Recovery of palladium from waste fashion items through food waste by-products

Abstract

Palladium is a non-toxic platinum group metal indispensable for several industrial applications. It is among the 44 endangered elements; hence, its recycling from secondary sources is crucial. Waste plated metal wires from the fashion industry are an important waste stream for this precious metal. We propose a sustainable route for Pd recovery where palladium peels off in its metallic state in a single-step, room-temperature process. At the same time, readily oxidizable base metals are leached under very mild conditions using a green oxidant, hydrogen peroxide, and lactic acid, a food chain byproduct. This strategy is chemically rational, cost-effective, and environmentally friendly. The recovered Pd was successfully recycled to fabricate source and drain electrodes in organic field-effect transistors. Waste wires, recovered palladium flakes, and e-beam evaporated Pd electrodes were characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy to examine their morphology and (surface) chemical composition.