Ciprofloxacin desorption from gel type ion exchange resin: Desorption modeling in batch system and fixed bed column
Abstract
The aim of this paper was to assess the desorption of ciprofloxacin (CIP) from the Supergel™ SGC650H resin and to evaluate the possibility of future reuse of the adsorbent by applying adsorption cycles. Preliminary desorption tests by using different aqueous HCl concentrations as eluent agents and adsorption experiments with the previously treated resin with these same solutions were carried out in batch system to determine the best eluent condition. Physico-chemical characterization tests were performed for virgin and HCl-treated resin, evidencing changes on the resin’s structure and functional groups caused by the eluents. The preliminary results showed that the HCl concentration of 2 mol L−1 provided both the CIP-desorption efficiency from the resin and the improvement of CIP adsorption capacity. Therefore, this eluent concentration was applied for the further equilibrium experiments in batch system. Mathematical modeling was applied to the kinetic and equilibrium desorption data obtained in batch system, evidencing that internal diffusion model showed a good agreement with the experimental data. Based on the estimated parameters from the independent batch experiments, the model was able to adequately predict the desorption kinetic behavior in fixed bed column. Overall, the results showed that the HCl aqueous solution of 2 mol L−1 could be efficiently applied to assess adsorption cycles, due to the high desorption efficiency combined with the enhancement of the resin’s capacity. Furthermore, the present work provided a robust and predictive mathematical model, which could support the design and the scale up of industrial level equipment.