Tubular microreactor-based Fe(II)-driven advanced oxidation: comparative assessment of percarbonate and persulfate systems for toxic dye removal
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Slimane Merouani
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Leila Nemdili
Abstract
This study presents an intensified degradation strategy for azo dyes using a flow microreactor (6 m-length/1 mm-diameter)-integrated sulfate and hydroxyl radicals advanced oxidation processes (SO4 •−/•OH-AOPs) platform. Three systems were assessed: thermally activated persulfate (KPS), Fe(II)/KPS, and Fe(II)/sodium percarbonate (SPC), focusing on key parameters – bath temperature (20–70 °C), inlet dye concentration (5–20 µM), Fe(II) dosage (50–100 µM), pH (3–7), and oxidant flowrate (20–120 μL/s). Experiments were conducted with Basic Fuchsin (BF), a persistent dye of mutagenic and carcinogenic properties. Thermal KPS led to full dye conversion at 70 °C but negligible TOC removal at lower temperatures. Fe(II)/KPS and Fe(II)/SPC improved degradation across all temperatures. Fe(II)/KPS led to substantial mineralization (63 % TOC removal), while Fe(II)/SPC achieved only 33 %, and KPS alone 54 %. At 20 °C, Fe(II)/SPC showed slightly higher TOC removal than Fe(II)/KPS (18 % vs. 15 %). Performance was strongly influenced by Fe(II) speciation (pH-dependent) and radical scavenging by intermediates. Removal ratio analyses (Fe(II)/KPS to KPS: up to 5.0; Fe(II)/SPC to Fe(II)/KPS: up to 1.97) highlighted strong catalytic synergy, especially at low pH and low dye concentration. These findings demonstrate the potential of the microreactor-based SO4 •−/•OH-AOPs platform for scalable, energy-efficient, and high-throughput water treatment applications.
Acknowledgments
The authors gratefully acknowledge the financial support from the Ministry of Higher Education and Scientific Research of Algeria under project number A16N01UN250320220002, as well as the Directorate-General for Scientific Research and Technological Development (DGRSDT).
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Research ethics: Not applicable.
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Informed consent: All authors have given their consent for publication.
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Author contributions: Slimane Merouani: Investigation, conceptualizing, methodology, draft-writing and revising, and supervising the study. Leila Nemdili: Investigation. Marwa Derbal: Investigation. Aya E. Djidjekh: Investigation, Mostefa L. C. Benkara: Investigation.
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Use of Large Language Models, AI and Machine Learning Tools: AI tools were used solely for language enhancement purposes. Specifically, ChatGPT (OpenAI) was employed to improve the clarity, grammar, and flow of the English text. No content, data analysis, or scientific interpretation was generated by AI; all scientific content and conclusions are the original work of the authors.
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Conflict of interest: The authors declare no conflict of interest.
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Research funding: Not applicable.
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Data availability: Not applicable.
