Adsorption of Pharmaceutical Compounds from Water on Chitosan/Glutaraldehyde Hydrogels: Theoretical and Experimental Analysis

Abstract

Chitosan-based hydrogels are used in the adsorption of pharmaceutical compounds from water. The adsorption process of diclofenac and naproxen on chitosan hydrogels cross-linked with glutaraldehyde has been studied theoretically and experimentally. According to the thermodynamic properties, the adsorption processes were spontaneous and endothermic, due to the negative values of Gibbs free energy, and the enthalpies of formation were positive. Furthermore, the different systems were studied by electrostatic potential maps, where the functional groups (amino and hydroxyl) represented the active sites of the hydrogel. The maximum adsorption capacity obtained for diclofenac and naproxen was 108.85 and 97.22 mg/g, respectively, at a temperature of 308.15 K. On the other hand, the adsorbent was characterized by FTIR (Fourier Transform Infrared Spectroscopy) and XRD (X-ray Diffraction) before and after the adsorption of the drugs to confirm the binding of the adsorbates on the surface of the material.