Malays. J. Anal. Sci. Volume 29 Number 6 (2025): 1633

Research Article

Catalytic activation of peroxymonosulfate with Mn and N co-doped carbon allotropes for alizarin yellow R degradation

Ganapaty Manickavasagam, Wen-Da Oh^*, and Mardiana Saaid

School of Chemical Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia

^*Corresponding author: ohwenda@usm.my

Received: 28 August 2025; Revised: 4 November 2025; Accepted: 15 November 2025; Published: 28 December 2025

Abstract

Transforming waste into catalysts for wastewater treatment embodies the circular economy concept and provides a sustainable approach to eliminate recalcitrant azo dyes. In this study, carbon nanotubes (CNTs) and biochar (BC) co-doped with Mn and N (i.e., Mn-N-CNT-1 and Mn-N-BC-1, respectively), along with their control forms (i.e., X, N-X, and Mn-X-1, X = CNT or BC), were synthesized via the pyrolysis method and systematically compared in terms of peroxymonosulfate (PMS) activation performance for alizarin yellow R (AYR) degradation, underlying mechanisms, stability, and phytotoxicity. X-ray diffraction (XRD) analysis revealed that Mn-N-CNT-1 exhibited a higher degree of graphitization than Mn-N-BC-1, while no crystalline Mn or Mn oxide phases were detected. Catalytic performance studies revealed that CNT co-doped with Mn and N possesses superior ability to degrade AYR (pseudo first-order rate constant (k_app) = 0.042 min^-1, 84.6 % removal) compared to controls and BC-based catalysts. Quenching experiments identified SO₄^•−, ¹O₂, and nonradical electron transfer as the dominant pathways for AYR degradation. Phytotoxicity assays confirmed that catalytic treatment reduced AYR toxicity, enabling normal seed germination and growth. In short, these findings in this study highlight CNT co-doped with Mn and N as efficient, reusable, and environmentally safe PMS activators for sustainable wastewater remediation.

Keywords: wastewater treatment, peroxymonosulfate activation, azo dye, biochar, carbon nanotubes

References

1. Li, Y., Zhang, D., Chen, Q., Chao, C., Sun, J., Dong, S., and Sun, Y. (2022). Synthesis of rGO/g-C₃N₄ for methyl orange degradation in activating peroxydisulfate under simulated solar light irradiation. Journal of Alloys and Compounds, 907, 164500.

2. Li, X., Zhang, J., Jiang, Y., Hu, M., Li, S., and Zhai, Q. (2013). Highly efficient biodecolorization/ degradation of Congo Red and Alizarin Yellow R by chloroperoxidase from Caldariomyces fumago: Catalytic mechanism and degradation pathway. Industrial and Engineering Chemistry Research, 52(38), 13572–13579.

3. Binh, N. T., Khue, D. N., Van Chung, T., Hoa, N. T., and Quang, D. S. (2019). Kinetic modeling of degradation for Alizarin Yellow R by activated persulfate using Fe⁰ (ZVI) under UV light. Vietnam Journal of Chemistry, 57(1), 46–51.

4. Ahmed, A., Usman, M., Yu, B., Ding, X., Peng, Q., Shen, Y., and Cong, H. (2020). Efficient photocatalytic degradation of toxic Alizarin Yellow R dye from industrial wastewater using biosynthesized Fe nanoparticles and study of factors affecting the degradation rate. Journal of Photochemistry and Photobiology B: Biology, 202, 111682.

5. Singh, G. B., Vinayak, A., Mudgal, G., and Kesari, K. K. (2024). Azo dye bioremediation: An interdisciplinary path to sustainable fashion. Environmental Technology and Innovation, 36, 103832.

6. Xiao, G., Xu, T., Faheem, M., Xi, Y., Zhou, T., Moryani, H. T., Bao, J., and Du, J. (2021). Evolution of singlet oxygen by activating peroxydisulfate and peroxymonosulfate: A review. International Journal of Environmental Research and Public Health, 18(7), 3344.

7. Li, H., Qin, X., Wang, K., Ma, T., and Shang, Y. (2024). Insight into metal-based catalysts for heterogeneous peroxymonosulfate activation: A critical review. Separation and Purification Technology, 333, 125900.

8. Brillas, E. (2024). Recent trends on the catalytic activation of peroxymonosulfate for the abatement of organic dyes in waters. Journal of Environmental Chemical Engineering, 12(4), 113191.