References
[1] P. S. Nishmitha, K. A. Akhilghosh, V. P. Aiswriya, A. Ramesh, M. Muthuchamy, and A. Muthukumar, “Understanding emerging contaminants in water and wastewater: a comprehensive review on detection, impacts, and solutions,” J. Hazard. Mater. Adv., vol. 18, no. 12, p. 100755, 2025, https://doi.org/10.1016/j.hazadv.2025.100755.Suche in Google Scholar
[2] K. H. Hama Aziz, F. S. Mustafa, K. M. Omer, and I. Shafiq, “Recent advances in water falling film reactor designs for the removal of organic pollutants by advanced oxidation processes: a review,” Water Resour. Ind., vol. 30, no. 22, p. 100227, 2023, https://doi.org/10.1016/j.wri.2023.100227.Suche in Google Scholar
[3] T. Krithiga et al.., “Persistent organic pollutants in water resources: fate, occurrence, characterization and risk analysis,” Sci. Total Environ., vol. 831, p. 154808, 2022, https://doi.org/10.1016/j.scitotenv.2022.154808.Suche in Google Scholar PubMed
[4] B. Lellis, C. Z. Fávaro-Polonio, J. A. Pamphile, and J. C. Polonio, “Effects of textile dyes on health and the environment and bioremediation potential of living organisms,” Biotechnol. Res. Innov., vol. 3, no. 2, pp. 275–290, 2019.10.1016/j.biori.2019.09.001Suche in Google Scholar
[5] R. Al-Tohamy et al.., “A critical review on the treatment of dye-containing wastewater: ecotoxicological and health concerns of textile dyes and possible remediation approaches for environmental safety,” Ecotoxicol. Environ. Saf., vol. 231, p. 113160, 2022, https://doi.org/10.1016/j.ecoenv.2021.113160.Suche in Google Scholar PubMed
[6] A. d. O. Martins, V. M. Canalli, C. M. N. Azevedo, and M. Pires, “Degradation of pararosaniline (C.I. basic red 9 monohydrochloride) dye by ozonation and sonolysis,” Dyes Pigm., vol. 68, nos. 2–3, pp. 227–234, 2006.10.1016/j.dyepig.2005.02.002Suche in Google Scholar
[7] M. E. M. Khalifa, C. Greff, and G. E. Raiulescu, “Use of triaminotriphenylamine as a reagent for the spectrophotometric determination of sulfur dioxide and nitrogen dioxide,” Anal. Lett., vol. 14, no. 4, pp. 249–259, 1981, https://doi.org/10.1080/00032718108081401.Suche in Google Scholar
[8] I. A. Schrijver, M.-J. Melief, M. van Meurs, A. R. Companjen, and J. D. Laman, “Pararosaniline fixation for detection of Co-stimulatory molecules, cytokines, and specific antibody,” J. Histochem. Cytochem., vol. 48, no. 1, pp. 95–103, 2000, https://doi.org/10.1177/002215540004800110.Suche in Google Scholar PubMed
[9] USA-DHH, “USA department of health and guman, toxicology and carcinogenesis studies of C.I. basic red 9 monohydrochloride (pararosaniline) (CAS No. 56961e9) in F344/N rats and B6C3F1 mice (feed studies),” Natl. Toxicol. Progr., Report Date: January 1986. Available at: https://ntp.niehs.ni.Suche in Google Scholar
[10] L. Wang, J. Wang, H. Pan, M. Zhao, and J. Chen, “Kinetics and removal pathwayof basic fuchsin by electrochemical oxidization,” J. Electroanal. Chem., vol. 880, p. 114792, 2021, https://doi.org/10.1016/j.jelechem.2020.114792.Suche in Google Scholar
[11] A. Taamallah, S. Merouani, and O. Hamdaoui, “Sonochemical degradation of basic fuchsin in water,” Desalin. Water Treat., vol. 57, no. 56, pp. 27314–27330, 2016, https://doi.org/10.1080/19443994.2016.1168320.Suche in Google Scholar
[12] M. Antonopoulou, E. Evgenidou, D. Lambropoulou, and I. Konstantinou, “A review on advanced oxidation processes for the removal of taste and odor compounds from aqueous media,” Water Res., vol. 53, pp. 215–234, 2014, https://doi.org/10.1016/j.watres.2014.01.028.Suche in Google Scholar PubMed
