Investigation of Isotherm, Kinetics and Thermodynamics of Ciprofloxacin Adsorption by Molecularly Imprinted Polymer from Aqueous Solutions

Background: Improper use of antibiotics and their discharge into the environment have serious and dangerous consequences. About 30-30% of antibiotics are not metabolized in the body and enter the environment through urine and feces, so the main source of antibiotics in the environment is wastewater treatment plant effluent. The aim of this study was to investigate the removal efficiency of ciprofloxacin (CIP) from aqueous media by molecularly imprinted polymer (MIP). Methods: This study is an experimental-laboratory study performed in a reactor with a discontinuous system. In this study, the effect of parameters such as solution pH, adsorbent dose, initial concentration of CIP, reaction contact time and reaction temperature on the reduction rate the antibiotics amoxicillin and CIP were administered. Results: Results showed that removal efficiency for both antibiotics was increased with increasing contact time and adsorbent mass and initial antibiotics concentration while decreased with increasing solution pH and the best pH to remove was neutral pH. Equilibrium data were analyzed by Freundlich and Langmuir isotherm models and the results showed that the data from Langmuir isotherm had a higher correlation coefficient. In addition, the reaction rate was performed with pseudo-first-order and pseudo-second-order models, and the data were consistent with pseudo second order kinetic kinetics. According to result of thermodynamic study, entropy changes (ΔSO), enthalpy changes (ΔHO) and Gibbs free energy (ΔGO) were negative that represent the adsorption process is spontaneous and exothermic. Conclusion: The results of this study showed that the process of adsorption of MIP is a very effective process for removing the CIP from aqueous solutions.