Green-synthesized ZrO₂ Nanoparticles for Congo Red Adsorption: Machine Learning Prediction and Multi-criteria Optimization
J. Environ. Nanotechnol., Volume 15, No 3 (September 2026) pp. 648-663
Abstract
Zirconium dioxide (ZrO₂) nanoparticles were synthesized from zirconyl chloride octahydrate using Toddalia asiatica leaf extract through an environmentally sustainable route and evaluated for Congo Red (CR) adsorption. XRD, FTIR, SEM–EDX, TGA, and XRF analyses confirmed the crystalline structure, morphology, surface functional groups, elemental composition, and thermal stability of the synthesized nanoparticles. Adsorption performance was investigated using an integrated Taguchi–ANOVA–PSI–PIV–CFANN framework. ANOVA revealed that ZrO₂ dosage predominantly influenced CR removal, whereas initial concentration and dosage governed adsorption capacity. PSI–PIV identified Run 27 at 75 mg L⁻¹ CR, 90 min, 40 °C and 0.25 g L⁻¹ ZrO₂ as the best experimental compromise, achieving 63.56% removal efficiency and the experimentally calculated adsorption capacity. CFANN–PSI–PIV predicted an optimum at 75 mg L⁻¹, 90 min, 50 °C, and 0.25 g L⁻¹, with 67.2169% removal efficiency and the corresponding predicted adsorption capacity. The latter condition represents a model-predicted optimum. These findings demonstrate that green-synthesized ZrO₂ nanoparticles, combined with data-driven optimization, offer a promising approach for treating CR-contaminated wastewater.
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Reference
Amale, A. B., Satishkumar, P., Bhagat, P. R., Motghare, M. S. and Krishnaraj, C., Green Synthesis of ZnO Nanoparticles Using Azadirachta indica Leaf Extract for Rapid Catalytic Degradation of Organic Pollutants, J. Environ. Nanotechnol., 15(2), 151–161 (2026).
https://doi.org/10.13074/jent.2026.06.2612082
Chinnusamy, C. and Thiyagarajan, R., Investigation of BaZrO3 Nanoparticles for Photocatalytic Activity and the Effects of Y-doping, J. Environ. Nanotechnol., 13(3), 456-466 (2024).
https://doi.org/10.13074/jent.2024.09.243849
Das, R. S., Kumar, A., Wankhade, A. V. and Peshwe, D. R., ZrO2@chitosan composite for simultaneous photodegradation of three emerging contaminants and antibacterial application, Carbohydrate Polym., 278, 118940 (2022).
https://doi.org/10.1016/j.carbpol.2021.118940
Gaddala, B., Devi, K. V., Balakrishnan, V., Sundramurthy, V. P., Hariprabhu, M., Mayakannan, S., Kadaikunnan, S. and Khaled, J. M., Evaluation of detoxification performance of Pithecellobium dulce seed pod powder upon acid treatment: removal of reactive red 195-A dye and kinetic analysis, Zeitschrift für Physikalische Chemie, 239(6), 885–910 (2025).
https://doi.org/10.1515/zpch-2024-0879
Halder, P., Mondal, I., Mukherjee, A., Biswas, S., Sau, S., Mitra, S., Paul, B. K., Mondal, D., Chattopadhyay, B. and Das, S., Te4+ and Er3+ doped ZrO2 nanoparticles with enhanced photocatalytic, antibacterial activity and dielectric properties: A next generation of multifunctional material, J. Environ. Manage., 359, 120985 (2024).
https://doi.org/10.1016/j.jenvman.2024.120985
Joshi, A. J., Bhoi, B., Singh, D. K. and Chandra, V., Solar responsive CQD/ZrO2 nanocomposites for rapid degradation of Reactive Red-120, Mater. Chem. Phys., 360, 132565 (2026).
https://doi.org/10.1016/j.matchemphys.2026.132565
Kathirvel, A., Srinivasan, R., Harini, S., Ranjith, N., Kumar, G. S., Lalithambigai, K., Atchudan, R., Habila, M. A., Aljuwayid, A. M. and Yun, H. K., Eco-Friendly Synthesis of Zirconium Dioxide Nanoparticles from Toddalia asiatica: Applications in Dye Degradation, Antioxidant and Antibacterial Activity, Nanomater., 15(2), 84 (2025).
