The iron-based biochar activating chlorite (ClO₂⁻) driven by mechanochemical ultrasonic: piecewise kinetics, biomimetic catalytic-mechanism, and novel advanced redox process

Abstract

Chlorite (ClO₂⁻ or COI) is used to establish the advanced reduction and oxidation process (AROP). The iron/biochar-based particles (iron-based hydrothermal carbon with hinge-like structure, Fe_bHCs, 20 mg/L) can be utilized to activate COI (2 mmol/L) to present selective oxidation in removing triphenylmethane derivatives (15 min, 90%). The protonation (H⁺ at ~10² μmol/L level) played a huge role (k-2^nd = 0.136c-H⁺ − 0.014 (R²-adj = 0.986), and r_app = − 0.0876/c-H⁺ + 1.017 (R²-adj = 0.996)) to boost the generation of the active species (e.g., high-valent iron oxidizing species (HVI=O) and chlorine dioxide (ClO₂)). The protonation-coupled electron transfer promoted Fe-substances in Fe_b/HCs activating COI (the calculated k_obs ranging from 0.066−0.285 min⁻¹). The form of ClO₂ mainly attributed to proton-coupled electron transfer (1e/1H⁺). The HVI=O was generated from the electron transfer within the coordination complex. Moreover, carbon particles in Fe_bHCs serve as the bridge for electron transfer. The above roles contribute to the fracture and formation of coordination-induced bonds between L_x-Fe^II/III and ClO₂⁻ at phase interface to form AROP. The ultrasonic (US) cavitation enhanced the mass transfer of active species in bulk solution, and the HVI=O and ClO₂ attack unsaturated central carbon atoms of triphenylmethane derivatives to initiate selective removal. Furthermore, the scale-up experiment with continuous flow (k values of approximately 0.2 min⁻¹, COD removal efficiency of approximately 80%) and the reactor with COMSOL simulation have also proved the applicability of the system. The study offers a novel AROP and new insights into correspondingly heterogeneous interface activation mechanisms.

Graphical abstract

Keywords

Chlorite / Iron-based biochar / Ultrasonic / Chlorine dioxide / High-valent iron oxidizing species

Highlight

	● A novel process of sonocatalysis/iron-carbon particles activating ClO2− was provided.
	● Activation mechanism of ClO2− attributed to the protonation coupled electron transfer.
	● Dominant active species involved high-valent iron oxidizing species and ClO2.
	● Ultrasonic played the roles of “carrying” and “driving” forces.

References

[1] Bulman D M, Mezyk S P, Remucal C K. (2019). The impact of pH and irradiation wavelength on the production of reactive oxidants during chlorine photolysis. Environmental Science & Technology, 53(8): 4450–4459

[2] Chen L, Duan J, Du P H, Sun W L, Lai B, Liu W. (2022). Accurate identification of radicals by in-situ electron paramagnetic resonance in ultraviolet-based homogenous advanced oxidation processes. Water Research, 221: 118747

[3] Chen W R, He H X, Liang J T, Wei X P, Li X K, Wang J, Li L S. (2023). A comprehensive review on metal based active sites and their interaction with O₃ during heterogeneous catalytic ozonation process: types, regulation and authentication. Journal of Hazardous Materials, 443: 130302

[4] Cheng C, Ren W, Miao F, Chen X T, Chen X X, Zhang H. (2023). Generation of Fe^IV=O and its contribution to Fenton-like reactions on a single-atom iron-N-C catalyst. Angewandte Chemie International Edition, 62(10): e202218510

[5] Choi J, Cui M, Lee Y, Ma J, Kim J, Son Y, Khim J. (2019). Hybrid reactor based on hydrodynamic cavitation, ozonation, and persulfate oxidation for oxalic acid decomposition during rare-earth extraction processes. Ultrasonics Sonochemistry, 52: 326–335

[6] Deng G W, Wang Z, Ma J X, Jiang J, He D, Li X H, Szczuka A, Zhang Z. (2023). Ferryl ion in the photo-Fenton process at acidic pH: occurrence, fate, and implications. Environmental Science & Technology, 57(47): 18586–18596

[7] Duan X G, Sun H Q, Wang S. (2018). Metal-free carbocatalysis in advanced oxidation reactions. Accounts of Chemical Research, 51(3): 678–687

[8] Fu X J, Zeng Q M, Song L, Wu Y Y, Wang R Z, Zeng Q Y. (2024a). Insight into the performance and mechanism of N,O,S-codoped porous carbon based CO single-atom catalysts in organic oxidation through peroxymonosulfate activation. Chemical Engineering Journal, 497: 154668

