DOI: https://doi.org/10.9767/bcrec.20651

Visible-Light Photocatalytic Degradation of Metronidazole Using Bismuth Oxide-Doped Erbium Oxide Anchored Graphene Oxide Nanocomposites: Kinetics and Mechanism

1Chemical Engineering Department, College of Engineering, Al-Nahrain University, Baghdad, Iraq

2Department of Engineering and Computer Science, McNeese State University, Lake Charles, LA, United States

3Chemical Engineering Department, Faculty of Engineering, Alexandria University, Alexandria, Egypt

Received: 25 Jan 2026; Revised: 29 Mar 2026; Accepted: 30 Mar 2026; Available online: 1 Apr 2026; Published: 30 Oct 2026.
Editor(s): Istadi Istadi
Open Access Copyright (c) 2026 by Authors, Published by BCREC Publishing Group
Creative Commons License This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Fulltext View|Download

Citation Format:
Cover Image
Abstract

Metronidazole (MNZ) is a persistent pharmaceutical contaminant that resists conventional wastewater treatment. In this work, a visible-light-active Bi2O3–Er2O3/graphene oxide (GO) nanocomposite was synthesized by a co-precipitation method.  This nanocomposite was evaluated for the photocatalytic degradation of MNZ in aqueous solution. Structural and optical characterization (XRD, FTIR, SEM, TEM, BET, PL, and UV–Vis DRS) confirmed the successful anchoring of Bi2O3–Er2O3 nanoparticles onto GO sheets. That resulted in improved visible-light absorption and blocked charge-carrier recombination. The composite containing 20 wt% GO showed the highest photocatalytic activity. It achieved near-complete MNZ removal under exposure to visible light. The improved performance was attributed to the combined effects of many factors. Those include Bi2O3–Er2O3-induced visible-light response, Er2O3-assisted charge trapping, and efficient electron transport through GO. The study included examining the effects of many factors. Those included the solution pH, catalyst dosage, initial MNZ concentration, and GO content. Optimal degradation was found in alkaline conditions. The catalyst was found to be stable and reusable. Therefore, it has high potential for sustainable antibiotic removal from wastewater. Copyright © 2026 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

 
Keywords: Wastewater Treatment; Adsorption; Graphene Oxide; Metronidazole; Material Characterization

Article Metrics:

