In this study, heterogeneous catalytic ozonation using fl y ash (FA) modifi ed ZnO nanoparticles to the decolorization of acid

orange II (AOII) was studied. The combination of ZnO and fl y ash via an incipient wetness impregnation method to form

ZOFA composites created a synergistic eff ect that led to effi cient catalytic ozonation activity towards AOII degradation

and decolorization compared with individual ozonation processes. From the experimental results, ZOFA composite with

the optimal weight ratio between ZnO NPs and FA was 20 wt% (denoted as ZOFA-20) that exhibited outstanding catalytic

ozonation activity. Moreover, through other investigations including initial pH conditions and catalyst dosage, AOII could

be eff ectively and optimally eliminated by 0.5 g of ZOFA-20 with an initial pH value of 11. The corresponding k value was

measured as 0.248 min −1 with a maximum TOC removal content of 77.27%. Besides, ZOFA-20 could show high catalytic

ozonation activity even at highly concentrated AOII concentrations while it could also retain its excellent stability and reusability

over 5 continuous AOII removal cycles. From the experimental and electron paramagnetic resonance (EPR) results,

hydroxyl radical ( · OH) was the main active species during the catalytic ozonation of AOII. The present study provides a

promising approach to prepare novel composite-based fl y ash that would be applicable for removing azo dye and other dye

pollutants in water via a catalytic ozonation strategy.