https://doi.org/10.3390/nano15020084
Li, S., Zhang, H., Xiang, B., Chen, G., Huang, J., Mo, Y., Zhong, C., Xiang, D. and Wu, J., Novel Ag-m-t-ZrO2 nanocomposite photocatalyst derived from NH2-UiO-66 with enhanced degradation of dye wastewater under visible light and antibacterial performance, Colloids Surf. A: Physicochem. Eng. Aspects, 747, 140890 (2026).
https://doi.org/10.1016/j.colsurfa.2026.140890
Mungle, N. P., Deshmukh, M. S., Satishkumar, P., Talodhikar, V., Kakade, N. T., Clement, M. and Gounder, K. N., Green Synthesis of MnFe₂O₄ Spinel Nanoparticles Using Camellia sinensis Extract: Optical Bandgap Engineering and Sunlight-driven Photocatalytic Wastewater Remediation, J. Environ. Nanotechnol., 15(2), 73–89 (2026).
https://doi.org/10.13074/jent.2026.06.2612103
Nadesan, A., Subramanian, P., Amaladoss, N., Sivaraman, R. M., Sudhakar, S. and Taras, T., Rubidium-doped zirconia nanoparticles: Green synthesis, structural characterization, and enhanced photocatalytic degradation of malachite green dye, Next Nanotechnol., 10, 100617 (2026).
https://doi.org/10.1016/j.nxnano.2026.100617
Odongo, E. A., Mutai, P. C., Amugune, B. K., Mungai, N. N., Akinyi, M. O. and Kimondo, J., Evaluation of the antibacterial activity of selected Kenyan medicinal plant extract combinations against clinically important bacteria, BMC Complement. Med. Ther., 23(1), 100 (2023).
https://doi.org/10.1186/s12906-023-03939-4
Paul, S. R., Das, T., Debnath, A., Misra, T. K. and Chellam, P. V., Enhanced sequestration of malachite green dye from aqueous medium using zirconium oxide modified biochar from aegle marmelos: mechanism, reusability, and economic evaluation, J. Ind. Chem. Soc., 103(9), 102895 (2026).
https://doi.org/10.1016/j.jics.2026.102895
Qi, W., Yang, Y., Du, J., Yang, J., Guo, L. and Zhao, L., Highly photocatalytic electrospun Zr/Ag Co-doped titanium dioxide nanofibers for degradation of dye, J. Colloid Interf. Sci., 603, 594–603 (2021).
https://doi.org/10.1016/j.jcis.2021.06.109
Rajeswaran, P., Balaramesh, P., Vijayakumar, B., Muralidharan, V. P., Subha, V. and Selvarani, V., Ficus carica Fruit Extract Mediated Synthesis of ZrO2 Nanoparticles for Enhanced Photocatalytic Degradation and Environmental Remediation, Waste Biomass Valoriz., 17(1), 85–99 (2026).
https://doi.org/10.1007/s12649-025-03097-3
Rajput, K., Vazquez, C. J., Jorge, S. A. B., Dev, S. M. and Crick, C. R., Recyclable and eco-compatible polymer composite nanofibers for broad-spectrum dye remediation, RSC Appl. Polym., 4(2), 725–735 (2026).
https://doi.org/10.1039/d5lp00307e
Ramalakshmi, P., Annapoorani, P., Rekha, A., Vijayan, R. and Arjun, P., Identification of Compounds Using Toddalia asiatica Analytical Methods with Molecular Docking Insights into PI3KA And EGFR, Rasayan J. Chem., 19(1), 294–308 (2026).
https://doi.org/10.31788/RJC.2026.1919562
Rana, R., Ahmad, W., Hawwal, M. F., Ansari, I. A., Kumar, S. and Ahmed, S., Nifedipine and metronidazole photodegradation using sustainable Raphanus sativus leaf extract mediated zirconia nanoparticles: A novel green solution for pharmaceutical waste treatment, Environ. Progress Sustainable Energy, 70523 (2026).
https://doi.org/10.1002/ep.70523
Rao, D. P., Krishnasamy, V. D., Selvaraju, M., Sundramurthy, V. P., Kandavalli, S. R., Chitra, M. S., Sivasamy, N. and Thirumoorthy, P., Adsorptive removal of cadmium from electroplating wastewater using hybrid composite of thiol-grafted seed gum of Tamarindus indica and Teff hay biocarbon, Zeitschrift für Physikalische Chemie, 239(5), 633–654 (2025).
