Synergistic heterogeneous electro-Fenton process using iron-loaded bentonite for binary dyes degradation from wastewater
Original scientific paper
DOI:
https://doi.org/10.5599/jese.3240Keywords:
Natural clay, iron incorporation, heterogenous catalyst, mixed dyes, electrochemical removal, wastewater treatmentAbstract
This study examines the impact of operational parameters on the performance of a heterogeneous electro-Fenton process for removing a binary mixture of malachite green (MG) and methylene blue (MB) using iron-loaded bentonite clay (Fe-Bent.) particles as a heterogeneous catalyst. The effects of current density (j), Fe-Bent.* dosage (Bent. quantity variable) and Fe*-Bent. dosage (iron concentration variable), were investigated. Brunauer-Emmett-Teller analysis, X-ray diffraction, X-ray fluorescence and scanning electron microscopy were used to extensively evaluate the synthesized catalyst, confirming the effective incorporation and uniform distribution of iron within the bentonite clay. The results showed that increase of j enhanced dye removal efficiency to over 95 % for MG and 90 % for MB at 20 mA cm-². Furthermore, increasing the dose of Fe-Bent.* from 1 to 3 g improved the overall removal efficiency, although this was accompanied by a decrease in adsorption capacity and a deviation from ideal kinetic behaviour at higher loadings. Fe*-Bent. dosage with a variable iron concentration from (0.1 to 0.2 mM) exhibited the highest removal efficiency, while increasing to 0.3 mM resulted in decreased process performance. The comparison results showed that the electro-Fenton process alone achieved limited removal, whereas bentonite adsorption alone provided high but incomplete removal. In contrast, the heterogeneous electro-Fenton process achieved the highest efficiency (98.06 % for MG and 91.14 % for MB, with COD values of 84.53 % for MG and 79.82 % for MB), with the lowest iron leaching (<0.1 ppm), well below regulatory limits. These results demonstrate the clear advantage of the heterogeneous electro-Fenton process for efficient and environmentally friendly removal of mixed dye pollutants.
Downloads
References
[1] M. Akhtar, M. Sarfraz, M. Ahmad, Use of low-cost adsorbent for wastewater treatment : Recent progress, new trend and future perspectives, Desalination and Water Treatment 321 (2025) 100914. https://doi.org/10.1016/j.dwt.2024.100914 DOI: https://doi.org/10.1016/j.dwt.2024.100914
[2] M. Y. D. Alazaiza, T. M. Alzghoul, M. B. Ramu, S. S. A. Amr, M. F. M. Abushammala, D. E. Nassani, Global perspectives on industrial wastewater management: A bibliometric analysis of research output, Journal of Hazardous Materials Advances 17 (2025) 100567. https://doi.org/10.1016/j.hazadv.2024.100567 DOI: https://doi.org/10.1016/j.hazadv.2024.100567
[3] W. Musie, G. Gonfa, Freshwater resource, scarcity, water salinity challenges and possible remedies: A review, Heliyon 9 (2023) e18685. https://doi.org/10.1016/j.heliyon.2023.e18685 DOI: https://doi.org/10.1016/j.heliyon.2023.e18685
[4] S. S. Abu Amr, M. S. S. Abujazar, M. Y. D. Alazaiza, A. Albahnasawi, F. Omer, Heavy metals removal from industrial wastewater using date seeds powder and aluminum chloride-based hybrid natural/chemical coagulation, Desalination and Water Treatment 318 (2024) 100392. https://doi.org/10.1016/j.dwt.2024.100392 DOI: https://doi.org/10.1016/j.dwt.2024.100392
