Sustainable W–BiVO₄ Nanocatalysts for Visible-light Removal of Reactive Black 5: Physicochemical Characterization and Multiresponse Optimization
J. Environ. Nanotechnol., Volume 15, No 3 (September 2026) pp. 323-340
Abstract
This study reports the green synthesis of pristine BiVO₄ and tungsten-doped BiVO₄ (W–BiVO₄) nanocatalysts using dragon-fruit-peel extract for the visible-light degradation of Reactive Black 5 (RB5). The novelty lies in integrating waste-derived green synthesis, multiresponse statistical optimization, machine-learning prediction, and kinetic evaluation within a single RB5-treatment framework. The W–BiVO₄ nanoparticles exhibited irregular rod-like and ellipsoidal morphologies with a mean particle size of 48.6 ± 10.4 nm. SEM–EDX confirmed the presence of Bi, V, O, and W, although this analysis alone does not conclusively establish substitutional incorporation of W into the BiVO₄ lattice. The synthesized BiVO₄ exhibited an estimated optical band gap of 2.55 eV, supporting visible-light activation. The photocatalytic performance of W–BiVO₄ was investigated using a 29-run Box–Behnken design by varying initial RB5 concentration, catalyst dosage, initial pH, and W-doping level. The highest experimental performance was 93.40% RB5 removal with an apparent pseudo-first-order rate constant of 0.01947 min⁻¹ at 20 mg L⁻¹ RB5, 1.20 g L⁻¹ catalyst dosage, pH 6, and 3 wt.% W doping. The quadratic RSM models were statistically significant and achieved R² values of 0.9991 for RB5 removal efficiency and 0.9831 for the apparent pseudo-first-order rate constant. Multiresponse optimization predicted 93.51% RB5 removal and an apparent pseudo-first-order rate constant of 0.02003 min⁻¹ at an initial RB5 concentration of 20.68 mg L⁻¹, W–BiVO₄ dosage of 1.162 g L⁻¹, initial pH of 5.30, and W-doping level of 3.44 wt.%, with an overall desirability of 1.000. Among six machine-learning models evaluated using leave-one-out cross-validation, Gaussian process regression provided the best prediction of RB5 removal efficiency (R² = 0.991), whereas support vector regression provided the best prediction of the apparent pseudo-first-order rate constant (R² = 0.924). These findings demonstrate the potential of combining green W–BiVO₄ synthesis, experimental optimization, and machine-learning prediction for visible-light treatment of RB5-containing wastewater.
Full Text
Reference
Abhale, Y., Patel, K., Paul, R. K., Mishra, S. R., Roy, S., Ahmaruzzaman, M., Ban, T. K., Kumar, D. and Ghotekar, S., Novel bio-inspired fabrication of BiVO4 nanoparticles and their solar light-aided photocatalytic activity for metronidazole antibiotic degradation, J. Sol-Gel Sci. Technol., 115(3), 1580–1597 (2025).
https://doi.org/10.1007/s10971-025-06872-9
Ameenudeen, S., Unnikrishnan, S. and Ramalingam, K., Statistical optimization for the efficacious degradation of reactive azo dyes using Acinetobacter baumannii JC359, J. Environ. Manage., 279, 111512 (2021).
https://doi.org/10.1016/j.jenvman.2020.111512
Anishia, S. R. and Rajeswari, S., Green Synthesis and Multifunctional Applications of Moringa Oleifera-enhanced TiO2 Nanocomposites, J. Environ. Nanotechnol., 14(1), 7–17 (2025).
https://doi.org/10.13074/jent.2025.03.2511225
Auxilia Ruby, S., Felicita Florence, J. and Asia Thabassoom, H., Green Synthesis of Tungsten Trioxide Nanoparticles Using Selenicereus undatus Peel Extract and their Characterization, J. Environ. Nanotechnol., 14(1), 415–424 (2025).
https://doi.org/10.13074/jent.2025.03.2441148
Banerjee, S., Mukherjee, A., Dhak, D., Madhogaria, B., Chakraborty, S., Kundu, A. and Dhak, P., Facile biosynthesis of iron oxide nanoparticles from Parthenium hysterophorus extract and investigating their bioactive and photocatalytic applications, 3 Biotech, 15(12), 422 (2025).
https://doi.org/10.1007/s13205-025-04581-2
Dash, A., Ragavendran, C. and Rajendran, R., Biogenic Nickel Oxide Nanoparticles: Synthesis, Characterization and Biomedical Potential, Mol. Biotechnol., 68(2), 872–895 (2026).
