Advanced photocatalytic degradation of Ibuprofen using CuO-Polypyrrole/activated carbon hydrogel for sustainable water purification: characterization and application.

Abstract

The contamination of aquatic environments by pharmaceutical residues, particularly ibuprofen (IBU), necessitates effective removal strategies. This study presents the synthesis and characterization of CuO-polypyrrole/activated carbon hydrogel (Cu@Ppy/AC) as a photocatalyst for IBU degradation under visible light. Characterization techniques including XRD, FTIR, SEM, and BET confirmed the structural and physicochemical properties of Cu@Ppy/AC. Photocatalytic performance was optimized by investigating pH, catalyst dosage, IBU concentration, and reaction time. Under optimal conditions (0.5 g/L catalyst, pH 6, 5 mg/L IBU), complete degradation occurred within 40 min, followed by total mineralization within 80 min. The reaction followed first-order kinetics (k = 0.0365 min⁻¹), with hydroxyl radicals (OH•) and superoxide radicals (O₂•⁻) identified as key oxidative species. The oxidation pathway proceeded through a sequence of reactions including hydroxylation, decarboxylation, and cleavage of the aromatic ring structure, ultimately resulting in the full mineralization of ibuprofen into carbon dioxide (CO₂) and water (H₂O). The synergistic interaction between CuO, polyaniline hydrogel, and activated carbon enhanced charge separation efficiency, improving catalytic activity under visible light irradiation. Toxicological assessments using HEK293T and HepG2 cell lines revealed that partially oxidized IBU intermediates exhibited transient cytotoxicity, which diminished upon complete mineralization. Cu@Ppy/AC retained over 85% efficiency after 7 cycles, demonstrating high stability and recyclability. Comparative analysis highlighted its superior degradation efficiency and material sustainability over other reported photocatalysts. These findings establish Cu@Ppy/AC as a cost-effective and sustainable photocatalyst for pharmaceutical wastewater treatment, with potential for large-scale application and remediation of multiple pharmaceutical contaminants.