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Research Article

Solar-Enhanced Photocatalytic Degradation of Pharmaceutical Residues in Wastewater Using Fe-, Cu-, and Zn- Doped TiO₂ Nanomaterials

Authors

  • Okpoji, Awajiiroijana U. Department of Pure and Industrial Chemistry, University of Port Harcourt, Choba, Nigeria https://orcid.org/0009-0003-9994-7594

    ao.okpoji@stu.unizik.edu.ng

  • Ekwere, Ifiok O. Department of Chemistry, Akwa Ibom State University, Ikot Akpaden, Nigeria
  • Igwegbe, Kelvin C. Forensic Toxicology Laboratory, National Counter Terrorism Centre, Abuja, Nigeria
  • Etesin, Usoro M. Department of Chemistry, Akwa Ibom State University, Ikot Akpaden, Nigeria
  • Ugwuanyi, Gerald C. Department of Pure and Industrial Chemistry, University of Port Harcourt, Choba, Nigeria
  • Okpanachi, Clifford B. Department of Pure and Industrial Chemistry, Prince Abubakar Audu University, Anyigba, Nigeria
  • Ewuola, Akinola A. Department of Chemistry, Federal University of Technology, Akuru, Nigeria
  • Mojisola, Kareem M. Departemnt of Science Education, College of Education and Allied Studies, Bayero University, Kano, Nigeria
  • Ezekwueme, Obianuju I. Department of Chemistry, Michael Okpara University of Agriculture, Umudike, Nigeria

Abstract

Pharmaceutical residues are increasingly recognised as critical emerging contaminants due to their persistence, bioactivity, and incomplete removal in conventional wastewater treatment systems. In this study, TiO₂ nanomaterials doped with Fe, Cu, and Zn were synthesised via a sol–gel route and comprehensively characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and UV–Vis diffuse reflectance spectroscopy (DRS). Their photocatalytic performance was evaluated under solar-simulated irradiation for the degradation of diclofenac, paracetamol, and sulfamethoxazole. High-performance liquid chromatography (HPLC) and total organic carbon (TOC) analysis were employed to quantify pollutant degradation and mineralisation, respectively. Metal doping reduced crystallite size, enhanced surface area, and narrowed the TiO₂ bandgap, thereby extending visible-light absorption. Among the catalysts, Fe–TiO₂ at 5% doping exhibited the highest activity, achieving >90% degradation of all three pharmaceuticals and >70% TOC removal within 120 minutes. Kinetic analysis confirmed pseudo-first-order behaviour (R² > 0.95), with Fe–TiO₂ showing the fastest rate constants (0.024–0.030 min⁻¹). Scavenger experiments identified hydroxyl (•OH) and superoxide (O₂•⁻) radicals as the primary reactive species. These findings highlight the promise of solar-assisted photocatalysis with metal-doped TiO₂ as a sustainable and efficient strategy for removing pharmaceutical residues from wastewater, with strong potential for practical application in regions with abundant solar resources.

Keywords:

Metal Doping Photocatalysis TiO₂ Nanomaterials Wastewater Treatment

Article information

Journal

Journal of Environment, Climate, and Ecology

Volume (Issue)

2(2), (2025)

Pages

56-62

Published

12-09-2025

How to Cite

Okpoji, A. U., Ekwere, I. O., Igwegbe, K. C., Etesin, U. M., Ugwuanyi, G. C., Okpanachi, C. B., Ewuola, A. A., Mojisola, K. M., & Ezekwueme, O. I. (2025). Solar-Enhanced Photocatalytic Degradation of Pharmaceutical Residues in Wastewater Using Fe-, Cu-, and Zn- Doped TiO₂ Nanomaterials. Journal of Environment, Climate, and Ecology, 2(2), 56-62. https://doi.org/10.69739/jece.v2i2.961

References

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