https://doi.org/10.1007/s12033-025-01413-9
Hadkar, V. M., Sishu, N. K., Jayabharathi, S. P., Sharmila, A. and Selvaraj, C. I., Biogenic synthesis of Albizia lucidior mediated magnetite nanoparticles (Fe3O4 NPs): Therapeutic applications and photocatalytic activity, Biocatal. Agri. Biotechnol., 67, 103676 (2025).
https://doi.org/10.1016/j.bcab.2025.103676
Kistan, A., Kanchana, V., Mohan, S. and Chitra, M., Green Synthesis of Manganese-Enriched Zinc Oxide Nanoparticles via Dragon Fruit Peel Extracts and their Photocatalytic activity on Methyl Orange, Res. J. Chem. Environ., 29(2), 81–89 (2025).
https://doi.org/10.25303/292rjce081089
Kistan, A., Kanchana, V., Mohan, S. and Chitra, M., Innovative Synthesize of ZrO2 Nanomaterial Using Biodegradable Dragon Fruit Peel Extracts and its Photocatalytic Activity Against Methyl Orange by UV radiation, Rasayan J. Chem., 17(1), 199–206 (2024).
https://doi.org/10.31788/RJC.2024.1718694
Kistan, A., Mahimairaj, P., Mohan, S., Jeevalatha, R. and Sivakumar, P., Novel Synthesis of S-Doped Zno Nanomaterials Using Selenicereus Undatus Peel Extract for Enhanced UV Photocatalytic Degradation of Methyl Orange, Rasayan J. Chem., 19(1), 575–582 (2026).
https://doi.org/10.31788/RJC.2026.1919577
Kothari, M. S., Vegad, K. G., Shah, K. A. and Aly Hassan, A., An artificial neural network combined with response surface methodology approach for modelling and optimization of the electro-coagulation for cationic dye, Heliyon, 8(1), e08749 (2022).
https://doi.org/10.1016/j.heliyon.2022.e08749
Kumar, A., Poornima, S. N., Subbulakshmi, R., Selvaraju, M., G, R. K. and Jayabalan, C., Hierarchical green carbon fibers from banana pseudostem for efficient Pb2+ adsorption: Kinetics, isotherms, and machine learning prediction, Interact., 247(1), 188 (2026).
https://doi.org/10.1007/s10751-026-02534-6
Kumar, M. and Vaish, R., Photocatalytic dye degradation using BiVO4-paint composite coatings, Mater. Adv., 3(14), 5796–5806 (2022).
https://doi.org/10.1039/d2ma00316c
Kumar, M., Vaish, R., Elqahtani, Z. M., Kebaili, I., Al-Buriahi, M. S., Sung, T. H., Hwang, W. and Kumar, A., Piezo-photocatalytic activity of Bi2VO5.5 for methylene blue dye degradation, J. Mater. Res. Technol., 21, 1998–2012 (2022).
https://doi.org/10.1016/j.jmrt.2022.09.130
Liu, Z., Hu, Y., Li, C., Zhang, Z., Shen, T., Zeng, D., Guan, R., Zhou, C. and Dong, P., Fabrication of S-scheme heterojunction consisting of W-doped BiVO4 and biperovskite Cs2AgBiBr6 for photocatalytic degradation of antibiotics, J. Colloid Interface Sci., 696, 137892 (2025).
https://doi.org/10.1016/j.jcis.2025.137892
Pramila, S., Mallikarjunaswamy, C., Nagaraju, G., Kavana, C. P., Chandan, S. and Spoorthy, H. P., Green synthesis of bismuth vanadate nanostructures for efficient photocatalytic and biological studies, Nano-Struct. Nano-Obj., 39, 101198 (2024).
https://doi.org/10.1016/j.nanoso.2024.101198
Nalina, R., Latha, K. P. and Nagaraju, G., Swift one-pot biosynthesis of copper-bismuth vanadate Cu3Bi4V2O14 as a novel photocatalyst using Erythroxylum monogynum seed for efficient visible-light-driven dye degradation, Cr (VI) detoxification, eco-phytotoxic assay and dopamine sensing, Ceram. Int., 52(14), 24212–24233 (2026).
https://doi.org/10.1016/j.ceramint.2026.03.459
Rafaela, A. A., Casanova, M. F., Frederico, H. L. M. J., Regina, L. T. E. and Andrade, P. C., Photocatalytic oxidation of textile dye using sugarcane bagasse-Nb2O5 as a catalyst, J. Photochem. Photobiol. A: Chem., 432, 114103 (2022).
