Synergistic Photocatalytic Performance and Reusability of CuO@CeO₂ Nanocomposites for Degradation of Tetracycline Wastewater

¹ Department of Chemical Engineering, Faculty of Engineering, Diponegoro University, Jl. Prof. Soedarto, SH, Tembalang, 50275 Semarang Indonesia
² Advanced Membrane Technology Research Centre (AMTEC), Universiti Teknologi Malaysia, Skudai, Johor, Malaysia
³ Research Center for Chemistry, National Research and Innovation Agency, Serpong, South Tangerang, 15134, Indonesia

^* Corresponding author: tdkusworo@che.undip.ac.id

Abstract

The environmental persistence of tetracycline in aqueous systems represents a critical concern due to its recalcitrant nature and potential to exacerbate antimicrobial resistance. In response to this challenge, a novel CuO@CeO₂ nanocomposite was synthesized via a combination of hydrothermal and co-precipitation techniques. The optimized composite, with a CuO:CeO₂ molar ratio of 1:1:1, achieved a maximum degradation efficiency of 72.00% for a 200 mg/L tetracycline solution. Enhanced photocatalytic activity was attributed to the formation of a p–n heterojunction, which facilitated improved charge carrier separation and reduced the band gap energy to 2.86 eV. Kinetic analysis revealed that the Bangham (R² = 0.9912) and intraparticle diffusion (R² = 0.9810) models best described the degradation process, suggesting a coupled mechanism of surface adsorption and internal pore diffusion. Equilibrium data were most accurately represented by the Dubinin–Radushkevich isotherm (R² = 0.9619). Reusability assessments demonstrated that the nanocomposite retained over 85% of its initial performance across three consecutive cycles, confirming its structural integrity and operational stability. These findings highlight the potential of CuO@CeO₂ as a robust and multifunctional material for advanced antibiotic remediation, with promising applicability in integrated membrane-photocatalytic systems for industrial-scale wastewater treatment.