Introduction: In this study, a synthesis strategy was employed to enhance the photocatalytic performance of graphitic carbon nitride (g-C3N4) for the degradation of the antibiotic ciprofloxacin (CIP) as an environmental pollutant.

Materials and Methods: Graphitic carbon nitride (g-C₃N₄) samples were synthesized using melamine and urea precursors at a weight ratio of 80:20 through calcination at 550 °C for 3 h, with a heating rate of 5 °C/min, under CO₂ and N₂ atmospheres at a gas flow rate of 20 mL/min. To investigate the effects of precursor composition and calcination atmosphere, reference samples were also prepared using pure melamine under similar conditions. The structural, morphological, surface, and optical properties of the synthesized samples were characterized using XRD, FTIR, FE-SEM, BET, UV–Vis DRS, and PL analyses.

Results and Discussions: The photocatalytic activity of the synthesized samples was evaluated for ciprofloxacin degradation under visible-light irradiation. Results showed that under optimized conditions (catalyst dosage = 0.8 g/L; ciprofloxacin concentration = 20 mg/L; pH = 5; irradiation time = 120 min), the MUC sample exhibited the highest efficiency, removing more than 98% of ciprofloxacin within 120 minutes. Kinetic analysis indicated that the degradation followed pseudo-first-order kinetics, with the reaction rate decreasing at higher initial pollutant concentrations. Reusability and stability tests further confirmed that the catalyst retained its high activity and structural integrity after multiple cycles.

Conclusions: These findings demonstrate that tuning the synthesis conditions and precursor composition is an effective approach to enhance the photocatalytic performance of g-C3N4 for the removal of persistent pharmaceutical contaminants.