https://doi.org/10.1016/j.jphotochem.2022.114103
Rayya, N. W., Etefa, K. T., Yimer, A. A., Muleta, G. G. and Beyene, T. T., Green synthesis of Cu-doped ZnO nanocomposites using Phytolacca Dodecandra root extract to improve photocatalytic and antibacterial activity and extend avocado shelf-life, Sci. Rep., 16(1), 2225 (2026).
https://doi.org/10.1038/s41598-025-31793-6
Rosa, J. M., Guerhardt, F., Ribeiro Júnior, S. E. R., Belan, P. A., Lima, G. A., Santana, J. C. C., Berssaneti, F. T., Tambourgi, E. B., Vanale, R. M. and Araújo, S. A., Modeling and optimization of reactive cotton dyeing using response surface methodology combined with artificial neural network and particle swarm techniques, Clean Technol. Environ. Policy, 23(8), 2357–2367 (2021).
https://doi.org/10.1007/s10098-021-02142-8
Sajid, M. M., Assaedi, H. and Zhai, H., Tungsten doping effect on bismuth vanadate (W-doped BiVO4) under visible-light irradiation for photocatalysis, J. Mater. Sci. Mater. Electron., 35(7), 502 (2024).
https://doi.org/10.1007/s10854-024-12257-5
Salari, M., Nikoo, M. R., Al-Mamun, A., Rakhshandehroo, G. R. and Mooselu, M. G., Optimizing Fenton-like process, homogeneous at neutral pH for ciprofloxacin degradation: Comparing RSM-CCD and ANN-GA, J. Environ. Manage., 317, 115469 (2022).
https://doi.org/10.1016/j.jenvman.2022.115469
Selvinsimpson, S., Eva Gnana Dhana Rani, S., Ganesh Kumar, A., Rajaram, R., Sharmila Lydia, I. and Chen, Y., Photocatalytic activity of SnO2/Fe3O4 nanocomposites and the toxicity assessment of Vigna radiata, Artemia salina and Danio rerio in the photodegraded solution, Environ. Res., 195, 110787 (2021).
https://doi.org/10.1016/j.envres.2021.110787
Silva, M. C. R., Castro-Lopes, S., Jerônimo, A. G., Barbosa, R., Lins, A., Trigueiro, P., Viana, B. C., Araujo, F. P., Osajima, J. A. and Peña-Garcia, R. R., Green Synthesis of Er-Doped ZnO Nanoparticles: An Investigation on the Methylene Blue, Eosin, and Ibuprofen Removal by Photodegradation, Mol., 29(2), 391 (2024).
https://doi.org/10.3390/molecules29020391
Tsay, C. Y., Chung, C. Y., Chen, C. Y., Chang, Y. C., Chang, C. J. and Wu, J. J., Enhanced Photocatalytic Performance of Visible-Light-Driven BiVO4 Nanoparticles through W and Mo Substituting, Catal., 13(3), 475 (2023).
https://doi.org/10.3390/catal13030475
Xiaocui, W. U., Chen, K., Xue, W., Sun, F., Yang, H. and Cui, Z., From data to catalysis: A hybrid experimental verification-machine learning framework for predicting and enhancing visible-light-driven RhB degradation by template-synthesized g-C3N4, J. Alloys and Compd., 1052, 186129 (2026).
https://doi.org/10.1016/j.jallcom.2026.186129
Xue, Y., Tang, W., Gu, H., Wei, M., Guo, E., Lu, Q. and Pang, Y., Flexible Bi2MoO6/N-doped carbon nanofiber membrane enables tetracycline photocatalysis for environmentally safe growth of Vigna radiata, J. Alloys Compds, 902, 163860 (2022).
https://doi.org/10.1016/j.jallcom.2022.163860
Yan, Y., Ni, T., Du, J., Li, L., Fu, S., Li, K. and Zhou, J., Green synthesis of balsam pear-shaped BiVO₄/BiPO₄ nanocomposite for degradation of organic dye and antibiotic metronidazole, Dalton Trans., 47, 6089–6101 (2018).
https://doi.org/10.1039/C8DT00408K
Zaharieva, K., Dimova, S., Ublekov, F. and Penchev, H., Natural Zeolites-Supported Green-Synthesized CeO2@Polybenzimidazole Hybrid Materials for Dye Degradation, Eng. Proc., 117(1), 24 (2026).
https://doi.org/10.3390/engproc2025117024
Zhao, G., Ding, J., Zhou, F., Zhao, Q., Wang, K., Chen, X. and Gao, Q., Insight into a novel microwave-assisted W doped BiVO4 self-assembled sphere with rich oxygen vacancies oriented on rGO (W-BiVO4-x/rGO) photocatalyst for efficient contaminants removal, Separat. Purifi. Technol., 277, 119610 (2021).