[13] M. I. Stefan, Advanced Oxidation Processes for Water Treatment: Fundamentals and Applications, London, IWA Publishing, 2017.10.2166/9781780407197Suche in Google Scholar
[14] A. Tsitonaki et al.., “In situ chemical oxidation of contaminated soil and groundwater using persulfate: a review,” Crit. Rev. Environ. Sci. Technol., vol. 40, no. 1, pp. 55–91, 2010, https://doi.org/10.1080/10643380802039303.Suche in Google Scholar
[15] H. Ren, Y. Quan, S. Liu, and J. Hao, “Effectiveness of ultrasound (US) and slightly acidic electrolyzed water (SAEW) treatments for removing listeria monocytogenes biofilms,” Ultrason. Sonochem., vol. 112, p. 107190, 2025, https://doi.org/10.1016/j.ultsonch.2024.107190.Suche in Google Scholar PubMed PubMed Central
[16] M. R. Samarghandi, J. Mehralipour, G. Azarian, K. Godini, and A. Shabanlo, “Decomposition of sodium dodecylbenzene sulfonate surfactant by electro/Fe2+-activated persulfate process from aqueous solutions,” Global Nest J., vol. 19, no. 1, pp. 115–121, 2017.10.30955/gnj.002063Suche in Google Scholar
[17] Q. Xie et al.., “Degradation of typical tetracycline antibiotics in landfill leachate by three-dimensional aerated electrocatalytic reactor (3D-AER): electrode properties, influencing factors and degradation mechanism,” J. Environ. Manage., vol. 386, p. 125787, 2025, https://doi.org/10.1016/j.jenvman.2025.125787.Suche in Google Scholar PubMed
[18] M. A. H. Karim and K. H. Hama Aziz, “Pristine almond-pomace derived biochar as a low-cost and sustainable peroxydisulfate activator for efficient removal of rhodamine B from water,” J. Water Process Eng., vol. 75, p. 108014, 2025, https://doi.org/10.1016/j.jwpe.2025.108014.Suche in Google Scholar
[19] S. Merouani, I. Bentama, D. Lekrine, I. Boumaiza, A. Dehane, and O. Hamdaoui, “Optimizing Fe(II)/chlorine-driven advanced textile dyes oxidation in a continuous stirred-tank reactor (CSTR): continuous-flow performance and role of Fe(IV) – oxo species,” Sep. Purif. Technol., vol. 376, p. 134116, 2025a, https://doi.org/10.1016/j.seppur.2025.134116.Suche in Google Scholar
[20] Merouani, S., A. Sigha, H. A. M. Hussein, and S. M. Y. Almajdalawi, “Continuous stirred tank reactor with recycled iron mixer for Fe(II)/chlorine-driven textile dyes oxidation: toward a sustainable continuous-flow process for micropollutants degradation,” J. Chem. Technol. Biotechnol., vol. 100, no. 10, pp. 2176–2186, 2025c, https://doi.org/10.1002/jctb.70031.Suche in Google Scholar
[21] S. Merouani, A. Sigha, H. A. M. Hussein, and S. M. Y. Almajdalawi, “Continuous stirred-tank degradation of persistent dyes via recycled iron/periodate oxidation system: process optimization,” J. Flow Chem., vol. 15, pp. 147–159, 2025d, https://doi.org/10.1007/s41981-025-00361-4.Suche in Google Scholar
[22] F. S. Mustafa and K. H. Hama Aziz, “Heterogeneous catalytic activation of persulfate for the removal of rhodamine B and diclofenac pollutants from water using iron-impregnated biochar derived from the waste of black seed pomace,” Process Saf. Environ. Prot., vol. 170, pp. 436–448, 2023, https://doi.org/10.1016/j.psep.2022.12.030.Suche in Google Scholar
[23] R. S. Dhamorikar, V. G. Lade, P. V. Kewalramani, and A. B. Bindwal, “Review on integrated advanced oxidation processes for water and wastewater treatment,” J. Ind. Eng. Chem., vol. 138, no. 1, pp. 104–122, 2024, https://doi.org/10.1016/j.jiec.2024.04.037.Suche in Google Scholar
