Green synthesized Cu-doped CeO2 nanoparticles for Congo red dye adsorption and antibacterial action

Abstract

Abstract The removal of pollutants from water bodies is crucial for the well-being of humanity and is a topic of global research. Researchers have turned their attention to green synthesized nanoparticles for wastewater treatment due to their eco-friendly nature, biocompatibility, and cost-effectiveness. This work demonstrates the efficient removal of organic dye and both gram-positive and gram-negative bacteria from water bodies using copper-doped cerium oxide nanoparticles synthesized with Murraya Koenigii extract. Characterized via various methods, the 15% copper doped cerium oxide nanoparticles (Cu 15% NPs) exhibited maximum Congo red dye adsorption (98% degradation in 35 min). Kinetic analysis favoured a pseudo-second-order model, indicating the chemical nature of adsorption. Equilibrium adsorption isotherms aligned with the Langmuir model, indicating homogenous monolayer dye adsorption on the doped adsorbent. The maximum uptake of adsorbate, Q m obtained from Langmuir model for Cu 15% NPs was 193 mg g−1. The study also showed enhanced antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa for Cu-doped ceria, attributed to generation of reactive oxygen species (ROS) induced by the redox cycling between Ce3+ and Ce4+. This substantiated that the green synthesized copper doped cerium oxide nanoparticles are potential candidates for adsorptive removal of Congo red dye and as antibacterial agents.