Development of Variable Charge Cationic Hydrogel Particles with Potential Application in the Removal of Amoxicillin and Sulfamethoxazole from Water

Cationic hydrogel particles (CHPs) crosslinked with glutaraldehyde were synthesized and characterized to evaluate their removal capacity for two globally consumed antibiotics: amoxicillin and sulfamethoxazole. The obtained material was characterized by FTIR, SEM, and TGA, confirming effective crosslinking. The optimal working pH was determined to be 6.0 for amoxicillin and 4.0 for sulfamethoxazole. Under these conditions, the CHPs achieved over 90.0% removal of amoxicillin after 360 min at room temperature, while sulfamethoxazole removal reached approximately 60.0% after 300 min. Thermodynamic analysis indicated that adsorption occurs through a physisorption process and is endothermic. The ΔH° values of 28.38 kJ mol^-1, 12.39 kJ mol^-1, and ΔS° 97.19 J mol^-1 K^-1, and 33.94 J mol^-1 K^-1 for AMX and SMX, respectively. These results highlight the potential of CHPs as promising materials for the removal of such contaminants from aqueous media.