[24] P. V. Nidheesh, C. Catia, V. K. Ansaf, and H. Nadais, “A review of integrated advanced oxidation processes and biological processes for organic pollutant removal,” Chem. Eng. Commun., vol. 209, no. 3, pp. 390–432, 2022.10.1080/00986445.2020.1864626Suche in Google Scholar
[25] S. Merouani, A. Dehane, A. Belghit, O. Hamdaoui, N. El Houda Boussalem, and H. Daif, “Removal of persistent textile dyes from wastewater by Fe(II)/H2O2/H3NOH+ integrated system: process performance and limitations,” Environ. Sci. Adv., vol. 1, no. 2, pp. 192–207, 2022, https://doi.org/10.1039/d2va00011c.Suche in Google Scholar
[26] S. Merouani et al.., “Protonated hydroxylamine-assisted iron catalytic activation of persulfate for the rapid removal of persistent organics from wastewater,” Clean: Soil, Air, Water, vol. 51, no. 3, p. 2100304, 2023, https://doi.org/10.1002/clen.202100304.Suche in Google Scholar
[27] C. Liang and H.-W. W. Su, “Identification of sulfate and hydroxyl radicals in thermally activated persulfate,” Ind. Eng. Chem. Res., vol. 48, no. 11, pp. 5558–5562, 2009, https://doi.org/10.1021/ie9002848.Suche in Google Scholar
[28] R. O. C. Norman, P. M. Storey, and P. R. West, “Electron spin resonance studies. Part XXV reaction of sulfate radical anions with organic compounds,” J. Chem. Soc. Sect. B Phys. Org., pp. 1087–1095, 1970. https://doi.org/10.1039/j29700001087.Suche in Google Scholar
[29] F. Z. Meghlaoui et al.., “Rapid catalytic degradation of refractory textile dyes in Fe (II)/chlorine system at near neutral pH: radical mechanism involving chlorine radical anion (Cl2•−)-mediated transformation pathways and impact of environmental matrices,” Sep. Purif. Technol., vol. 227, p. 115685, 2019.10.1016/j.seppur.2019.115685Suche in Google Scholar
[30] M. A. Oturan and J.-J. J. Aaron, “Advanced oxidation processes in water/wastewater treatment: principles and applications. A review,” Crit. Rev. Environ. Sci. Technol., vol. 44, no. 23, pp. 2577–2641, 2014, https://doi.org/10.1080/10643389.2013.829765.Suche in Google Scholar
[31] S. Merouani, O. Hamdaoui, and M. Bouhelassa, “Degradation of safranin O by thermally activated persulfate in the presence of mineral and organic additives: impact of environmental matrices,” Desalin. Water Treat., vol. 75, pp. 202–212, 2017, https://doi.org/10.5004/dwt.2017.20404.Suche in Google Scholar
[32] A. Talbi, S. Merouani, A. Dehane, H. Bouchoucha, A. Abdessemed, and M. S. O. Belahmadi, “Thermo-catalytic persulfate activation in tubular microreactors for advanced oxidation of safranin O: insights into process benefits and limitations,” Processes, vol. 13, no. 5, p. 1494, 2025b, https://doi.org/10.3390/pr13051494.Suche in Google Scholar
[33] Z. Boutamine et al.., “The investigation of the basic fuchsin dye photocatalytic degradation in aqueous media using stabilised span 80 and synthesized ultrasonically CuO nanoparticles (NPs),” React. Kinet. Mech. Catal., vol. 138, no. 3, pp. 1813–1832, 2025, https://doi.org/10.1007/s11144-025-02806-2.Suche in Google Scholar
[34] F. Khammar et al.., “Synthesis, characterization, and photocatalytic efficiency of Mg-doped ZnO nanoparticles for basic fuchsin dye degradation: experimental and theoretical insights,” Inorg. Chem. Commun., vol. 176, p. 114274, 2025, https://doi.org/10.1016/j.inoche.2025.114274.Suche in Google Scholar
