Silver Recovery from End-of-Life Photovoltaic Panels Based on Microbial Fuel Cell Technology

Abstract

The solar energy sector has grown rapidly in the past decades, addressing the issues of energy security and climate change. Many photovoltaic (PV) panels that were installed during this technological revolution, have accumulated as waste and even more are nearing their End-of-Life (EoL). Based on circular economy, a new hydrometallurgical process has been proposed for the management of the EoL PVs. This results in a chemical extract containing 0.7% w/w Ag, along with various other metals. This study investigates the MFC technology as an alternative method for valuable metal recovery from the chemical extract of PV panels. Moreover, metal recovery from the chemical extract is compared with the individual recoveries obtained using corresponding synthetic solutions. The results indicated that silver was completely recovered from the synthetic and the real chemical extract, with a rate of ~ 82 and ~ 32 μmol/h, respectively. The difference is attributed to the simultaneous reduction of other heavy metals in amorphous compounds, hindering the silver reduction kinetics and leading to a gradual electrode passivation. Nevertheless, silver can be 100% retrieved from the chemical extract, with a purity of 68–96% w/w (average 86% w/w), in crystal (face center cube) structure, containing minor metal impurities. Graphical Abstract: [Figure not available: see fulltext.]