Synthesis of a novel HoFeO3/Ho3Fe5O12 nanoadsorbent for efficient absorption of ciprofloxacin from liquid-phase: Modeling and optimization using response surface methodology

Abstract

In this research, a new magnetic nano adsorbent was prepared for the absorption of the ciprofloxacin antibiotic from aqueous media. Also, some parameters affecting the absorption such as time, pH, the concentration of ciprofloxacin, and the nano adsorbent dose, were investigated. A response surface methodology (RSM) based on a central composite design (CCD) was used to determine the optimum points in the ciprofloxacin adsorption and create a valid mathematical model to predict the absorption of ciprofloxacin by the new nano adsorbent. The structure and morphological properties of the synthesized adsorbent were characterized by some special analysis. After determining the optimal points, the kinetics, isotherm and the recovery rate of the adsorbent were also investigated. The results showed that the quadratic model described the best adsorption of ciprofloxacin onto nano adsorbent, and the R2, adjusted R2, and predicted R2 were 0.9867, 0.9808, and 0.9622, respectively. Under optimized conditions (time 45 min, adsorbent dosage 700 mg/L, pH 5, initial ciprofloxacin concentration 25 mg/L), the removal efficiency with a desirability factor of 1 was 91.50 %, and the predicted one was 90.49%. Also, the process follows the quadratic model and the Langmuir isotherm. The recovery results determined that the absorption rate after 5 consecutive cycles is still close to 80%. Therefore, it can be concluded that the new nano adsorbent can be an efficient adsorbent in removing ciprofloxacin from aquatic environments.