9. Xiao, S., Cheng, M., Zhong, H., Liu, Z., Liu, Y., Yang, X., and Liang, Q. (2020). Iron-mediated activation of persulfate and peroxymonosulfate in both homogeneous and heterogeneous ways: A review. Chemical Engineering Journal, 384, 123265.

10. Kohantorabi, M., Moussavi, G., and Giannakis, S. (2021). Innovations in metal- and carbon-based catalysts for heterogeneous peroxymonosulfate activation: Focus on radical versus nonradical degradation pathways. Chemical Engineering Journal, 411, 127957.

11. Huang, W., Xiao, S., Zhong, H., Yan, M., and Yang, X. (2021). Activation of persulfates by carbonaceous materials: A review. Chemical Engineering Journal, 418, 129297.

12. Pan, G., Wei, J., Xu, M., Li, J., Wang, L., Li, Y., Cui, N., Li, J., and Wang, Z. (2023). Insight into boron-doped biochar as an efficient metal-free catalyst for peroxymonosulfate activation: Role of –O–B–O– moieties. Journal of Hazardous Materials, 445, 130479.

13. He, L., Liao, G., Xie, Z., Liu, Y., and Yang, Y. (2025). Fe–N co-doped highly graphitized biochar for peroxymonosulfate activation toward degradation of persistent organic pollutants. Environmental Research, 286, 122786.

14. Huang, J., Zhu, Y., Bian, H., Song, L., Liu, Y., Lv, Y., Ye, X., Lin, C., and Li, X. (2023). Enhanced peroxydisulfate activation with B and Fe co-doped biochar from bark for rapid degradation of guaiacol. Molecules, 28(22), 7591.

15. Yang, X., Du, C., Chen, P., Zhang, S., Zhang, H., Xu, Q., and Zhuang, Z. (2025). Phosphorus-doped biochar loaded with cobalt nanoparticles for rapid acetaminophen degradation via peroxymonosulfate activation. Applied Surface Science, 713, 164309.

16. Huang, X., Yu, Z., Shi, Y., Liu, Q., and Fang, S. (2022). Highly efficient activation of peroxymonosulfate by Co,S co-doped bamboo biochar for sulfamethoxazole degradation. Journal of Environmental Chemical Engineering, 10(5), 108380.

17. Tao, Y., Sun, S., Hu, Y., Gong, S., Bao, S., Li, H., Zhang, X., Yuan, Z., and Wu, X. (2024). Activation of peroxymonosulfate by Fe,O co-embedded biochar for tetracycline degradation. Catalysts, 14(9), 556.

18. Sun, M., Fang, W., Liang, Q., Xing, Y., Lin, L., and Luo, H. (2024). Efficient acetaminophen degradation via peroxymonosulfate activation by Mn/N co-doped biochar. Journal of Environmental Chemical Engineering, 12(3), 112647.

19. Qu, G., Jia, P., Tang, S., Pervez, M. N., Pang, Y., Li, B., Cao, C., and Zhao, Y. (2024). Enhanced peroxymonosulfate activation via heteroatomic N-doping defects for BPA degradation. Journal of Hazardous Materials, 461, 132626.

20. Manickavasagam, G., He, C., Lin, K.-Y. A., Saaid, M., and Oh, W.-D. (2024). Advances and challenges of metal–heteroatom co-doped biochar as peroxymonosulfate activators. Environmental Research, 252, 118919.

21. Manickavasagam, G., He, C., Zhou, T., Hamidon, T. S., Hussin, M. H. H., Saaid, M., and Oh, W.-D. (2025). Stimulating catalytic activity of chars for norfloxacin removal via nitrogen and manganese functionalization. Separation and Purification Technology, 369, 133161.

22. Shende, R. C., Muruganathan, M., Mizuta, H., Akabori, M., and Sundara, R. (2018). Simultaneous synthesis of two nitrogen-rich carbon nanomaterials for all-solid-state symmetric supercapacitors. ACS Omega, 3(12), 17276–17286.

23. Shi, X., Huang, Z., Xu, J., Lin, S., Hong, Y., Zhang, Q., Xiao, J., and Hong, J. (2025). Co and N co-doped carbon nanotube catalysts for PMS activation. Separation and Purification Technology, 353, 128528.

24. Lim, X.-X., Low, S.-C., Tan, K. Q., Lin, K.-Y. A., Khoerunnisa, F., Lisak, G., and Oh, W.-D. (2024). Role of Ca in NiMoCa catalysts on carbon nanotube growth from face masks. Journal of Analytical and Applied Pyrolysis, 179, 106439.