Acid orange II · Azo dye · Catalytic ozonation · Fly ash · ZnO · · OH

1. A. Özcan, M.A. Oturan, N. Oturan, Y. Şahin, J. Hazard. Mater.
163 , 1213 (2009)
2. A.B. Dos Santos, F.J. Cervantes, J.B. van Lier, Bioresour. Technol.
98 , 2369 (2007)
3. M.M. Hassan, C.M. Carr, Chemosphere 209 , 201 (2018)
4. Y. Zhou, J. Lu, Y. Zhou, Y. Liu, Environ. Pollut. 252 , 352 (2019)
5. H. J. Perera, in 2020 Adv. Sci. Eng. Technol. Int. Conf. (2020), pp.
1–6.
6. G.S. Heiss, B. Gowan, E.R. Dabbs, FEMS Microbiol. Lett. 99 ,
221 (1992)
7. S. Garcia-Segura, S. Dosta, J.M. Guilemany, E. Brillas, Appl.
Catal. B 132–133 , 142 (2013)
8. G. Qu, H. Wang, X. Li, T. Wang, Z. Zhang, D. Liang, H. Qiang,
Water Sci. Technol. 83 , 257 (2020)
9. H. Xiong, B. Zhang, C. Cui, Y. Xu, Mater. Chem. Phys. 278 ,
125701 (2022)
10. L. Zhang, Z. Cheng, X. Guo, X. Jiang, R. Liu, J. Mol. Liq. 197 ,
353 (2014)
11. K. Lin, S. Afzal, L. Xu, T. Ding, F. Li, M. Zhang, Environ. Pollut.
327 , 121454 (2023)
12. N. Nasseh, F.S. Arghavan, S. Rodriguez-Couto, A. HosseinPanahi,
M. Esmati, T.J. A-Musawi, Adv. Powder Technol. 31 , 875 (2020)
13. B. Naraghi, F. Zabihi, M.R. Narooie, M. Saeidi, H. Biglari, Electron.
Phys. 9 , 4312 (2017)
14. Y. Du, M. Dai, J. Cao, C. Peng, I. Ali, I. Naz, J. Li, Chemosphere
244 , 125522 (2020)
15. C.V. Rekhate, J.K. Srivastava, Chem. Eng. J. Adv. 3 , 100031
(2020)
16. F. Huang, H. Wang, X. Ruan, Water Environ. Res. 94 , e10796
(2022)
17. X. Wang, X. Hu, C. Zhao, Z. Sun, H. Zheng, J. Li, Z. Wang, Water
Sci. Technol. 79 , 1195 (2019)
18. K. Guan, P. Zhou, J. Zhang, L. Zhu, Mater. Res. Express 7 , 16529
(2020)
19. H. Lin, H. Zhang, L. Hou, J. Hazard. Mater. 276 , 182 (2014)
20. J. Wang, H. Chen, Sci. Total. Environ. 704 , 135249 (2020)
21. F.J. Beltrán, J. Rivas, P. Álvarez, R. Montero-de-Espinosa, Ozone
Sci. Eng. 24 , 227 (2002)
22. J. Nawrocki, B. Kasprzyk-Hordern, Appl. Catal. B 99 , 27 (2010)
23. W.-L. Wang, H.-Y. Hu, X. Liu, H.-X. Shi, T.-H. Zhou, C. Wang,
Z.-Y. Huo, Q.-Y. Wu, Chemosphere 231 , 369 (2019)
24. P. Li, R. Miao, P. Wang, F. Sun, X. Li, Chem. Eng. J. 426 , 131263
(2021)
25. S. Maddila, V.D.B.C. Dasireddy, S.B. Jonnalagadda, Appl. Catal.
B 138–139 , 149 (2013)
26. L. Zhou, S. Zhang, Z. Li, X. Liang, Z. Zhang, R. Liu, J. Yun, J.
Water Process Eng. 36 , 101168 (2020)
27. J. Wang, X. Quan, S. Chen, H. Yu, G. Liu, J. Hazard. Mater. 368 ,
621 (2019)
28. Z. Yang, H. Yang, Y. Liu, C. Hu, H. Jing, H. Li, Ozone Sci. Eng.
45 , 147 (2023)
29. Z. Hussain, G. Lizhen, M. Moeen, Sustainability 12 , 5218 (2020)
30. M. Zhang, Y. Mao, W. Wang, S. Yang, Z. Song, X. Zhao, RSC
Adv. 6 , 93564 (2016)
31. C. Rodwihok, M. Suwannakaew, S.W. Han, Y.J. Lim, S.Y. Park,
S.W. Woo, J.W. Choe, D. Wongratanaphisan, H.S. Kim, Colloids
Surf. A 662 , 131044 (2023)
32. K. He, C. Zhao, G. Zhao, G. Han, J. Sol-Gel Sci. Technol. 75 , 557
(2015)
33. J.-L. Blin, A. Léonard, Z.-Y. Yuan, L. Gigot, A. Vantomme, A.K.
Cheetham, B.-L. Su, Angew. Chemie 115 , 2978 (2003)
34. H. Valdés, M. Sánchez-Polo, J. Rivera-Utrilla, C.A. Zaror, Langmuir
18 , 2111 (2002)
35. M. Szekeres, J. Tóth, I. Dékány, Langmuir 18 , 2678 (2002)
36. C. Rodwihok, M. Suwannakeaw, K. Charoensri, D. Wongratanaphisan,
S. Woon Woo, H.S. Kim, Bioresour. Technol. 331 , 125060
(2021)
37. H. Zhu, W. Ma, H. Han, Y. Han, W. Ma, Chem. Eng. J. 327 , 91
(2017)
38. L. Zhao, Z. Sun, J. Ma, Environ. Sci. Technol. 43 , 4157 (2009)
39. A. Łamacz, K. Matus, B. Liszka, J. Silvestre-Albero, M. Lafj ah,
T. Dintzer, I. Janowska, Catal. Today 301 , 172 (2018)
40. M. Babar, H.M.S. Munir, A. Nawaz, N. Ramzan, U. Azhar, M.
Sagir, M.S. Tahir, A. Ikhlaq, S.N. huda Mohammad Azmin, M.
Mubashir, K.S. Khoo, K.W. Chew, Chemosphere 307 , 135738
(2022)
41. S.P. Ghuge, A.K. Saroha, Process. Saf. Environ. Prot. 118 , 125
(2018)
42. J. Bing, C. Hu, Y. Nie, M. Yang, J. Qu, Environ. Sci. Technol. 49 ,
1690 (2015)
43. G. Yu, Y. Wang, H. Cao, H. Zhao, Y. Xie, Environ. Sci. Technol.
54 , 5931 (2020)