Article Info
Section: Original Research Articles
Language : EN
Recent articles
Visible-Light Photocatalytic Degradation of Metronidazole Using Bismuth Oxide-Doped Erbium Oxide Anchored Graphene Oxide Nanocomposites: Kinetics and Mechanism Facile Fabrication of Alginate–BiBDC Composite Beads for Efficient Removal of Methylene Blue from Aqueous Solutions Improvements in Photocatalytic Activity in Visible Light Destruction of Chlorpyrifos in a Batch Reactor Applying the Z-Scheme g-C3N4/Fe3O4/CuWO4/CuO Heterojunction, Including Fabrication, Characterization, and Recycling Optimized Cobalt-Loaded Palm Oil Fuel Ash (Co/POFA) Catalyst for Syngas Production via Ethanol Dry Reforming Sustainable Removal of Methylene Blue Using an Inverse-Vulcanized Polysulfide Derived from Waste Cooking Palm Oil Influence of Ni/CeO2 on Pyrolytic Conversion of FOBS to Hydrogen Formation More recent articles
  1. Tiwari, B., Sellamuthu, B., Ouarda, Y., Drogui, P., Tyagi, R.D., Buelna, G. (2017) Review on fate and mechanism of removal of pharmaceutical pollutants from wastewater using biological approach, Bioresource Technology, 224, 1-12, DOI: 10.1016/j.biortech.2016.11.042
  2. Edwards, D.I. (1980) Mechanisms of selective toxicity of metronidazole and other nitroimidazole drugs, Sexually Transmitted Infections, 56 (5), 285-290, DOI: 10.1136/sti.56.5.285
  3. Boumahdi, N., Hadj-Ziane-Zafour, A., Yaiche-Achour, H., Khalaf, H. (2022) Preparation of Bi2O3/TiO2–Montmorillonite Nanocomposites and Their Applications to the Photodegradation of Pentachlorophenol, Bulletin of Chemical Reaction Engineering & Catalysis, 17 (1), 78-87, DOI: 10.9767/bcrec.17.1.12421.78-87
  4. Zeitoun, Z., El-Shazly, A.H., Nosier, S., Elmarghany, M.R., Salem, M.S., Taha, M.M. (2020) Performance Evaluation and Kinetic Analysis of Photocatalytic Membrane Reactor in Wastewater Treatment, Membranes, 10(10), 276, DOI: 10.3390/membranes10100276
  5. Zeitoun, Z., Selem, N.Y. (2023) A comprehensive review on textile wastewater treatment by coupling TiO2 with PVDF membrane, Bulletin of the National Research Centre, 47(1), 153, DOI: 10.1186/s42269-023-01131-9
  6. Bhatia, A., Hautier, G., Nilgianskul, T., Miglio, A., Sun, J., Kim, H.J., Kim, K.H., Chen, S., Rignanese, G.-M., Gonze, X., Suntivich, J. (2016) High-mobility bismuth-based transparent p-type oxide from high-throughput material screening, Chemistry of Materials, 28, (1), 30-34, DOI: 10.1021/acs.chemmater.5b03794
  7. He, G., Huang, J., Liu, W., Wang, X., Chen, H., Sun, X. (2012) ZnO–Bi2O3/graphene oxide photocatalyst with high photocatalytic performance under visible light, Materials Technology, 27 (4), 278-283, DOI: 10.1179/1753555712Y.0000000024
  8. Bilici, Z., Guler, P., Ozay, Y., Yilmaz, S., Yatmaz, H.C., Dizge, N. (2021) Photocatalytic activity of (Er2O3) x (Yb2O3) y (Bi2O3) 1-xy ternary compounds used as heterogeneous semiconductor, Materials Science and Engineering: B, 271, 115250, DOI: 10.1016/j.mseb.2021.115250
  9. Negash, A., Derseh, L. M., Tedla, A., Yassin, J. M. (2024) Eco-friendly synthesis of CuO/Bi2O3 nanocomposite for efficient photocatalytic degradation of Rhodamine B dye, Scientific Reports, 14 (1), 23393, DOI: 10.1038/s41598-024-74408-2
  10. Sun, D., Zhu, S., Ji, Z., Chen, X., Wu, J., Liu, H., Ling, Y., Hosseini-Bandegharaei, A., Li, Z., Liu, Q. (2025) Construction of Er2O3/ZnIn2S4 heterojunction with enhanced oxygen vacancies and upconversion luminescence property for photocatalytic CO2 reduction, Fuel, 400, 135791, DOI: 10.1016/j.fuel.2025.135791
  11. Lu, K.-Q., Li, Y.-H., Tang, Z.-R., Xu, Y.-J. (2021) Roles of graphene oxide in heterogeneous photocatalysis, ACS Materials Au, 1 (1), 37-54, DOI: 10.1021/acsmaterialsau.1c00022
  12. Ani, P.C., Zeitoun, Z., Al-Abedi, H.J., Smith, J. D. (2026) Graphene Synthesis: A Reactor-Oriented Review of Conventional and Emerging Production Methods, Chemical Engineering and Processing-Process Intensification, 22, 110752, DOI: 10.1016/j.cep.2026.110752
