Recovery of copper/carbon matrix nanoheteroarchitectures from recyclable electronic waste and their efficacy as antibacterial agents

Abstract

Innovative solutions are urgently needed with the growing environmental hazard of electronic waste (e-waste) and the rising global threat of bacterial infections. This study addresses both issues by using e-waste to produce copper nanoparticles within a carbon matrix (Cu/C NPs), mitigating environmental hazards while exploring their antibacterial properties. Printed circuit boards from discarded computers were collected and treated with 2 M ammonium citrate dissolved in 8% ammonia solution. The leached solution was used to synthesize copper particles using ascorbic acid. The synthesized Cu/C NPs were characterized using various techniques such as EDX, field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. The antibacterial activity of Cu/C NPs against <i>Escherichia coli</i> (<i>E. coli</i>) and <i>Staphylococcus aureus</i> (<i>S. aureus</i>) was evaluated using colony-forming unit (CFU) reduction assay and calculating the minimum inhibitory concentrations (MICs). The Cu/C NPs were found to be effective against <i>E. coli</i> and <i>S. aureus</i> with 100% and 98% CFU reduction, respectively, with MICs ranging from 250 to 375 μg mL^-1 for <i>E. coli</i> and 375 to 750 μg mL^-1 for <i>S. aureus</i>, according to the bacterial load. The bactericidal kinetics showed complete bacterial elimination after 5 and 7 hours for <i>E. coli</i> and <i>S. aureus</i>, respectively. This study presents a sustainable approach for utilizing e-waste and demonstrates the potential of the recovered nanoparticles for antibacterial applications.