Electrochemical adsorption of precious metal from electronic wastes based on adsorbent electroplating membrane

Abstract

The increased demand for various electronic products causes a shortage of precious metals, as limited resources. As the electronics industry market expands, e-waste generated is attracting attention as a sustainable source of valuable metals. However, separating and refining valuable metals from electronic waste is expensive, and process development for commercialization is also tricky. Accordingly, a new porphyrin-based porous polymer adsorbent called COP-180 has recently been developed to utilize the adsorption method, and a selective adsorption mechanism for gold, especially among valuable metals, has been introduced. In this study, an adsorbent membrane is fabricated by electroplating COP-180 with high gold selectivity and cost efficiency on a membrane filter to investigate the process, efficiency, and plating stability for electrochemical gold adsorption. In this system, silver nanowires, conductive materials, were plated on the membrane to achieve an adsorption efficiency of 70% within 6 hours compared to the powder form due to high conductivity and current density than other electrodes. In addition, COP-180 maintained excellent gold adsorption properties even after fabrication as a membrane (1.38 g Au/g COP-180). The gold solution was produced by the desorption process of the previous study, and the surface stability and adsorption efficiency were confirmed by recycling the membrane. In addition, an economic evaluation was conducted, and the developed process can be used as a sustainable resource circulation process within the electronics industry regarding adsorption time and reuse.