https://doi.org/10.1515/zpch-2024-0715
Senthilkumar, N., Karthikeyan, K., Dhamodaran, M., Vijayan, V., Jeevitha, T. U., Eswaramoorthy, N., Chellamuthu, K. and Sasikumar, A., Electrospun PVA/ZrO2, PVA/CuO, and PVA/α-Fe2O3 nanocomposites: A comparative study on photocatalytic activity, Vacuum, 252, 115417 (2026).
https://doi.org/10.1016/j.vacuum.2026.115417
Sharma, D., Bharti, R., Kaushik, P., Sharma, R. and Sutradhar, M., Plant-Assisted Synthesis of ZrO2 Nanoparticles Using Cycas revoluta Extract for Doxycycline Removal from Aqueous Solutions, Appl. Sci., 16(10), 4714 (2026).
https://doi.org/10.3390/app16104714
Sharma, G., AlGarni, T. S., Kumar, P. S., Bhogal, S., Kumar, A., Sharma, S., Naushad, M., ALOthman, Z. A. and Stadler, F. J., Utilization of Ag2O–Al2O3–ZrO2 decorated onto rGO as adsorbent for the removal of Congo red from aqueous solution, Environ. Res., 197, 111179 (2021).
https://doi.org/10.1016/j.envres.2021.111179
Sharmiladevi, S., Ramesh, N., Prabhu, S. V and Mayakannan, S., Microwave-assisted functionalized biosorbent preparation using seed gum of Tamarindus indica: characterization and evaluation of Cr(VI) removal potency from tannery effluents, Biomass Convers. Biorefin., 14(12), 13533–13545 (2024).
https://doi.org/10.1007/s13399-024-05667-2
Shinde, H. M., Kamble, R. J., Vhanmore, B. D. and Mane, C. B., An innovative fabrication of g-C3N4-ZrO2 nanocomposite with enhanced photocatalytic degradation of methylene blue under UV–visible light, J. Opt., 55(3), 2304–2318 (2026).
https://doi.org/10.1007/s12596-024-02394-9
Shokoohi, R., Salari, M., Safari, R., Zolghadr Nasab, H. and Shanehsaz, S., Modelling and optimisation of catalytic ozonation process assisted by ZrO2-pumice/H2O2 in the degradation of Rhodamine B dye from aqueous environment, Int. J. Environ. Anal. Chem., 101(15), 2629–2653 (2021).
https://doi.org/10.1080/03067319.2019.1704748
Sismanoglu, S. and Buran, E., Azo dye adsorption on ZrO2 and natural organic material doped ZrO2, Sci. Rep., 15(1), 2842 (2025).
https://doi.org/10.1038/s41598-024-83639-2
Tahir, S., Waheed, F., Akram, M., Salman, M., Farooq, U., Saleem, S. and Ehsan, A., Vanadium-Doped Zirconia as an Efficient Visible-Light Photocatalyst for Advanced Treatment of Dye-Loaded Wastewater, Iran. J. Catal., 16(2), 222–241 (2026).
https://doi.org/10.57647/ijc.2026.1602.15
Varma, V. K. C., Rathinam, R., Suresh, V., Naveen, S., Satishkumar, P., Abdulrahman, I. S., Salman, H. M., Singh, P. and Kumar, J. A., Urban waste water management paradigm evolution: Decentralization, resource recovery, and water reclamation and reuse, Environ. Qual. Manage., 33(4), 523–540 (2024).
https://doi.org/10.1002/tqem.22109
Wahba, M. A. and Yakout, S. M., Microwave-synthesized ZrO2/ZnO heterostructures: fast and high charge separation solar catalysts for dyes-waste degradation, J. Sol-Gel Sci. Technol., 104(2), 330–341 (2022).
https://doi.org/10.1007/s10971-022-05936-4
Zhu, Y., Wang, Y. and Yan, X., Preparation of Chitosan-Coated Toddalia asiatica (L.) Lam Extract Microcapsules and Its Effect on Coating Antibacterial Properties, Coat., 14(8), 942 (2024a).
https://doi.org/10.3390/coatings14080942
Zhu, Y., Wang, Y. and Yan, X., The Effects of Urea–Formaldehyde Resin-Coated Toddalia asiatica (L.) Lam Extract Microcapsules on the Properties of Surface Coatings for Poplar Wood, Coat., 14(8), 1011 (2024b).
