Superabsorbent hydrogel based on angico gum containing a hybrid mineral–carbon fraction for environmental remediation: Potential for ciprofloxacin removal

The increasing presence of emerging contaminants in aquatic environments has motivated the development of adsorbent materials derived from natural matrices. In this study, a superabsorbent hydrogel based on angico gum (HGA) was synthesized and modified by incorporating a hybrid mineral–carbon fraction composed of montmorillonite, sepiolite, and activated carbon (MIN) to remove ciprofloxacin (CPX) from aqueous solutions. The composite (HGA-MIN) was characterized using FTIR, XRD, TG, SEM, micro-CT, swelling analysis, pH _pzc determination, and reusability tests. FTIR confirmed the functional groups of the polymeric network, while XRD indicated a predominantly amorphous structure with characteristic peaks of the incorporated clays. TG analysis showed an increased residue in HGA-MIN, confirming the presence of MIN in the matrix. SEM revealed a porous morphology for HGA and greater surface roughness in HGA-MIN. Micro-CT demonstrated a reduction in porosity from 81.32% (HGA) to 22.99% (HGA-MIN). The composite maintained a high swelling capacity (14.81%), and its pH _pzc (8.52) favored CPX adsorption under acidic conditions. Adsorption tests showed a maximum capacity of 234.8 mg g ^-1 , with the Langmuir and Sips models providing the best fit. Kinetic studies followed the pseudo-second-order model, reaching equilibrium in 30 min. Reusability assays indicated that HGA-MIN retained over 90% of its adsorption capacity after five cycles. These findings highlight HGA-MIN as an efficient material for the removal of pharmaceutical contaminants from water.