[9] Fu X J, Zeng Q M, Gao Y W, Song L, Wen Y J, Cai T, Zhang Q S, Hu C, Zeng Q Y. (2024b). Single-atom Mn–N₄ catalyst with electron-rich O and S self-doping for cooperative nonradical and radical oxidation: overlooked nonmetal heteroatomic sites. ACS ES&T Engineering, 4(4): 903–914

[10] Gan W H, Ge Y X, Zhong Y, Yang X. (2020). The reactions of chlorine dioxide with inorganic and organic compounds in water treatment: kinetics and mechanisms. Environmental Science. Water Research & Technology, 6(9): 2287–2312

[11] GB5749−2022 (2022). Standards for Drinking Water Quality. Beijing: National Standard of the People’s Republic of China

[12] Guan C T, Jiang J, Pang S Y, Luo C W, Ma J, Zhou Y, Yang Y. (2017). Oxidation kinetics of bromophenols by nonradical activation of peroxydisulfate in the presence of carbon nanotube and formation of brominated polymeric products. Environmental Science & Technology, 51(18): 10718–10728

[13] Hao R L, Mao X Z, Qian Z, Zhao Y, Wang L D, Yuan B, Wang K M, Liu Z H, Qi M, Crittenden J. (2019a). Simultaneous removal of SO₂ and NO using a novel method of ultraviolet irradiating chlorite–ammonia complex. Environmental Science & Technology, 53(15): 9014–9023

[14] Hao R L, Wang Z, Mao X Z, Gong Y P, Yuan B, Zhao Y, Tian B J, Qi M. (2019b). Elemental mercury removal by a novel advanced oxidation process of ultraviolet/chlorite-ammonia: mechanism and kinetics. Journal of Hazardous Materials, 374: 120–128

[15] Hicks S D, Kim D, Xiong S L, Medvedev G A, Caruthers J, Hong S, Nam W, Abu-Omar M M. (2014). Non-heme manganese catalysts for on-demand production of chlorine dioxide in water and under mild conditions. Journal of the American Chemical Society, 136(9): 3680–3686

[16] Lee A Q, Streit B R, Zdilla M J, Abu-Omar M M, DuBois J. (2008). Mechanism of and exquisite selectivity for O-O bond formation by the heme-dependent chlorite dismutase. Proceedings of the National Academy of Sciences of the United States of America, 105(41): 15654–15659

[17] Lee J, von Gunten U, Kim J H. (2020). Persulfate-based advanced oxidation: critical assessment of opportunities and roadblocks. Environmental Science & Technology, 54(6): 3064–3081

[18] Lei Y, Yu Y F, Lei X, Liang X, Cheng S S, Ouyang G F, Yang X. (2023). Assessing the use of probes and quenchers for understanding the reactive species in advanced oxidation processes. Environmental Science & Technology, 57(13): 5433–5444

[19] Li N, Ye J Y, Dai H X, Shao P H, Liang L, Kong L C, Yan B B, Chen G Y, Duan X G. (2023). A critical review on correlating active sites, oxidative species and degradation routes with persulfate-based antibiotics oxidation. Water Research, 235: 119926

[20] Liu B H, Guo W Q, Jia W R, Wang H Z, Si Q S, Zhao Q, Luo H C, Jiang J, Ren N Q. (2021). Novel nonradical oxidation of sulfonamide antibiotics with Co(II)-doped g-C₃N₄-activated peracetic acid: role of high-valent cobalt−oxo species. Environmental Science & Technology, 55(18): 12640–12651

[21] Liu W Y, Fu P B, Zhang Y Y, Xu H, Wang H L, Xing M Y. (2023). Efficient hydrogen production from wastewater remediation by piezoelectricity coupling advanced oxidation processes. Proceedings of the National Academy of Sciences of the United States of America, 120(7): e2218813120

[22] Lu S H, Shang C, Sun B, Xiang Y Y. (2023). Dominant dissolved oxygen-independent pathway to form hydroxyl radicals and the generation of reactive chlorine and nitrogen species in breakpoint chlorination. Environmental Science & Technology, 57(1): 150–159

[23] Ma D M, Yang Y, Liu B F, Xie G J, Chen C, Ren N Q, Xing D F. (2021). Zero-valent iron and biochar composite with high specific surface area via K₂FeO₄ fabrication enhances sulfadiazine removal by persulfate activation. Chemical Engineering Journal, 408: 127992

[24] Mayer J M. (2023). Bonds over electrons: proton coupled electron transfer at solid−solution interfaces. Journal of the American Chemical Society, 145(13): 7050–7064

[25] Miklos D B, Remy C, Jekel M, Linden K G, Drewes J E, Hübner U. (2018). Evaluation of advanced oxidation processes for water and wastewater treatment: a critical review. Water Research, 139: 118–131

[26] IARC Monographs Vol 129 group. (2022). Carcinogenicity of gentian violet, leucogentian violet, malachite green, leucomalachite green, and CI Direct Blue 218. Lancet. Oncology, 22: 585–586

