N-doped TiO2/prosopis juliflora biochar nanocomposites for removal of ciprofloxacin from pharmaceutical industrial wastewater

The contamination of aquatic ecosystems by pharmaceutical residues, particularly ciprofloxacin (CIX), can pose severe environmental and public health risks. This study aimed to optimize the photodegradation of CIX from pharmaceutical industrial wastewater using N-doped TiO₂/Biochar Nanocomposites. A novel N-doped TiO₂/BC nanocomposite was synthesized via sol-gel techniques and evaluated under UV and sunlight irradiation. Kinetic degradation parameters were optimized using Response Surface Methodology (RSM) with a Central Composite Design (CCD). The optimized conditions included a contact time of 72 min, a pH of 6.9, a nanocomposite dosage of 2 g/L, and an initial CIX concentration of 50 mg/L. Maximum degradation efficiencies of 98.9% and 96.9% were achieved under UV and visible light, respectively. The statistical evaluation confirmed the model's validity and adequacy, with a high F-value (86,345) and significant model terms (p < 0.0001). Additionally, the lack-of-fit test yielded a non-significant value (p = 0.93), indicating an excellent fit of the model to the data. The determination coefficients (R² 0.98, adjusted R² = 0.93, and predicted R² = 0.96) further supported the model's robustness and predictive accuracy. The optimized parameters were applied to real pharmaceutical wastewater, achieving degradation efficiencies of 86.9% and 84.3% for UV and sunlight, respectively. These findings highlight the potential of N-doped TiO₂/BC nanocomposites for efficient CIX degradation and pharmaceutical pollutant removal by modifying the limitations of pristine TiO₂. Further, it solves scaling up the process and optimizes photocatalyst selection, stability, and reusability for practical environmental applications.