[5] E. Amdeha, Biochar-based nanocomposites for industrial wastewater treatment via adsorption and photocatalytic degradation and the parameters affecting these processes, Biomass Con¬version and Biorefinery 14 (2023) 23293-23318. https://doi.org/10.1007/s13399-023-04512-2 DOI: https://doi.org/10.1007/s13399-023-04512-2
[6] R. Naidu, B. Biswas, I. R. Willett, J. Cribb, B. Kumar Singh, C. Paul Nathanail, F. Coulon, K. T. Semple, K. C. Jones, A. Barclay, R. John Aitken, Chemical pollution: A growing peril and potential catastrophic risk to humanity, Environment International 156 (2021) 106616. https://doi.org/10.1016/j.envint.2021.106616 DOI: https://doi.org/10.1016/j.envint.2021.106616
[7] Z. I. Abbas, A. S. Abbas, Optimization of the electro-fenton process for cod reduction from refinery wastewater, Environmental Engineering and Management Journal 19 (2021) 2029-2037. https://doi.org/10.30638/eemj.2020.192 DOI: https://doi.org/10.30638/eemj.2020.192
[8] Kusumlata, B. Ambade, A. Kumar, S. Gautam, Sustainable Solutions: Reviewing the Future of Textile Dye Contaminant Removal with Emerging Biological Treatments, Limnological Review 24 (2024) 126-149. https://doi.org/10.3390/limnolrev24020007 DOI: https://doi.org/10.3390/limnolrev24020007
[9] M. Ammar, E. Yousef, M.A. Mahmoud, S. Ashraf, J. Baltrusaitis, A Comprehensive Review of the Developments in Electrocoagulation for the Removal of Contaminants from Wastewater, Separations 10 (2023) 337. https://doi.org/10.3390/separations10060337 DOI: https://doi.org/10.3390/separations10060337
[10] A. Eslami, M.R. Khavari Kashani, A. Khodadadi, G. Varank, A. Kadier, P.C. Ma, S. Madihi-Bidgoli, F. Ghanbari, Sono-peroxi-coagulation (SPC) as an effective treatment for pulp and paper wastewater: Focus on pH effect, biodegradability, and toxicity, Journal of Water Process Engineering 44 (2021) 102330. https://doi.org/10.1016/J.JWPE.2021.102330 DOI: https://doi.org/10.1016/j.jwpe.2021.102330
[11] R. H. Salman, E. M. Khudhair, K. M. Abed, A. S. Abbas, Removal of E133 brilliant blue dye from artificial wastewater by electrocoagulation using cans waste as electrodes, Environmental Progress & Sustainable Energy 43 (2024) e14292. https://doi.org/10.1002/ep.14292 DOI: https://doi.org/10.1002/ep.14292
[12] A. G. Saleem, S. M. Al-Jubouri, Separation performance of cationic and anionic dyes from water using polyvinylidene fluoride-based ultrafiltration membrane incorporating polyethylene glycol, Desalination and Water Treatment 319 (2024) 100546. https://doi.org/10.1016/j.dwt.2024.100546 DOI: https://doi.org/10.1016/j.dwt.2024.100546
[13] R. Al-Tohamy, S. S. Ali, F. Li, K. M. Okasha, Y. A. G. Mahmoud, T. Elsamahy, H. Jiao, Y. Fu, J. Sun, A critical review on the treatment of dye-containing wastewater: Ecotoxicological and health concerns of textile dyes and possible remediation approaches for environmental safety, Ecotoxicology and Environmental Safety 231 (2022) 113160. https://doi.org/10.1016/j.ecoenv.2021.113160 DOI: https://doi.org/10.1016/j.ecoenv.2021.113160
