A novel approach for the efficient recovery of lead from End-of-Life Silicon Photovoltaic modules

Abstract

There is an urgent need to develop a technology for recycling solar waste that will soon be generated in heaps. While various studies focused on recovering valuable materials from waste silicon solar panels, there has been minimal emphasis on the treatment of toxic substance lead. Thus, the current study proposed a novel approach to treat the harmful component of lead by recovering it in its less toxic form as PbO having commercial applications. This is accomplished through optimization of a three-step process (i) selective leaching of the top layer from interconnect, (ii) extraction of lead from the leachate by precipitation, and (iii) calcination. The lead recovery at each stage was analyzed by characterization techniques viz. ICP-OES, XRD, SEM, and a unique attempt has been made to optimize the precipitation process by constructing an Eh vs. pH diagram. The efficient leaching of lead from interconnects was observed with 1.5 M nitric acid for 5 min at 60 °C which was followed by precipitation from the leachate with 1.5 M NaOH solution and finally calcination at 500 °C for 2 h to obtain lead monoxide. The feasibility of the optimized process at a larger scale was carried out with 200 g (60-cell panel) of copper ribbons.