Scientists from the University of Camerino have developed a novel way of extracting silver from end-of-life solar cells.

Solar cells use various metals, such as aluminum, steel, copper, zinc, and silver. While aluminum and silver are easily recoverable, copper and silver can be difficult to obtain.

By combining hydrometallurgical and electrochemical processes, the scientists have reportedly recovered pure silver with an efficiency of 98%.

According to the university’s Environmental Technology & Innovation paper, “Conventional metal extraction techniques, such as open-pit mining, can inflict substantial harm on the environment and neighboring ecosystems. Therefore, employing a metal recovery process based on industrial wastes can mitigate the environmental impact of metal production.”

The process of recovering the metal involves the use of base-activated persulfate along with ammonia.

“A chemometric approach based on experimental design was used to find the best conditions for the leaching process based on a combined base-activated persulfate and ammonia system. A novel method known as electrodeposition-redox replacement was used to recover it. A remarkable pure silver recovery of 98.7±1.4 % was achieved,” the report said.

The study aimed to develop a highly selective process for leaching silver particles and electrodepositing them through environmentally friendly electrochemical methods.

A combined base-activated persulfate and ammonia system was tested in the leaching process to address this issue. Persulfate acts as an oxidizing agent, and its strong oxidation properties can be activated using a strong base (NaOH).

The researchers conducted an experiment consisting of varying parameters for the leaching process, and the electrodeposition-redox replacement (EDRR) approach using a pulsed electrodeposition method was deemed successful.

“Notably, this approach proves to be selective in its recovery of silver and does not require any chemical addition. This unique feature renders this methodology competitive compared to conventional processes,” the report said.

In 2023, engineers at the University of New South Wales introduced a novel method to recycle solar panels and efficiently recover valuable materials, particularly silver. The patented process has been designed to streamline the sorting of component materials, a crucial step in achieving efficient photovoltaic panel recycling.

Earlier, scientists at the Fraunhofer Institute of Solar Energy developed a new laser technique to reduce the amount of silver used to produce solar panels and achieve maximum module efficiency using a thin aluminum foil.