[14] E. M. Reda, H. A. Othman, H. Ghazal, A. G. Hassabo, Kinetic and isothermal study of dye absorption using pre-treated natural fabrics using polyamine compounds, Scientific Reports 15 (2025) 3794. https://doi.org/10.1038/s41598-025-86012-z DOI: https://doi.org/10.1038/s41598-025-86012-z
[15] S. Haran, S. K. Ali, Methods for Removing Dyes from Polluted Water; A Review, Journal of Engineering 28 (2022) 70-85. https://doi.org/10.31026/j.eng.2022.09.05 DOI: https://doi.org/10.31026/j.eng.2022.09.05
[16] S. K. Theydan, W. T. Mohammed, An Electrocoagulation Process Operated at Batch Recirculation Mode for Treatment of Refinery Wastewaters: Optimization via Response Surface Methodology, Egyptian Journal of Chemistry 65 (2022) 1361-1372. https://doi.org/10.21608/EJCHEM.2022.146203.6361 DOI: https://doi.org/10.21608/ejchem.2022.146203.6361
[17] N. S . Ali, N. M. Jabbar, S. M. Alardhi, H. S. Majdi, T. M. Albayati, Adsorption of methyl violet dye onto a prepared bio-adsorbent from date seeds: isotherm, kinetics, and thermodynamic studies, Heliyon 8 (2022) e10276. https://doi.org/10.1016/j.heliyon.2022.e10276 DOI: https://doi.org/10.1016/j.heliyon.2022.e10276
[18] M. Tripathi, S. Singh, S. Pathak, J. Kasaudhan, A. Mishra, S. Bala, D. Garg, R. Singh, P. Singh, P. K. Singh, A. K. Shukla, N. Pathak, Recent Strategies for the Remediation of Textile Dyes from Wastewater, Toxics 11 (2023) 940. https://doi.org/10.3390/toxics11110940 DOI: https://doi.org/10.3390/toxics11110940
[19] H. H. Thwaini, R. H. Salman, Phenol removal by electro-Fenton process using a 3D electrode with iron foam as particles and carbon fibre modified with graphene, Journal of Electrochemical Science and Engineering 13 (2023) 537-551. https://doi.org/10.5599/jese.1806 DOI: https://doi.org/10.5599/jese.1806
[20] R. N. Abbas, A. S. Abbas, Kinetics and Energetic Parameters Study of Phenol Removal from Aqueous Solution by Electro-Fenton Advanced Oxidation Using Modified Electrodes with PbO2 and Graphene, Iraqi Journal of Chemical and Petroleum Engineering 23 (2022) 1-8. https://doi.org/10.31699/ijcpe.2022.2.1 DOI: https://doi.org/10.31699/IJCPE.2022.2.1
[21] Z.-L. Pan, X.-F. Qian, Porous carbons for use in electro-Fenton and Fenton-like reactions, New Carbon Materials 37 (2022) 180-195. https://doi.org/10.1016/S1872-5805(22)60578-X DOI: https://doi.org/10.1016/S1872-5805(22)60578-X
[22] A. Deb, J. Rumky, M. Sillanpää, Fenton, Photo-Fenton, and Electro-Fenton Systems for Micropollutant Treatment Processes, in: Advanced Oxidation Processes for Micropollutant Remediation, 1st Edition, CRC Press, 2023. https://doi.org/10.1201/9781003247913-8 DOI: https://doi.org/10.1201/9781003247913-8
[23] N. A. A. Mohammed, A. I. Alwared, M. S. Salman, Decolorization of Reactive Yellow Dye by Advanced Oxidation Using Continuous Reactors, Iraqi Journal of Chemical and Petroleum Engineering 21 (2020) 1-6. https://doi.org/10.31699/ijcpe.2020.2.1 DOI: https://doi.org/10.31699/IJCPE.2020.2.1
[24] O. Assila, Z. Bencheqroun, E. Rombi, T. Valente, A. S. Braga, H. Zaitan, A. Kherbeche, O. S. G. P. Soares, M. F. R. Pereira, A. M. Fonseca, P. Parpot, I. C. Neves, Raw clays from Morocco for degradation of pollutants by Fenton-like reaction for water treatment, Colloids and Surfaces A 679 (2023) 132630. https://doi.org/10.1016/j.colsurfa.2023.132630 DOI: https://doi.org/10.1016/j.colsurfa.2023.132630