[35] M. M. Kosanić and J. S. Tričković, “Degradation of pararosaniline dye photoassisted by visible light,” J. Photochem. Photobiol., A Chem., vol. 149, nos. 1–3, pp. 247–251, 2002.10.1016/S1010-6030(02)00007-2Suche in Google Scholar
[36] S. Merouani et al.., “Tubular microreactor-based Fe(II)/periodate degradation of persistent textile dyes: performance assessment , matrix evaluation and impact of ultrasound,” J. Water Process Eng., vol. 77, p. 108323, 2025b. https://doi.org/10.1016/j.jwpe.2025.108323.Suche in Google Scholar
[37] A. Talbi, S. Merouani, and A. Dehane, “Flowing microreactors for periodate/H2O2 advanced oxidative process: synergistic degradation and mineralization of organic dyes,” Processes, vol. 13, no. 5, p. 1487, 2025a, https://doi.org/10.3390/pr13051487.Suche in Google Scholar
[38] G. Dong et al.., “Advanced oxidation processes in microreactors for water and wastewater treatment: development, challenges, and opportunities,” Water Res., vol. 211, no. 34, p. 118047, 2022, https://doi.org/10.1016/j.watres.2022.118047.Suche in Google Scholar PubMed
[39] P. N. Nge, C. I. Rogers, and A. T. Woolley, “Advances in microfluidic materials, functions, integration, and applications,” Chem. Rev., vol. 113, no. 4, pp. 2550–2583, 2013, https://doi.org/10.1021/cr300337x.Suche in Google Scholar PubMed PubMed Central
[40] D. Cambié, C. Bottecchia, N. J. W. Straathof, V. Hessel, and T. Noël, “Applications of continuous-flow photochemistry in organic synthesis, material science, and water treatment,” Chem. Rev., vol. 116, no. 17, pp. 10276–10341, 2016, https://doi.org/10.1021/acs.chemrev.5b00707.Suche in Google Scholar PubMed
[41] J.-Y. Li, Z.-Q. Liu, Y.-H. Cui, S.-Q. Yang, J. Gu, and J. Ma, “Abatement of aromatic contaminants from wastewater by a heat/persulfate process based on a polymerization mechanism,” Environ. Sci. Technol., vol. 57, no. 47, pp. 18575–18585, 2023, https://doi.org/10.1021/acs.est.2c06137.Suche in Google Scholar PubMed
[42] N. E. Chadi, S. Merouani, O. Hamdaoui, M. Bouhelassa, and M. Ashokkumar, “H2O2/periodate (IO4−): a novel advanced oxidation technology for the degradation of refractory organic pollutants,” Environ. Sci. Water Res. Technol., vol. 5, no. 6, pp. 1113–1123, 2019, https://doi.org/10.1039/c9ew00147f.Suche in Google Scholar
[43] W. M. Wright and O. M. Reiff, “The thermal decomposition of hydrogen peorxyde,” J. Phys. Chem., vol. 31, no. 9, pp. 1352–1356, 1928, https://doi.org/10.1021/j150279a006.Suche in Google Scholar
[44] T. Xie et al.., “Dissolution factors and oxidative potential of acid soluble irons from chlorite mineral particles,” Atmos. Environ., vol. 255, nos. 1–4, p. 118436, 2021, https://doi.org/10.1016/j.atmosenv.2021.118436.Suche in Google Scholar
[45] J. J. Pignatello, E. Oliveros, and A. MacKay, “Advanced oxidation processes for organic contaminant destruction based on the fenton reaction and related chemistry,” Crit. Rev. Environ. Sci. Technol., vol. 36, no. 1, pp. 1–84, 2006, https://doi.org/10.1080/10643380500326564.Suche in Google Scholar
[46] A. Belghit, S. Merouani, and A. Dehane, “Exploring the intensifying effect of periodate/hydroxylamine oxidation process for the effective mineralization of textile dyes effluents with consideration of environmental matrices,” Asia-Pac. J. Chem. Eng., vol. 19, no. 1, pp. 1–16, 2024, https://doi.org/10.1002/apj.2981.Suche in Google Scholar
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