Lead leaching and electrowinning in acetic acid for solar module recycling

It is imperative to recover lead (Pb) contained in end-of-life solar modules. In this paper, a two-step leaching and electrowinning process using acetic acid is investigated for Pb recovery. Acetic acid with hydrogen peroxide can dissolve Pb quickly and, under some conditions, in a matter of minutes. Pb electrowinning has been successfully demonstrated from aqueous solutions of 0.009 M lead(II) acetate with 0-10% v/v acetic acid. Pb-containing deposits are found on both the copper cathode and graphite anode. X-ray diffraction, energy-dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy confirm the presence of metallic Pb and Pb(II) oxide (PbO) co-deposits on the cathode. There is also the formation of lead subacetate on the cathode under certain conditions. On the anode, the deposit consists of lead(IV) oxide and superoxide (PbO2 and Pb1-xO2). A Pb re-covery rate of 99% is achieved in 0.009 M lead(II) acetate solutions with 10% v/v acetic acid by applying a reduction potential of either -0.8 V or -1.0 V versus the silver/silver chloride reference electrode for 24 h. Pb leaching with acetic acid is also demonstrated from milled silicon solar modules.

Automated summary

This paper investigates a two-step leaching and electrowinning process using acetic acid for the recovery of lead (Pb) from end-of-life solar modules. It is found that acetic acid with hydrogen peroxide can dissolve Pb quickly, in a matter of minutes under certain conditions. The study demonstrates successful Pb electrowinning from aqueous solutions of lead(II) acetate with 0-10% v/v acetic acid. The presence of metallic Pb and Pb(II) oxide co-deposits on the cathode, as well as lead subacetate and lead(IV) oxide deposits on the anode, is confirmed through various analytical techniques.