[25] J. J. Conde, S. Abelleira, S. Estévez, J. González-Rodríguez, G. Feijoo, M. T. Moreira, Improving the sustainability of heterogeneous Fenton-based methods for micropollutant abatement by electrochemical coupling, Journal of Environmental Management 332 (2023) 117308. https://doi.org/10.1016/j.jenvman.2023.117308 DOI: https://doi.org/10.1016/j.jenvman.2023.117308
[26] P. V. Nidheesh, H. Olvera-vargas, N. Oturan, M. A. Oturan, Heterogeneous Electro-Fenton Process : Principles and Applications, in Electro-Fenton Process, The Handbook of Environmental Chemistry, M. Zhou, M. Oturan, I. Sirés, Eds., Springer, Singapore, 2017. https://link.springer.com/chapter/10.1007/698_2017_72 DOI: https://doi.org/10.1007/698_2017_72
[27] N. Oturan, J. Bo, C. Trellu, M. A. Oturan, Comparative Performance of Ten Electrodes in Electro-Fenton Process for Removal of Organic Pollutants from Water, ChemElectroChem 8 (2021) 3294-3303. https://doi.org/10.1002/celc.202100588 DOI: https://doi.org/10.1002/celc.202100588
[28] F. Sopaj, M. A. Rodrigo, N. Oturan, F. I. Podvorica, J. Pinson, M. A. Oturan, Influence of the anode materials on the electrochemical oxidation efficiency. Application to oxidative degradation of the pharmaceutical amoxicillin, Chemical Engineering Journal 262 (2015) 286-294. https://doi.org/10.1016/j.cej.2014.09.100 DOI: https://doi.org/10.1016/j.cej.2014.09.100
[29] A. R. Flayyih, A. H. Abbar, Treatment of petroleum refinery wastewater by a heterogeneous electro-Fenton process using activated carbon loaded with Fe2O3-CeO2 as a catalyst, Results in Engineering 28 (2025) 108249. https://doi.org/10.1016/j.rineng.2025.108249 DOI: https://doi.org/10.1016/j.rineng.2025.108249
[30] H. Zhang, Y. Yang, D. Ren, L. Wang, X. He, Graphite as anode materials: Fundamental mechanism, recent progress and advances, Energy Storage Materials 36 (2021) 147-170. https://doi.org/10.1016/j.ensm.2020.12.027 DOI: https://doi.org/10.1016/j.ensm.2020.12.027
[31] L. C. Crapina, L. Dzene, J. Brendlé, F. Fourcade, A. Amrane, L. Limousy, Review: Clay-modified electrodes in heterogeneous electro-fenton process for degradation of organic compounds: The potential of structural fe(iii) as catalytic sites, Materials 14 (2021) 7742. https://doi.org/10.3390/ma14247742 DOI: https://doi.org/10.3390/ma14247742
[32] Z. Liu, Y. Zhang, J. Lee, L. Xing, A review of application mechanism and research progress of Fe/montmorillonite-based catalysts in heterogeneous Fenton reactions, Journal of Environmental Chemical Engineering 12 (2024) 112152. https://doi.org/10.1016/j.jece.2024.112152 DOI: https://doi.org/10.1016/j.jece.2024.112152
[33] H. Alihodžić, A. Dozić, I. Šestan, H. Junuzović, Efficiency of Multistep Process of Fenton Oxidation and Bentonite in the Treatment of Ammonia Phenolic Wastewater, International Journal of Scientific Research in Science, Engineering and Technology 10 (2023) 210-217. https://doi.org/10.32628/IJSRSET2310224 DOI: https://doi.org/10.32628/IJSRSET2310224
[34] A. Al-Hammood, Q. Frayyeh, W. Abbas, Iraqi bentonite as natural pozzolan, Magazine of Civil Engineering 116 (2022) 11604. https://doi.org/10.34910/MCE.116.4 DOI: https://doi.org/10.21203/rs.3.rs-437439/v1
