Enhanced Photocatalytic Degradation of Methyl Red Dye Via Hydrothermally Synthesized Manganese Tungstate

Abstract

In this study, MnWO₄ nanoparticles were successfully synthesized via a CTAB-assisted hydrothermal method and evaluated for their photocatalytic degradation performance against Methyl Red (MR) dye under UV-C irradiation. Structural and morphological characterizations were performed using XRD, FTIR, SEM, and UV-DRS techniques, confirming the formation of highly crystalline monoclinic MnWO₄ with defect-rich surfaces. The photocatalytic experiments were conducted under UV-C light (254 nm) with a catalyst dosage of 0.5 g/L, initial MR concentration of 20 mg/L, and solution pH of 6.5. The synthesized MnWO₄ exhibited excellent degradation efficiency, achieving 98% MR removal within 90 minutes, outperforming several conventional photocatalysts. This work addresses a critical gap in the literature by demonstrating the enhanced activity of CTAB-modified MnWO₄ under UV-C light, offering a promising route for azo dye remediation. The findings suggest that morphology control and surface defect engineering significantly influence photocatalytic performance, making MnWO₄ a viable candidate for environmental applications.

Keywords

• Manganese tungstate
• Hydrothermal synthesis
• Methyl red
• UV-C photocatalysis
• Azo dye degradation
• Band gap engineering

References

1. Ahmad MA, Ahmad N, Bello OS. 2015. Modified durian seed as adsorbent for the removal of methyl red dye from aqueous solutions. Appl Water Sci, 5(4): 407–423. https://doi.org/10.1007/s13201-014-0208-4
2. Ahmad MA, Ahmed NB, Adegoke KA, Bello OS. 2019. Sorption studies of methyl red dye removal using lemon grass (Cymbopogon citratus). Chem Data Collect, 22: 100249. https://doi.org/10.1016/j.cdc.2019.100249
3. Alharbi AA, Aldaghri O, El-Badry BA, Ibnaouf KH, Alfadhl F, Albadri A, Modwi A. 2024. Degradation of methyl red dye via fabricated Y₂O₃–MgO/g-C₃N₄ nanostructures: modification of band gap and photocatalysis under visible light. Opt Mater, 152: 115443. https://doi.org/10.1016/j.optmat.2024.115443
4. Allabakshi SM, Srikar PSNSR, Gangwar RK, Maliyekkal SM. 2025. Nonthermal plasma technology for degradation of dyes in wastewater. In: Hamdaoui O (Ed.), Innovative and Hybrid Advanced Oxidation Processes for Water Treatment. Elsevier, pp: 255–278. https://doi.org/10.1016/B978-0-443-14100-3.00001-6
5. Almeida MAP, Cavalcante LS, Varela JA, Li MS, Longo E. 2012. Effect of different surfactants on the shape, growth and photoluminescence behavior of MnWO₄ crystals synthesized by the microwave-hydrothermal method. Adv Powder Technol, 23(1): 124–128. https://doi.org/10.1016/j.apt.2011.10.004
6. Berradi M, Hsissou R, Khudhair M, Assouag M, Cherkaoui O, El Bachiri A, El Harfi A. 2019. Textile finishing dyes and their impact on aquatic environs. Heliyon, 5(11): e02711. https://doi.org/10.1016/j.heliyon.2019.e02711
7. Chakraborty AK, Ganguli S, Kebede MA. 2012. Photocatalytic degradation of 2-propanol and phenol using Au loaded MnWO₄ nanorod under visible light irradiation. J Cluster Sci, 23(2): 437–448. https://doi.org/10.1007/s10876-012-0450-6
8. Gaim YT, Tesfamariam GM, Nigussie GY, Ashebir ME. 2019. Synthesis, characterization and photocatalytic activity of N-doped Cu₂O/ZnO nanocomposite on degradation of methyl red. J Compos Sci, 3(4): 93. https://doi.org/10.3390/jcs3040093