[27] Neta P, Huie R E, Ross A B. (1988). Rate constants for reactions of inorganic radicals in aqueous solution. Journal of Physical and Chemical Reference Data, 17(3): 1027–1284

[28] Pignatello J J, Oliveros E, Mackay A. (2006). Advanced oxidation processes for organic contaminant destruction based on the Fenton reaction and related chemistry. Critical Reviews in Environmental Science and Technology, 36(1): 1–84

[29] Pona A, Quan E Y, Cline A, Feldman S R. (2020). Review of the use of gentian violet in dermatology practice. Dermatology Online Journal, 26(5): 1

[30] Ren C X, Bi E Y, Gao J Y, Liu J Y. (2022a). Molybdenum-catalyzed perchlorate reduction: robustness, challenges, and solutions. ACS ES&T Engineering, 2(2): 181–188

[31] Ren W, Cheng C, Shao P H, Luo X B, Zhang H, Wang S B, Duan X G. (2022b). Origins of electron-transfer regime in persulfate-based nonradical oxidation processes. Environmental Science & Technology, 56(1): 78–97

[32] Ren C X, Yang P, Sun J N, Bi E Y, Gao J Y, Palmer J, Zhu M Q, Wu Y Y, Liu J Y. (2021). A bioinspired molybdenum catalyst for aqueous perchlorate reduction. Journal of the American Chemical Society, 143(21): 7891–7896

[33] Ren W, Nie G, Zhou P, Zhang H, Duan X G, Wang S B. (2020). The intrinsic nature of persulfate activation and N-doping in carbocatalysis. Environmental Science & Technology, 54(10): 6438–6447

[34] Song J S, Hou N N, Liu X C, Antonietti M, Zhang P J, Ding R R, Song L, Wang Y, Mu Y. (2023). Asymmetrically coordinated CoB₁N₃ moieties for selective generation of high-valence Co-oxo species via coupled electron–proton transfer in Fenton-like reactions. Advanced Materials, 35(23): 2209552

[35] Song X Y, Su R D, Wang Y H, Zhang Y, Gao B Y, Wang Y, Ma D F, Li Q. (2023). Visible light-driven chlorite activation process for enhanced sulfamethoxazole antibiotics degradation, antimicrobial resistance reduction and biotoxicity elimination. Chemical Engineering Journal, 452: 139103

[36] Su R D, He M X, Li N, Ma D F, Zhou W Z, Gao B Y, Yue Q Y, Li Q. (2022). Visible-light photocatalytic chlorite activation mediated by oxygen vacancy abundant Nd-doped BiVO₄ for efficient chlorine dioxide generation and pollutant degradation. ACS Applied Materials & Interfaces, 14(28): 31920–31932

[37] Su R D, Huang L, Li N, Li L, Jin B, Zhou W Z, Gao B Y, Yue Q Y, Li Q. (2021). Chlorine dioxide radicals triggered by chlorite under visible-light irradiation for enhanced degradation and detoxification of norfloxacin antibiotic: radical mechanism and toxicity evaluation. Chemical Engineering Journal, 414: 128768

[38] Su R D, Li N, Liu Z, Song X Y, Liu W, Gao B Y, Zhou W Z, Yue Q Y, Li Q. (2023). Revealing the generation of high-valent cobalt species and chlorine dioxide in the Co₃O₄-activated chlorite process: insight into the proton enhancement effect. Environmental Science & Technology, 57(5): 1882–1893

[39] Tyburski R, Liu T F, Glover S D, Hammarström L. (2021). Proton-coupled electron transfer guidelines, fair and square. Journal of the American Chemical Society, 143(2): 560–576

[40] Wang J E, Wu Y T, Bu L J, Zhu S M, Zhang W Q, Zhou S Q, Gao N Y. (2021). Simultaneous removal of chlorite and contaminants of emerging concern under UV photolysis: hydroxyl radicals vs. chlorate formation. Water Research, 190: 116708

[41] Wang J L, Wang S Z. (2018). Activation of persulfate (PS) and peroxymonosulfate (PMS) and application for the degradation of emerging contaminants. Chemical Engineering Journal, 334: 1502–1517

[42] Wang Z, Qiu W, Pang S Y, Guo Q, Guan C T, Jiang J. (2022). Aqueous iron(IV)-oxo complex: an emerging powerful reactive oxidant formed by iron(II)-based advanced oxidation processes for oxidative water treatment. Environmental Science & Technology, 56(3): 1492–1509

[43] Wang Z, Zhang W J, Wang Z W, Chang J. (2023). Ozonation of aromatic monomer compounds in water: factors determining reaction outcomes. Frontiers of Environmental Science & Engineering, 17(5): 54

