High Performance of Ciprofloxacin Removal Using Heterostructure Material Based on the Combination of CeO2 and Palygorskite Fibrous Clay

Abstract

Ciprofloxacin, a second-generation fluoroquinolone, is widely used in human and veterinary medicine. However, it is known for its environmental persistence and ability to promote bacterial resistance, causing genotoxic impacts and chronic toxicity in various aquatic life forms. Adsorption is an effective technique for water treatment, removing multiple organic molecules, even in minimal concentrations. Hybrid materials based on fibrous clay minerals, such as palygorskite, are promising for environmental remediation, significantly when modified with oxides to improve their adsorption properties. This work prepared and characterized a CeO2/palygorskite hybrid material using various physicochemical techniques (XRD, FTIR, BET, SEM), which indicated the formation of the heterostructure material with interesting textural properties. This CeO2/palygorskite was evaluated as an adsorbent of the antibiotic drug ciprofloxacin. The influence of pH (3, 7, and 9) and ciprofloxacin concentration (6, 8, 10, and 14 ppm) on adsorption were studied, using pseudo-first- and pseudo-second-order kinetic models. The pseudo-second-order model showed the best fit (R2 > 0.99) and the lowest squared error (SSE), indicating chemisorption. The Langmuir, Freundlich, and Temkin isotherms were applied to the experimental data, where the Langmuir model had the best fit, indicating monolayer adsorption with a maximum capacity of 15 mg·g−1. Post-adsorption characterization by FTIR confirmed the structural stability of the material, highlighting its promising application in environmental remediation due to its high concentration of adsorbents.