9. Grass RN, Tsantilis S, Pratsinis SE. 2006. Design of high-temperature, gas-phase synthesis of hard or soft TiO₂ agglomerates. AIChE J, 52(4): 1318–1325. https://doi.org/10.1002/aic.10739
10. Hassan MS, Amna T, Al-Deyab SS, Kim HC, Khil MS. 2015. Monodispersed 3D MnWO₄–TiO₂ composite nanoflowers photocatalysts for environmental remediation. Curr Appl Phys, 15(6): 753–758. https://doi.org/10.1016/j.cap.2015.03.022
11. He HY, Huang JF, Cao LY, Wu JP. 2010. Photodegradation of methyl orange aqueous on MnWO₄ powder under different light resources and initial pH. Desalination, 252(1): 66–70. https://doi.org/10.1016/j.desal.2009.10.024
12. Jayakumar P, Palani S, Nallathambi M, Kuppusamy K. 2024. Evaluation of MnWO₄ nanomaterial for enhanced photocatalytic degradation activity over methyl orange. Lett Appl NanoBioSci, 13(1): 1. https://doi.org/10.33263/lianbs131.001
13. Kayhan E. 2025. Temperature-controlled synthesis of bismuth tungstate with enhanced photochromic properties. Int J Appl Ceram Technol, 22(3): e15079. https://doi.org/10.1111/ijac.15079
14. Kayhan M, Aksoy M, Kayhan E. 2024. A facile synthesis of photocatalytic Fe(OH)₃ nanoparticles for degradation of phenol. ChemistrySelect, 9(23): e202401367. https://doi.org/10.1002/slct.202401367
15. Kayhan M, Kayhan E. in press. Synthesis, characterization, and photocatalytic performance evaluation of manganese tungstate for methyl red dye degradation. Pamukkale Univ J Eng Sci, in press: 0 0. https://doi.org/10.5505/pajes.2025.27723
16. Kayhan M. 2025. Comparative study of photochromic behavior of bismuth tungstate via different surfactants. Ceram Int, 51(14): 19579–19588. https://doi.org/10.1016/j.ceramint.2025.02.133
17. Khaksar M, Boghaei DM, Amini M. 2015. Synthesis, structural characterization and reactivity of manganese tungstate nanoparticles in the oxidative degradation of methylene blue. C R Chim, 18(2): 199–203. https://doi.org/10.1016/j.crci.2014.04.004
18. Kumar KS, Vaishnavi K, Venkataswamy P, Ravi G, Ramaswamy K, Vithal M. 2021. Photocatalytic degradation of methylene blue over N-doped MnWO₄ under visible light irradiation. J Indian Chem Soc, 98(10): 100140. https://doi.org/10.1016/j.jics.2021.100140
19. Li R, Du Y, Tang C, Huang Y, Han G. 2025. Photocatalytic degradation of azo dye wastewater by thermal stripping of g-C₃N₄. In: Al-Majali Y, Wisner B, Mastorakos IN, Hunyadi Murph SE, Paramsothy M (eds) Advances in Sustainable Composites. TMS 2025. Springer, Cham. https://doi.org/10.1007/978-3-031-81057-2_17
20. Luo S, Ke J, Yuan M, Zhang Q, Xie P, Deng L, Wang S. 2018. CuInS₂ quantum dots embedded in Bi₂WO₆ nanoflowers for enhanced visible light photocatalytic removal of contaminants. Appl Catal B Environ, 221: 215–222. https://doi.org/10.1016/j.apcatb.2017.09.028
21. Maya-Johnson S, Gracia L, Longo E, Andres J, Leite ER. 2017. Synthesis of cuboctahedral CeO₂ nanoclusters and their assembly into cuboid nanoparticles by oriented attachment. ChemNanoMat, 3(4): 228–232. https://doi.org/10.1002/cnma.201700005
22. Muthamizh S, Suresh R, Giribabu K, Manigandan R, Praveen Kumar S, Munusamy S, Narayanan V. 2015. MnWO₄ nanocapsules: synthesis, characterization and its electrochemical sensing property. J Alloys Compd, 619: 601–609. https://doi.org/10.1016/j.jallcom.2014.09.049
23. Nagaraja K, Mallika B, Arunpandian M, Ravindran E, Tae Hwan O. 2025. Green synthesis of gold-decorated BaTiO₃-ZnO nanocomposites using Arabic gum polymer for efficient photocatalytic degradation of emerging textile dyes, antimicrobial, and toxicological evaluation. Int J Biol Macromol, 311: 143396. https://doi.org/10.1016/j.ijbiomac.2025.143396
24. Nezzari A, Medina S, Khane Y, Boublenza H, Guezzoul M, Zoukel A, Amrani B. 2025. Photocatalytic degradation of brilliant green dye using Cu₂NiSnS₄ thin films under ultraviolet irradiation. Inorg Chem Commun, 174: 114021. https://doi.org/10.1016/j.inoche.2025.114021
