassium persulfate, with a one-hour reaction time, successfully separated 85% of the silver from the sample.

Further enhancement of the process through electrodeposition-redox replacement raised the recovery rate to an impressive 98.7%. This was confirmed using a scanning electron microscope, which verified the purity of the extracted silver particles.