Development of copper oxide-based photocatalysts from copper waste for visible light-driven Congo red degradation

The environmentally friendly disposal of copper waste from automobile shops is crucial for preventing potential environmental hazards. This study introduces an innovative approach to repurpose retrieved copper by converting it into a nanomaterial, specifically a copper oxide-based nanoparticles (CSCNC). Using extracts derived from Curcuma amada leaves and Strychnos potatorum seeds, a green synthesis process were employed to synthesize CSCNCs. The synthesis involved dissolving the reduced copper waste, leaching copper into the solution, and precipitating nanoparticles using a pH-controlled method. The synthesized CSCNCs possess a monoclinic crystalline structure with a morphology resembling nano-leaf sheets, exhibiting an average pore diameter of 14 nm and a mesoporous structure. These CSCNCs demonstrated efficient degradation of Congo red (CR), a representative dye, under visible light irradiation, with a degradation efficiency of 91% under optimized conditions. Kinetic analysis revealed that pseudo-second-order reactions provided a better fit for the degradation process, with CSCNCs exhibiting exceptional performance. Radical trapping experiments identified hydroxyl radicals and holes as the primary species involved in the photocatalytic degradation mechanism. The development of CSCNCs represents a significant advancement in the repurposing of copper waste, contributing to environmental sustainability and protection while offering insights into potential applications in wastewater treatment.