25. Nogami A, Suzuki T, Katsufuji T. 2008. Second harmonic generation from multiferroic MnWO₄. J Phys Soc Jpn, 77(11): 115001. https://doi.org/10.1143/JPSJ.77.115001
26. Pirhashemi M, Habibi-Yangjeh A. 2018. Fabrication of novel ZnO/MnWO₄ nanocomposites with p-n heterojunction: visible-light-induced photocatalysts with substantially improved activity and durability. J Mater Sci Technol, 34(10): 1891–1901. https://doi.org/10.1016/j.jmst.2018.01.014
27. Rao A, Cölfen H. 2017. Facet control in nanocrystal growth. In: Atwood JL (Ed.), Comprehensive Supramolecular Chemistry II. Elsevier, pp: 129–156. https://doi.org/10.1016/B978-0-12-409547-2.12638-1
28. Rastin H, Dell’Angelo D, Sayede A, Badawi M, Habibzadeh S. 2025. Green and sustainable metal-organic frameworks (MOFs) in wastewater treatment: a review. Environ Res, 282: 122087. https://doi.org/10.1016/j.envres.2025.122087
29. Sahoo S, Reddy GBT, Mahamallik P. 2024. Sunlight-assisted photocatalytic degradation of methyl red using g-C₃N₄ as metal-free photocatalyst. In: Mazumder D (ed.) Sustainable Advanced Technologies for Environmental Management. Springer Proc Earth Environ Sci. Springer, Cham. https://doi.org/10.1007/978-3-031-64006-3_1
30. Shalini S, Sasikala T, Tharani D, Venkatesh R, Muthulingam S. 2024. Novel green CQDs/ZnO binary photocatalyst synthesis for efficient visible light irradiation of organic dye degradation. J Mol Liq, 410: 125525. https://doi.org/10.1016/j.molliq.2024.125525
31. Shamshad J, Ur Rehman R. 2025. Innovative approaches to sustainable wastewater treatment: a comprehensive exploration of conventional and emerging technologies. Environ Sci Adv, 4(2): 189–222. https://doi.org/10.1039/D4VA00136B
32. Shivaganga GS, Parameswara P, Mallikarjunaswamy C, Kumar KCS, Soundarya TL, Nagaraju G, Ranganatha VL. 2023. Green, nonchemical route for the synthesis of MnWO₄ nanostructures: photocatalytic and electrochemical performance. J Mater Sci Mater Electron, 34(25): 1791. https://doi.org/10.1007/s10854-023-11190-3
33. Siahsahlan M, Mohammadi Aref S, Naghshara H, Azmayesh R. 2025. The effects of reduced graphene oxide amount on the photocatalytic performance of TiO₂ nanoparticles for hydrogen evolution. Int J Hydrogen Energy, 142: 318–329. https://doi.org/10.1016/j.ijhydene.2025.05.411
34. Vosoughifar M. 2017. Preparation, characterization, and morphological control of MnWO₄ nanoparticles through novel method and its photocatalyst application. J Mater Sci Mater Electron, 28(2): 2135–2140. https://doi.org/10.1007/s10854-016-5777-6
35. Wang G, Xu J, Sun Z, Zheng S. 2020. Surface functionalization of montmorillonite with chitosan and the role of surface properties on its adsorptive performance: a comparative study on mycotoxins adsorption. Langmuir, 36(10): 2601–2611. https://doi.org/10.1021/acs.langmuir.9b03673
36. Wu W, Qin W, He Y, Wu Y, Wu T. 2012. The effect of pH value on the synthesis and photocatalytic performance of MnWO₄ nanostructure by hydrothermal method. J Exp Nanosci, 7(4): 390–398. https://doi.org/10.1080/17458080.2010.533293
37. Xue W, He H, Zhu J, Yuan P. 2007. FTIR investigation of CTAB–Al–montmorillonite complexes. Spectrochim Acta A Mol Biomol Spectrosc, 67(3): 1030–1036. https://doi.org/10.1016/j.saa.2006.09.024
38. Zargazi M, Entezari MH. 2019. Sonochemical versus hydrothermal synthesis of bismuth tungstate nanostructures: photocatalytic, sonocatalytic and sonophotocatalytic activities. Ultrason Sonochem, 51: 1–11. https://doi.org/10.1016/j.ultsonch.2018.10.010
39. Zhang D, Otitoju TA, Ouyang Y, Shoparwe NF, Wang S, Li S. 2021. A review on metal ions modified TiO₂ for photocatalytic degradation of organic pollutants. Catalysts, 11(9): 1039. https://doi.org/10.3390/catal11091039
40. Zheng M, Zhang H, Gong X, Xu R, Xiao Y, Dong H, Liu Y. 2013. A simple additive-free approach for the synthesis of uniform manganese monoxide nanorods with large specific surface area. Nanoscale Res Lett, 8(1): 166. https://doi.org/10.1186/1556-276X-8-166