Efficient removal of moxifloxacin from aqueous solutions using sulfonated graphene oxide: Adsorption mechanisms, thermodynamics, and reusability

• Published in: Journal of water process engineering Vol. 67; p. 106187
• Main Authors: Shaha, Chironjit Kumar, Saha, Sudipta, Karmaker, Subarna, Saha, Tapan Kumar
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2024
• Subjects: Adsorption; Kinetics; Moxifloxacin; Sulfonated graphene oxide; Thermodynamics; Thermodynamics; Moxifloxacin; Kinetics; Adsorption; Sulfonated graphene oxide
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2024.106187

Removing pharmaceutical pollutants from aquatic environments is a significant focus in current environmental research. Graphene-based materials, valued for their stability, are considered effective adsorbents for removing pharmaceuticals from contaminated water. This study explored the adsorptive removal of moxifloxacin onto sulfonated graphene oxide (SGO) from aqueous solutions under various conditions, such as contact time, pH, adsorbent amount, moxifloxacin concentration, presence of inorganic ions, and temperature. The equilibrium adsorption of moxifloxacin onto SGO was examined at different temperatures. The adsorption was confirmed using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The maximum adsorption occurred within 240 min at pH 4 with an adsorbent dosage of 0.01 g/50 mL of a 50 μmol/L moxifloxacin solution. The kinetic data best fit the pseudo-second-order model, rather than the pseudo-first-order or Elovich models. The Langmuir isotherm model described the equilibrium adsorption isotherms, with a maximum adsorption capacity of 1000.00 μmol/g at 25 °C. The values of activation energy (Ea) and thermodynamic parameters (ΔG⧧, ΔH⧧, ΔS⧧, ΔG, ΔH, and ΔS) indicated that the adsorption of moxifloxacin onto SGO is a spontaneous, endothermic physisorption process. A high release of moxifloxacin (99 %) from antibiotic-loaded SGO occurred in 1 mol/L HCl in DMF within 240 min. Even after five adsorption/desorption cycles, SGO maintained over 90 % of its initial adsorption capacity. Therefore, SGO could serve as an effective adsorbent for removing the antibiotic moxifloxacin from aquatic environments. [Display omitted] •SGO effectively eliminates moxifloxacin from aqueous solutions, as confirmed by SEM and EDX spectroscopy.•The adsorption of moxifloxacin on SGO in aqueous solution follows pseudo-second-order kinetic and Langmuir isotherm models.•Thermodynamic study verifies that the adsorption is spontaneous and endothermic physisorption process.•SGO retains over 90% of its initial adsorption capacity even after five adsorption/desorption cycles.•SGO is a promising adsorbent for removing moxifloxacin from aquatic environments.