[44] World Water Assessment Programme (WWAP) (2015). The United Nations World Water Development Report 2015: Water for a Sustainable World, Facts and Figures; UN Water Rep

[45] Wu J H, Chen F, Yang T H, Yu H Q. (2023). Unveiling singlet oxygen spin trapping in catalytic oxidation processes using in situ kinetic EPR analysis. Proceedings of the National Academy of Sciences of the United States of America, 120(30): e2305706120

[46] Xiao X, Chen C, Deng J W, Wu J H, He K L, Xiang Z M, Yang Y Y. (2020). Analysis of trace malachite green, crystal violet, and their metabolites in zebrafish by surface-coated probe nanoelectrospray ionization mass spectrometry. Talanta, 217: 121064

[47] Xu J G, Wang D, Hu D, Zhang Z W, Chen J H, Wang Y M, Zhang Y F. (2024). Magnetic Co-doped 1D/2D structured γ-Fe₂O₃/MoS₂ effectively activated peroxymonosulfate for efficient abatement of bisphenol A via both radical and non-radical pathways. Frontiers of Environmental Science & Engineering, 18(3): 37

[48] Xu Q H, Leng H R, You H, Wang S T, Li H Y, Yu Y B. (2022a). A novel co-catalyzed system between persulfate and chlorite by sonolysis for removing triphenylmethane derivative. Journal of Environmental Sciences, 112: 291–306

[49] Xu Q H, Li Z P, You H, Wang S T, Li H Y. (2022b). Magnetically separable Fe-base deposited on different carbon sources for ultrasound/persulfate-like heterogeneous activation: optimized synthesis and field driving process. Chemosphere, 298: 134270

[50] Xu Y, Guo Q, Li Y, Qin L J, Zhang K G, Liu G R, Yuan C G. (2022c). Stabilization of nano zero-valent iron by electrospun composite mat with good catalysis and recyclability. Journal of Cleaner Production, 363: 132459

[51] Xu Q H, Li Z P, Liu F, You H, Xie B H. (2023). Iron species activating chlorite: neglected selective oxidation for water treatment. Environmental Science and Ecotechnology, 14: 100225

[52] Xu Q H, Yang Q H, Luo R, Fei Z H, You H. (2025). Nonmetallic nitrogen doped hydrothermal carbon driven by ultrasonic mechanochemical action for activating (mono- and dual-) persulfate: comparison of activation performance and reaction mechanism. Separation and Purification Technology, 354: 128770

[53] Yamashita T, Hayes P. (2008). Analysis of XPS spectra of Fe²⁺ and Fe³⁺ ions in oxide materials. Applied Surface Science, 254: 2441–2449

[54] Yang T, Zhu M Y, An L Q, Zeng G, Fan C Q, Li J, Jiang J, Ma J. (2023). Photolysis of chlorite by solar light: an overlooked mitigation pathway for chlorite and micropollutants. Water Research, 233: 119809

[55] Yao J, Wu N, Tang X S, Wang Z Y, Qu R J, Huo Z L. (2022). Methyl phenyl sulfoxide (PMSO) as a quenching agent for high-valent metal-oxo species in peroxymonosulfate based processes should be reconsidered. Chemical Engineering Journal Advances, 12: 100378

[56] Ye W K, Tian F X, Chen C, Ye J, Liu F W, Wang B, Hu X J, Xu B. (2023). Performance evaluation of the UV activated chlorite process on trimethoprim: degradation efficiency, energy consumption and disinfection by-products formation. Chemosphere, 327: 138540

[57] Yu J F, Tang L, Pang Y, Liang X M, Lu Y, Feng H P, Wang J J, Deng L F, Zou J J, Zhu X. . (2022). Non-radical oxidation in environmental catalysis: recognition, identification, and perspectives. Chemical Engineering Journal, 433: 134385

[58] Zdilla M J, Lee A Q, Abu-Omar M M. (2008). Bioinspired dismutation of chlorite to dioxygen and chloride catalyzed by a water-soluble iron porphyrin. Angewandte Chemie International Edition, 47(40): 7697–7700

[59] Zhang Y J, Huang G X, Winter L R, Chen J J, Tian L L, Mei S C, Zhang Z, Chen F, Guo Z Y, Ji R. . (2022). Simultaneous nanocatalytic surface activation of pollutants and oxidants for highly efficient water Decontamination. Nature Communications, 13(1): 3005

[60] Zhao G Q, Zou J, Chen X Q, Liu L K, Wang Y K, Zhou S, Long X Q, Yu J G, Jiao F P. (2021). Iron-based catalysts for persulfate-based advanced oxidation process: microstructure, property and tailoring. Chemical Engineering Journal, 421: 127845

RIGHTS & PERMISSIONS

Higher Education Press 2025