Adsorption of Ciprofloxacin from Aqueous Environment by Using Synthesized Nanoceria

Antibiotics are widely detected emerging contaminants in water environments and possess high potential risks to human health and aquatic life. However, conventional water treatment processes cannot remove them sufficiently. To develop innovative nanoadsorbents for effectively remove antibiotic contaminants from water environment, nanoceria were prepared via in situ precipitation method, and evaluated their adsorption capacity for a model antibiotic, ciprofloxacin (CIP). The properties of the prepared nanoceria were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and vibration sample magnetization (VSM). The effect of various operating parameters such as pH, initial CIP concentration, contact time, and adsorbent dosage on adsorptions of CIP were studied in batch experiments. Maximum adsorption capacity of the nanoceria was 49.38 mg/g at the conditions of pH 5, initial CIP concentration of 200 mg/dm³ and adsorbent dosage of 0.2 g/dm³, when 95.43 % of the CIP was removed. For adsorption kinetics, both pseudo-first-order and pseudo-second-order models can well describe the experimental data, indicating that the adsorption process was controlled by both physical diffusion and chemical interaction. For adsorption isotherms, the Freundlich model could fit the experimental data better than the Langmuir and Temkin models, suggesting a multilayer adsorption process. The thermal dynamics study showed the absorption process was spontaneity, exothermic, and irreversible. Finally it was concluded that the nanoceria can be used effectively for CIP removal.