Selective Gold Recovery from Waste PCBs with Polyamide 6 Fishing Line Adsorptive Membrane

Abstract Description: Printed circuit boards (PCBs) are a significant source of waste electrical and electronic equipment (WEEE), with gold being the most valuable component due to its high industrial demand and growing scarcity. This study presents a sustainable approach for gold ion recovery using innovative polyamide 6 (PA6) fishing line adsorptive membranes, fabricated via phase inversion. Recovery performance was evaluated under varying pH conditions, comparing membranes derived from commercial PA6 powder and PA6 fishing lines. At pH 2, the adsorptive membranes from commercial PA6 powder achieved a recovery efficiency of 97.38% with a capacity of 8.03 mg/g, while those from PA6 fishing lines exhibited a recovery of 91.13% with a capacity of 7.73 mg/g. At pH 7, the recovery efficiencies were 64.29% (capacity: 4.25 mg/g) for PA6 powder membranes and 64.87% (capacity: 4.27 mg/g) for fishing line membranes. Recovery was significantly higher under acidic conditions, confirming the pH-dependent nature of gold ion adsorption. Notably, the performance differences between the two adsorptive membrane types were minimal, demonstrating the potential of repurposed PA6 fishing lines as a viable alternative to commercial PA6 powder. This novel PA6 fishing line adsorptive membrane demonstrates excellent potential for efficient gold recovery while addressing environmental concerns by repurposing nylon waste and contributing to the reduction of microplastic pollution, offering a sustainable solution for resource recovery and waste management.