Efficient removal of ofloxacin antibiotic from aqueous solution via CuCo-modified Al-MCM-41: an experimental and theoretical study

Abstract

We explore herein the efficient removal of ofloxacin (OFL), a prevalent fluoroquinolone antibiotic, from aqueous solutions utilizing CuCo-modified Al-MCM-41 as an innovative adsorbent. Through a combination of experimental and theoretical methodologies, the adsorbents were characterized, and their performance in OFL adsorption was analyzed. Characterization techniques, including XRD, N₂ adsorption–desorption, FTIR, SEM, and EDS, confirmed the successful incorporation of copper and cobalt into the mesoporous structure of Al-MCM-41, enhancing the material's adsorption capacity compared to monometallic systems. Adsorption studies revealed that the optimal Cu : Co ratio (7 : 3) achieved 90.77% removal efficiency at neutral pH. Kinetic modeling identified a two-stage process best described by a pseudo-second-order (PSO) model, while equilibrium data conformed to the Langmuir, Freundlich, and Temkin isotherm. Density functional theory (DFT) studies provided insights into the adsorption mechanism, revealing synergistic effects of Cu and Co on OFL interaction and electronic property modulation of the adsorbent. A removal efficiency of 588 mg g⁻¹ for OFL demonstrated the strong feasibility of this adsorbent for wastewater treatments. This cost-effective, scalable adsorbent offers a sustainable solution for wastewater treatment, reducing antibiotic pollution, combating resistance, and supporting cleaner water resources—key goals in sustainable resource management.