25. Meng, H., Zhou, J., Nie, C., Li, W., Li, D., Zhang, Y., and Ao, Z. (2025). Mn-doped biochar induced peroxymonosulfate activation for phenol degradation. Journal of Hazardous Materials, 492, 138031.

26. Gasim, M. F., Veksha, A., Lisak, G., Low, S.-C. C., Hamidon, T. S., Hussin, M. H., and Oh, W.-D. (2023). Importance of carbon structure for N,S co-doping in ciprofloxacin removal. Journal of Colloid and Interface Science, 634, 586–600.

27. Fu, X., Li, Y., Cui, K., Liu, Y., and Lv, L. (2024). Mn and P co-doped biochar catalyst for persulfate degradation of tetracycline hydrochloride. Journal of Environmental Chemical Engineering, 12(6), 114228.

28. Manickavasagam, G., He, C., Zhou, T., Lin, K.-Y. A., Hamidon, T. S., Hussin, M. H., Saaid, M., and Oh, W.-D. (2024). Sustainable design of Co,N co-doped hydrochar as a PMS activator. Chemical Engineering Journal, 502, 157976.

29. Zhou, H., Kuang, Y., Gan, Y., Jiang, P., Pu, Y., and Yang, Y. (2025). Remediation of lead-contaminated soil using Fe–Mn–Ni layered double hydroxide biochar. Chemical Engineering Journal Advances, 100785.

30. Mutuma, M. K., Njogu, E. M., and Gichumbi, J. M. (2024). Synthesis and characterization of biochar–carbon nanotube composites for Rhodamine B adsorption. IOSR Journal of Applied Chemistry, 17(5): 27–42.

31. Jin, B., Wang, Q., Sainio, J., Saveleva, V. A., Jiang, H., Shi, J., Ali, B., Kallio, A.-J., Huotari, S., Sundholm, D., Han, N., and Kallio, T. (2024). Amorphous carbon-modulated quantum dot NiO for oxygen evolution. Applied Catalysis B: Environment and Energy, 358, 124437.

32. Chin, Y.-T., Manickavasagam, G., Lim, X.-X., Khoerunnisa, F., and Oh, W.-D. (2025). Biomass- and plastic-derived Co–N co-doped CNTs as PMS activators. Journal of Water Process Engineering, 72, 107635.

33. Zhang, M., Wen, Z., Zhang, L., Wang, Q., Zang, L., Feng, Q., Gu, Y., Wang, W., Ma, K., Zhang, H., Ji, D., Liu, J., Shi, X., and Yu, F. (2025). Radical and nonradical PMS activation by Fe₁₋ₓS/lignin biochar nanocomposites. Chemical Engineering Journal, 520, 166153.

34. Li, G., Cao, X., Meng, N., Huang, Y., Wang, X., Gao, Y., Li, X., Yang, T., Li, B., Zhang, Y., Lyu, X., and Liang, Y. (2022). Fe₃O₄-supported biochar for PMS activation in urea degradation. Chemical Engineering Journal, 433, 133595.

35. Jeong, W.-G., Kim, J.-G., Alshawabkeh, A. N., Larese-Casanova, P., Lim, J., and Baek, K. (2025). Electrochemical activation of PMS with biochar for p-nitrophenol removal. Journal of Water Process Engineering, 71, 107276.

36. Chen, X., Oh, W.-D., Hu, Z.-T., Sun, Y.-M., Webster, R. D., Li, S.-Z., and Lim, T.-T. (2018). Enhancing sulfacetamide degradation by PMS activation with N-doped graphene. Applied Catalysis B: Environmental, 225, 243–257.

37. Zhu, S., Huang, X., Ma, F., Wang, L., Duan, X., and Wang, S. (2018). Catalytic removal of aqueous contaminants on N-doped graphitic biochars. Environmental Science and Technology, 52(15), 8649–8658.

38. Xiao, Y., Mu, J., Peng, Q., Feng, J., Zhou, B., Zhang, N., and Liu, B. (2025). Oxygen-vacancy-enhanced PMS activation via carbon-hybrid defective Mn₂O₃. Journal of Environmental Chemical Engineering, 13(1), 115032.

39. Liu, T., Li, C., Chen, X., Chen, Y., Cui, K., Wang, D., and Wei, Q. (2024). PMS activation by Fe@N co-doped biochar for sulfamethoxazole degradation. International Journal of Molecular Sciences, 25(19), 10528.

