Recovery of copper oxide nanostructures from waste printed circuit boards for environmental remediation: synthesis, characterization, and photocatalytic application investigation

Electronic waste (e-waste) has emerged as a major environmental issue globally, driven by rapid technological advancements and short product lifespans. Waste printed circuit boards (WPCBs), regarded as a secondary resource of metal supplies, contain valuable metals, including copper, which can be recycled and reused to support sustainable material sourcing. This study introduces a precursor-free and application-oriented environment-friendly approach for recovering copper from WPCBs in the form of copper oxide nanostructured powders. Unlike conventional CuO recovery methods that depend on external copper salts or complex, energy-intensive synthesis routes, the proposed process directly utilizes the metallic fraction of WPCBs as the sole copper source. Copper clads from discarded motherboards were leached in dilute nitric acid, followed by precipitation and calcination, to yield CuO nanoparticles (NPs) of varied morphologies. Structural and morphological analysis (XRD, FTIR, UV-DRS, SEM–EDX, TEM, XPS, and BET) confirmed the formation of CuO. The recovered CuO NPs were directly applied as visible-light photocatalysts for Congo red (CR) dye degradation, achieving 96.79% removal within 180 min, outperforming several reported CuO-based systems. By combining a simplified, precursor-free recovery process with a practical environmental application, this study not only reduces the ecological footprint of e-waste management but also demonstrates the dual benefit of converting e-waste into efficient nanomaterials for wastewater remediation, advancing the principles of the circular economy.