[35] Y. Zhang, Z. Chen, P. Wu, Y. Duan, L. Zhou, Y. Lai, F. Wang, S. Li, Three-dimensional heterogeneous Electro-Fenton system with a novel catalytic particle electrode for Bisphenol A removal, Journal of Hazardous Materials 393 (2020) 120448. https://doi.org/10.1016/j.jhazmat.2019.03.067 DOI: https://doi.org/10.1016/j.jhazmat.2019.03.067
[36] S. K. Isalou, M. Ghorbanpour, Catalytic activity of Fe-modified bentonite in heterogeneous photo-Fenton process, Desalination and Water Treatment 162 (2019) 376-382. https://doi.org/10.5004/dwt.2019.24272 DOI: https://doi.org/10.5004/dwt.2019.24272
[37] N. K. Daud, B. H. Hameed, Acid Red 1 dye decolorization by heterogeneous Fenton-like reaction using Fe/kaolin catalyst, Desalination 269 (2011) 291-293. https://doi.org/10.1016/j.desal.2010.11.016 DOI: https://doi.org/10.1016/j.desal.2010.11.016
[38] S. M. Pormazar, A. Dalvand, Heterogeneous electro-Fenton process using a novel catalytic electrode for the degradation of direct dye from aqueous solutions: modeling, optimization, degradation pathway and toxicity evaluation, Applied Water Science 15 (2025) 52. https://doi.org/10.1007/s13201-025-02394-5 DOI: https://doi.org/10.1007/s13201-025-02394-5
[39] A. El Andaloussi, Z. El Ahmadi, Electro-Fenton degradation of Methylene Blue using Graphite/Magnetite cathode, Moroccan Journal of Chemistry 11 (2023) 460-473. https://doi.org/10.48317/IMIST.PRSM/morjchem-v11i2.34910
[40] T. A. Aragaw, A. N. Alene, A comparative study of acidic, basic, and reactive dyes adsorption from aqueous solution onto kaolin adsorbent: Effect of operating parameters, isotherms, kinetics, and thermodynamics, Emerging Contaminants 8 (2022) 59-74. https://doi.org/10.1016/j.emcon.2022.01.002 DOI: https://doi.org/10.1016/j.emcon.2022.01.002
[41] W. M. Gitari, T. Ngulube, V. Masindi, J. R. Gumbo, Defluoridation of groundwater using Fe3+-modified bentonite clay: optimization of adsorption conditions, Desalination and Water Treatment 53 (2015) 1578-1590. https://doi.org/10.1080/19443994.2013.855669 DOI: https://doi.org/10.1080/19443994.2013.855669
[42] D. Tiwari, C. Laldanwngliana, C. H. Choi, S. M. Lee, Manganese-modified natural sand in the remediation of aquatic environment contaminated with heavy metal toxic ions, Chemical Engineering Journal 171 (2011) 958-966. https://doi.org/10.1016/j.cej.2011.04.046 DOI: https://doi.org/10.1016/j.cej.2011.04.046
[43] Y. Huang, H. Ni, S. Rahman, Synthesis, characterization, and electrochemical properties of lithium-based fluorosulfate nanoparticles as cathode for lithium-ion batteries, Ionics 22 (2016) 1775-1780. https://doi.org/10.1007/s11581-016-1720-3 DOI: https://doi.org/10.1007/s11581-016-1720-3
[44] A. Monshi, M. R. Foroughi, M. R. Monshi, Modified Scherrer Equation to Estimate More Accurately Nano-Crystallite Size Using XRD, World Journal of Nano Science and Engineering 02 (2012) 154-160. https://doi.org/10.4236/wjnse.2012.23020 DOI: https://doi.org/10.4236/wjnse.2012.23020
[45] Z. A. Hammood, Z. T. A. Ali, Using Iraqi bentonite for immobilizing metallic nanoparticles synthesized using green antioxidant for penicillin-G, kanamycin, and chloramphenicol removal from aqueous solutions, Desalination and Water Treatment 325 (2026) 101689. https://doi.org/10.1016/j.dwt.2026.101689 DOI: https://doi.org/10.1016/j.dwt.2026.101689