40. Guo, L., Liu, D., Han, R., Yin, A., Gong, G., Li, S., Chen, R., Yang, J., Liu, Z., and Zhi, K. (2025). Advances in persulfate activation by carbon-based materials. Crystals, 15(5), 432.

41. Zhong, C., Zhang, S., Yang, S., Yuan, B., Xu, Q., Xie, Z., and Du, C. (2023). Mo,N co-doped iron biochar activating PMS for BPA degradation. Chemical Engineering Journal, 466, 143298.

42. Chen, W., Lei, L., Zhu, K., He, D., He, H., Li, X., Wang, Y., Huang, J., and Ai, Y. (2023). PMS activation by Fe–N–S co-doped carbocatalyst. Journal of Environmental Sciences, 129, 213–228.

43. Wu, Q., Zhang, Y., Meng, H., Wu, X., Liu, Y., and Li, L. (2024). Cu/N co-doped biochar activating PMS for selective paracetamol degradation. Chemosphere, 357, 141858.

44. Xue, Y., Kamali, M., Costa, M. E. V., Thompson, I. P., Huang, W., Rossi, B., Appels, L., and Dewil, R. (2024). PMS activation by Fe,N co-doped walnut shell biochar. Environmental Pollution, 355, 124018.

45. Kong, L., Zhu, M., and Zhan, J. (2025). Nitrogen-doped biochar aerogels as efficient PMS activators. Nanomaterials, 15(11), 865.

46. Huong, P. T., Jitae, K., Al Tahtamouni, T. M., Le Minh Tri, N., Kim, H.-H., Cho, K. H., and Lee, C. (2020). Biochar-derived PMS activation for oxidation of organic contaminants. Journal of Water Process Engineering, 33, 101037.

47. Yan, B., Li, Q., Chen, X., Deng, H., Feng, W., and Lu, H. (2022). O₃/PMS advanced oxidation technology for highly concentrated organic wastewater. Separations, 9(12), 444.

48. Wu, L., Lin, Y., Zhang, Y., Wang, P., Ding, M., Nie, M., Yan, C., and Chen, S. (2021). Ca(OH)₂-mediated PMS activation for bisphenol S degradation. RSC Advances, 11(53), 33626–33636.

49. Mashentseva, A. A., Aimanova, N. A., Parmanbek, N., Temirgaziyev, B. S., Barsbay, M., and Zdorovets, M. V. (2022). Plant-mediated synthesis of ZnO nanoparticles for Alizarin Yellow R removal. Nanomaterials, 12(19), 3293.

50. Neta, P., Huie, R. E., and 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.

51. Basu-Modak, S., and Tyrrell, R. M. (1993). Singlet oxygen: A primary effector in the ultraviolet A/near-visible light induction of the human heme oxygenase gene. Cancer Research, 53(19), 4505–4510.

52. Wang, J., Shen, M., Wang, H., Du, Y., Zhou, X., Liao, Z., Wang, H., and Chen, Z. (2020). Red mud-modified sludge biochar for the activation of peroxymonosulfate: Singlet oxygen-dominated mechanism and toxicity prediction. Science of the Total Environment, 740, 140388.

53. Wu, S., Liu, H., Yang, C., Li, X., Lin, Y., Yin, K., Sun, J., Teng, Q., Du, C., and Zhong, Y. (2020). High-performance porous carbon catalysts doped with iron and nitrogen for degradation of bisphenol F via peroxymonosulfate activation. Chemical Engineering Journal, 392, 123683.

54. Xu, L., Fu, B., Sun, Y., Jin, P., Bai, X., Jin, X., Shi, X., Wang, Y., and Nie, S. (2020). Degradation of organic pollutants by Fe/N co-doped biochar via peroxymonosulfate activation: Synthesis, performance, mechanism, and potential for practical application. Chemical Engineering Journal, 400, 125870.

55. Gan, Y., Zhu, K., Xia, W., Zhu, S., Tong, Z., Chen, W., Wang, Y., and Lin, B. (2022). Strongly coupled Fe/N co-doped graphitic carbon nanosheets/carbon nanotubes for rapid degradation of organic pollutants via peroxymonosulfate activation: Performance, mechanism, and degradation pathways. Separation and Purification Technology, 302, 122113.

56. Patil, D. S., Chavan, S. M., and Oubagaranadin, J. U. K. (2016). A review of technologies for manganese removal from wastewaters. Journal of Environmental Chemical Engineering, 4(1), 468–487.