  13. Ani, P.C., Al-Abedi, H.J., Smith, J.D., Zeitoun, Z. (2025). Comparative Morphological and Thermal Analysis of Biochar from Oak, and from Oak, Pine and RDF Blends, in a Downdraft Gasifier, Fuels, 6 (3), 73, DOI: 10.3390/fuels6030073
  14. Ani, P.C., Alhameedi, H., Al-Abedi, H.J., Al-Rubaye, H., Zeitoun, Z., Ewuzie, U., Smith, J.D. (2025) The Comprehensive Quantification and Characterization of Oak Biochar Produced via a Gasification Process Using a Downdraft Reactor, Fuels, 6 (3), 51, DOI: 10.3390/fuels6030051
  15. Cole, T., Ani, P., Jasim, A., Zeitoun, Z., Smith, J. (2025). Process intensification in reverse flow reactors to boost various industrial applications: A review, Chemical Engineering and Processing-Process Intensification, 208, 110097, DOI: 10.1016/j.cep.2024.110097
  16. Saed, U.A., Ali, A.H., Saoud, A.A., Zeitoun, Z. (2025) Enhanced Adsorption of Brilliant Green Dye Using Barium Ferrite/Graphene Oxide Nanocomposites, Bulletin of Chemical Reaction Engineering & Catalysis, 20 (4), 683-693, DOI: 10.9767/bcrec.20453
  17. Rajaji, U., Manavalan, S., Chen, S.-M., Chinnapaiyan, S., Chen, T.-W., Ramalingam, R.J. (2019) Facile synthesis and characterization of erbium oxide (Er2O3) nanospheres embellished on reduced graphene oxide nanomatrix for trace-level detection of a hazardous pollutant causing Methemoglobinaemia, Ultrasonics Sonochemistry, 56, 422-429, DOI: 10.1016/j.ultsonch.2019.02.023
  18. Astuti, Y., Elesta, P.P., Widodo, D.S., Widiyandari, H., Balgis, R. (2020) Hydrazine and urea fueled-solution combustion method for Bi2O3 synthesis: characterization of physicochemical properties and photocatalytic activity, Bulletin of Chemical Reaction Engineering & Catalysis, 15 (1), 104-111, DOI: 10.9767/bcrec.15.1.5483.104-111
  19. Wang, C., Liu, H., Wang, G., Fang, H., Yuan, X., Lu, C. (2022) Photocatalytic removal of metronidazole and Cr (Ⅵ) by a novel Zn3In2S6/Bi2O3 S-scheme heterojunction: Performance, mechanism insight and toxicity assessment, Chemical Engineering Journal, 450, 138167, DOI: 10.1016/j.cej.2022.138167
  20. Yu, C., Dong, S., Feng, J., Hu, L., Li, Y., Sun, J. (2014) Controlled synthesis of uniform BiVO4 microcolumns and advanced visible-light-driven photocatalytic activity for the degradation of metronidazole-contained wastewater, Environmental Science and Pollution Research, 21 (4), 2837-2845, DOI: 10.1007/s11356-013-2224-6
  21. Rahman, M.S., Suvo, M.A.H., Islam, M., Noor, A.R., Yeachin, N., Bhuiyan, M. A. (2024) Fast and efficient removal of metronidazole from aqueous solution using graphene oxide (GO) supported nitrogen (N) doped zinc oxide (ZnO) nanoparticles. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 690, 133660, DOI: 10.1016/j.colsurfa.2024.133660
  22. Vekhande, H.N., Bagawade, J.A. (2026) Synthesis and characterization of graphene oxide using a modified Hummers method for enhanced quality and yield, Fullerenes, Nanotubes and Carbon Nanostructures, 34 (3), 251-257, DOI: 10.1080/1536383X.2025.2530136
  23. Wang, H., Zhang, L., Chen, Z., Hu, J,, Li, S., Wang, Z., Liu, J., Wang, X. (2014) Semiconductor heterojunction photocatalysts: design, construction, and photocatalytic performances, Chemical Society Reviews, 43 (15), 5234-5244, DOI: 10.1039/c4cs00126e
  24. Henderson, M.A. (2011) A surface science perspective on TiO2 photocatalysis, Surface Science Reports, 66 (6-7), 185-297, DOI: 10.1016/j.surfrep.2011.01.001
  25. Kamat, P.V. (2011) Graphene-based nanoassemblies for energy conversion, The Journal of Physical Chemistry Letters, 2 (3), 242-251, DOI: 10.1021/jz101639v
  26. Zhang, N., Zhang, Y., Xu, Y.-J. (2012) Recent progress on graphene-based photocatalysts: current status and future perspectives, Nanoscale, 4 (19), 5792-5813, DOI: 10.1039/C2NR31480K
  27. Li, X., Yu, J., Wageh, S., Al‐Ghamdi, A.A., Xie, J. (2016). Graphene in photocatalysis: a review, Small, 12 (48), 6640-6696, DOI: 10.1002/smll.201600382