[46] K. Madi, H. Kadji, I. Yahiaoui, A. Amrane, Iron-Modified Bentonite as an Efficient Heterogeneous Electro-Fenton Catalyst for Amoxicillin Degradation, Catalysts 16 (2026) 322. https://doi.org/10.3390/catal16040322 DOI: https://doi.org/10.3390/catal16040322
[47] D. Jóźwiak-Niedźwiedzka, R. Jaskulski, K. Dziedzic, A. Antolik, M. Dąbrowski, Influence of Calcination Temperature and Amount of Low-Grade Clay Replacement on Mitigation of the Alkali-Silica Reaction, Materials 16 (2023) 3210. https://doi.org/10.3390/ma16083210 DOI: https://doi.org/10.3390/ma16083210
[48] H. R. D. Alamery, S. A. Ahmed, Purification and activation of the Iraqi bentonite for edible oil Production, IOP Conference Series: Materials Science and Engineering 1090 (2021) 012039. https://doi.org/10.1088/1757-899x/1090/1/012039 DOI: https://doi.org/10.1088/1757-899X/1090/1/012039
[49] Y. Bian, Y. Zhang, Z. Chen, L. Xu, C. Zhang, D. Shi, X. Feng, X. Wang, Malachite green in environ¬mental samples: Updates on sources, fates, distribution and removal techniques, Ecotoxi¬colo¬gy and Environmental Safety 303 (2025) 118978. https://doi.org/10.1016/j.ecoenv.2025.118978 DOI: https://doi.org/10.1016/j.ecoenv.2025.118978
[50] A. Yildirim, H. Acay, Methylene blue and malachite green dyes adsorption onto russula delica/bentonite/tripolyphosphate, Heliyon 11 (2025) e41250. https://doi.org/10.1016/j.heliyon.2024.e41250 DOI: https://doi.org/10.1016/j.heliyon.2024.e41250
[51] J. Song, L. Zhu, S. Yu, G. Li, D. Wang, The synergistic effect of adsorption and Fenton oxidation for organic pollutants in water remediation: an overview, RSC Advances 14 (2024) 33489-33511. https://doi.org/10.1039/D4RA03050H DOI: https://doi.org/10.1039/D4RA03050H
[52] M. Panizza, G. Cerisola, Electro-Fenton degradation of synthetic dyes, Water Research 43 (2009) 339-344. https://doi.org/10.1016/j.watres.2008.10.028 DOI: https://doi.org/10.1016/j.watres.2008.10.028
[53] Z. M. Hameed, R. H. Salman, Optimizing Methyl Orange Degradation via Electro-Fenton with Copper Foam Cathode: A Comparative Approach Using Iron Waste vs. Iron Salts and Exploring Catalyst and Cathode Durability, Applied Science and Engineering Progress 18 (2025) 7728. https://doi.org/10.14416/j.asep.2025.05.002 DOI: https://doi.org/10.14416/j.asep.2025.05.002
[54] N. Qiao, J. Chang, M. Hu, H. Ma, Novel bentonite particle electrodes based on Fenton catalyst and its application in Orange II removal, Desalination and Water Treatment 57 (2016) 17030-17038. https://doi.org/10.1080/19443994.2015.1083889 DOI: https://doi.org/10.1080/19443994.2015.1083889
[55] M. Fayazi, M. Ghanei-Motlagh, Electrochemical mineralization of methylene blue dye using electro-Fenton oxidation catalyzed by a novel sepiolite/pyrite nanocomposite, International Journal of Environmental Science and Technology 17 (2020) 4541-4548. https://doi.org/10.1007/s13762-020-02749-2 DOI: https://doi.org/10.1007/s13762-020-02749-2
Downloads
Published
Issue
Section
License
Copyright (c) 2026 Hind H. Thwaini, Zahraa M. Hameed, Rasha H. Salman
This work is licensed under a Creative Commons Attribution 4.0 International License.
