Assessing TiO ₂ /Chitosan‐Based Hydrogels for Water Remediation: Sunlight‐Driven Degradation of Antibiotics in Water

ABSTRACT The widespread occurrence of pharmaceutical contaminants in aquatic environments requires the development of sustainable and efficient water treatment technologies capable of operating under realistic conditions. In this study, an integrated remediation system based on chitosan hydrogels embedding TiO ₂ nanoparticles is investigated, combining pollutant adsorption and photocatalytic degradation within a single, reusable system. The performance of the composite hydrogels was evaluated for the removal of sulfamethoxazole (SMX), selected as a model antibiotic, under simulated and real solar irradiation, using mineral water to reproduce environmentally relevant ionic strength conditions. Structural characterization confirms the effective immobilization of TiO ₂ within the hydrogel matrix, ensuring material stability and preventing nanoparticle release into water. The hybrid system exhibits high SMX removal efficiency (>85% for 10 ⁻⁵ m SMX solutions) due to the synergistic interplay between adsorption and sunlight‐driven photocatalysis, with TiO ₂ showing photocatalytic activity under solar irradiation. Moreover, the hydrogels show excellent structural integrity, resistance to microbial colonization and biofouling, and stable performance over multiple adsorption–photocatalysis cycles. These results demonstrate the robustness and practical applicability of TiO ₂ /chitosan‐based hydrogels for solar‐driven water remediation and provide a promising platform for the development of advanced multifunctional materials for the treatment of emerging contaminants.