  28. Yang, P., Yang, X., Liu, W., Guo, R., Yao, Z. (2023) Graphene-based electrocatalysts for advanced energy conversion, Green Energy & Environment, 8 (5), 1265-1278, DOI: 10.1016/j.gee.2022.06.008
  29. Ramalingam, G., Perumal, N., Priya, A., Rajendran, S. (2022) A review of graphene-based semiconductors for photocatalytic degradation of pollutants in wastewater, Chemosphere, 300, 134391, DOI: 10.1016/j.chemosphere.2022.134391
  30. Khan, A.U.R., Ramzan, M., Alanazi, S.J.F., Al-Mohaaimeed, A.M., Ali, S., Imran, M., Majid, M.A., Sarfraz, M.H. (2024) Structural, Optical, Electrical and Photocatalytic Investigation of n-Type Zn2+-Doped α-Bi2O3 Nanoparticles for Optoelectronics Applications, ACS Omega, 9 (21), 22650-22659, DOI: 10.1021/acsomega.3c10521
  31. Williams, D.B., Carter, C.B. (1999) Transmission electron microscopy-A textbook for materials science, Vol. 1, Second Edition, Springer
  32. Thiruppathi, A.R., Sidhureddy, B., Boateng, E., Soldatov, D.V., Chen, A. (2020) Synthesis and electrochemical study of three-dimensional graphene-based nanomaterials for energy applications, Nanomaterials, 10 (7), 1295, DOI: 10.3390/nano10071295
  33. El-Khair, M.A.A., Abo El Naga, A.O., Elwakeel, K.Z., Elgarahy, A.M., Priya, A.K., Yadav, K.K., Morshedy, A.S. 2025) The promise of graphene-based photocatalytic materials for wastewater remediation: A scoping review, Coordination Chemistry Reviews, 544, 216961, DOI: 10.1016/j.ccr.2025.216961
  34. Dreyer, D.R., Park, S., Bielawski, C.W., Ruoff, R.S. (2010) The chemistry of graphene oxide, Chemical Society Reviews, 39 (1), 228-240, DOI: 10.1039/B917103G
  35. Tale, B., Nemade, K., Tekade, P. (2021) Graphene based nano-composites for efficient energy conversion and storage in Solar cells and Supercapacitors: A Review, Polymer-Plastics Technology and Materials, 60 (7), 784-797, DOI: 10.1080/25740881.2020.1851378
  36. Jafari, E., Tamimzadeh, A., Farhadian, M., Nazar, A.R.S. (2025) Visible-light photocatalytic degradation of metronidazole using an S-scheme amino acid glycine–modified TiO2/Fe3O4 heterojunction immobilized on chitosan–Polyacrylonitrile in a batch Photoreactor, International Journal of Biological Macromolecules, 328, Part. 1, 147442, DOI: 10.1016/j.ijbiomac.2025.147442
  37. Lykos, C., Kourkouta, T., Konstantinou, I. (2023) Study on the photocatalytic degradation of metronidazole antibiotic in aqueous media with TiO2 under lab and pilot scale, Science of The Total Environment, 870, 161877, DOI: 10.1016/j.scitotenv.2023.161877
  38. Bagum, M., Islam, S., Khan, E.A., Khandaker, J.I., Ahmed, F. (2023) Degradation of Metronidazole from Aqueous Environment Using Hydrothermally Synthesized ZnO, N‐Doped ZnO, and ZnO/AC Nanoparticles, Advances in Condensed Matter Physics, 2023 (1), 8706698, DOI: 10.1155/2023/8706698
  39. Al-Gheethi, A., Sundram, N., Crane, R., Alburihi, A., Maya, R., Mohamed, S.R., Al-Shaibani, M.M., Noman, E.A., Ponnusamy, S.K., Kamil, N.A.F.M. (2022) Metronidazole photocatalytic degradation by zinc oxide nanoparticles synthesized in watermelon peel extract; advanced optimization, simulation and numerical models using machine learning applications, Environmental Research, 212, 113537, DOI: 10.1016/j.envres.2022.113537
  40. Yeganeh, M., Sobhi, H.R., Esrafili, A. (2022) Efficient photocatalytic degradation of metronidazole from aqueous solutions using Co/g-C3N4/Fe3O4 nanocomposite under visible light irradiation, Environmental Science and Pollution Research, 29 (17), 25486-25495, DOI: 10.1007/s11356-021-17077-2
  41. Yazdanpanah, G., Heidari, M.R., Amirmahani, N., Nasiri, A. (2023) Heterogeneous Sono-Fenton like catalytic degradation of metronidazole by Fe3O4@ HZSM-5 magnetite nanocomposite, Heliyon, 9 (6), DOI: 10.1016/j.heliyon.2023.e16461

Last update:

No citation recorded.

Last update:

No citation recorded.