Abstract The increasing presence of emerging contaminants in aquatic environments has motivated the development of adsorbent materials derived from natural matrices. In this study, for the first time, a superabsorbent hydrogel based on angico gum (HGA) was synthesized and modified by incorporating a hybrid mineral-carbon fraction (MIN), composed of montmorillonite, sepiolite, and activated carbon, aiming to combine the high adsorption capacity of mineral adsorbents with the structural and reusability advantages of hydrogels for the removal of ciprofloxacin (CPX) from aqueous solutions. The resulting composite (HGA-MIN) was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TG), scanning electron microscopy (SEM), and X-ray microcomputed tomography (micro-CT). FTIR and XRD analyses confirmed the preservation of the polymeric structure and the successful incorporation of the mineral fraction into the matrix. Micro-CT analysis revealed a reduction in porosity from 81.32% (HGA) to 22.99% (HGA-MIN). The composite exhibited a high swelling capacity (14,811.83%) and a point of zero charge (pH pzc ) of 8.52, favoring CPX adsorption under acidic conditions. Adsorption experiments showed a maximum adsorption capacity of 234.8 mg g − 1 , with equilibrium reached within 30 min. Kinetic data followed the pseudo-second-order model, while equilibrium data were best described by the Sips isotherm. Thermodynamic analysis indicated that the adsorption process is spontaneous and exothermic, and reusability tests demonstrated retention of more than 90% of the adsorption capacity after five cycles. These results highlight HGA-MIN as an efficient and sustainable material for the removal of ciprofloxacin from water.
Silva et al. (Sun,) studied this question.