DOI: https://doi.org/10.9767/bcrec.20411

Kinetics Model and Optimization for Photocatalytic Degradation of Methylene Blue over Ag/TiO2 Catalyst

School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia

Received: 10 Jun 2025; Revised: 1 Aug 2025; Accepted: 1 Aug 2025; Available online: 12 Aug 2025; Published: 31 Oct 2025.
Editor(s): Istadi Istadi
Open Access Copyright (c) 2025 by Authors, Published by BCREC Publishing Group
Creative Commons License This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Fulltext View|Download

Citation Format:
Cover Image
Abstract

Titanium dioxide (TiO2) particles are widely used as photocatalysts due to their stability, low toxicity, and relatively low cost. However, their application is limited by a wide bandgap and a high recombination rate. This project investigated the photocatalytic performance of Ag/TiO2 catalyst, prepared by coupling Ag metal to TiO2 using the liquid impregnation method. The photocatalytic activity of different concentrations of Ag metal solutions and different pH levels of Ag/TiO2 catalyst under UV and visible light irradiation was observed. It was shown that Ag/TiO2 catalyst had the best photodegradation efficiency (83.82%) and the highest rate constant (0.03298 min-1) in 50 ppm Ag metal concentration and at pH 5 under UV light irradiation. The operating conditions were optimised by using the Design of Experiment (DOE) and Response Surface Methodology (RSM) to obtain optimum photodegradation efficiency (PE). The optimum parameters were 22.6263 ppm Ag metal solution and pH of 5, which were estimated to produce the highest photodegradation efficiency (84.0006 %) and rate constant (0.0321 min-1). The concentration of the methylene blue (MB) followed a first-order exponential decay and showed a decreasing trend from its initial concentration. In addition, the photocatalytic degradation rate of MB has been modelled successfully by Power Law kinetic model derived from the Langmuir-Hinshelwood framework. Numerical and analytical methods were implemented to solve the Langmuir-Hinshelwood equation, and both methods were very effective in agreement with the trend shown by the experimental data. In terms of photodegradation efficiency, the kinetic model has slightly over predicted the experimental model due to some minor experimental error, but the experimental data effectively complied with the theoretical micro kinetics investigations simulated using Power Law kinetic model. Copyright © 2025 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Supporting Information (SI) PDF
Keywords: Photodegradation; Photocatalyst; TiO2; Ag/TiO2; Langmuir-Hinshelwood Model
Funding: Ministry of Higher Education Malaysia under contract FRGS/1/2022/STG05/USM/03/3

Article Metrics:

Article Info
Section: Original Research Articles
Language : EN
Recent articles
Salt-Assisted Mesostructured Cellular Foam (MCF) Silica Synthesis from Bagasse Bottom Ash for Enzymatic Starch Hydrolysis Eco-Friendly Photocatalyst from Limestone: ZnO-Hydroxyapatite Composite for Efficient Rhodamine B Removal Investigation of Ar/CH₄ Mixtures in Dielectric Barrier Discharge: A Simulation Approach for Hydrogen Production Frontmatter (Front Cover, Editorial Team, Indexing, and Table of Contents) Backmatter (Publication Ethics, Right Transfer Agreement for Publishing Form) More recent articles
  1. Kapdan, I.K., Kargi, F. (2002). Simultaneous biodegradation and adsorption of textile dyestuff in an activated sludge unit. Process Biochemistry, 37 (9), 973–981. DOI: 10.1016/S0032-9592(01)00309-0
  2. Kadirvelu, K., Kavipriya, M., Karthika, C., Radhika, M., Vennilamani, N., Pattabhi, S. (2003). Utilization of various agricultural wastes for activated carbon preparation and application for the removal of dyes and metal ions from aqueous solutions. Bioresource Technology, 87(1), 129–132. DOI: 10.1016/S0960-8524(02)00201-8
  3. Riente, P., Noël, T. (2019). Application of metal oxide semiconductors in light-driven organic transformations. Catalysis Science & Technology, 9(19), 5186–5232. DOI: 10.1039/c9cy01170f
  4. Han, M., Zhu, S., Lu, S., Song, Y., Feng, T., Tao, S., Liu, J., Yang, B. (2018). Recent progress on the photocatalysis of carbon dots: Classification, mechanism and applications. Nano Today, 19, 201–218. DOI: 10.1016/j.nantod.2018.02.008
  5. Zhang, W., Zhang, S., Wang, J., Wang, M., He, Q., Song, J., Wang, H., Zhou, J. (2018). Hybrid functionalized chitosan‑Al₂O₃@SiO₂ composite for enhanced Cr(VI) adsorption. Chemosphere, 203, 188–198. DOI: 10.1016/j.chemosphere.2018.03.188
  6. Diaz-Angulo, J., Gomez-Bonilla, I., Jimenez-Tohapanta, C., Mueses, M., Pinzon, M., Machuca-Martinez, F. (2019). Visible-light activation of TiO2 by dye-sensitization for degradation of pharmaceutical compounds. Photochemical & Photobiological Sciences, 18(4), 897–904. DOI: 10.1039/c8pp00270c
  7. Chong, M.N., Jin, B., Chow, C.W.K., Saint, C. (2010). Recent developments in photocatalytic water treatment technology: A review. Water Research, 44(10), 2997–3027. DOI: 10.1016/j.watres.2010.02.039
  8. Sébastien, S. (2012). Les soignants face à la mort. Revue Infirmière, 1(180), 39–41
  9. Yaqoob, A.A., Parveen, T., Umar, K., Mohamad Ibrahim, M.N. (2020). Role of nanomaterials in the treatment of wastewater: A review. Water, 12(2), 495. DOI: 10.3390/w12020495
  10. Chauke, N.M., Ngqalakwezi, A., Raphulu, M. (2025). Transformative advancements in visible-light-activated titanium dioxide for industrial wastewater remediation. International Journal of Environmental Science and Technology, 22, 8521–8552. DOI: 10.1007/s13762-025-06397-2
  11. Lee, S.-Y., Park, S.-J. (2013). TiO₂ photocatalyst for water treatment applications. Journal of Industrial and Engineering Chemistry, 19(6), 1761–1769. DOI: 10.1016/j.jiec.2013.07.012
  12. Huang, Z., Gao, Z., Gao, S., Wang, Q., Wang, Z., Huang, B., Dai, Y. (2017). Facile synthesis of S doped reduced TiO2 x with enhanced visible light photocatalytic performance. Chinese Journal of Catalysis, 38(5), 821–830. DOI: 10.1016/S1872-2067(17)62825-0
  13. Micheal, K., Ayeshamariam, A., Boddula, R., Arunachalam, P., Al Salhi, M.S., Theerthagiri, J., Prasad, S., Madhavan, J., Al Mayouf, A.M. (2019). Assembled composite of hematite iron oxide on sponge like BiOCl with enhanced photocatalytic activity. Materials Science in Energy Technology, 2(1), 104–111. DOI: 10.1016/j.mset.2018.11.004
  14. Yin, S., Zhang, Q., Saito, F., Sato, T. (2003). Preparation of visible light-activated titania photocatalyst by mechanochemical method. Chemistry Letters, 32(4), 358–359. DOI: 10.1246/cl.2003.358
  15. Moma, J., Baloyi, J. (2019). Modified Titanium Dioxide for Photocatalytic Applications. Photocatalysts - Applications and Attributes (p. 18). DOI: 10.5772/intechopen.79374
  16. Widiyandari, H., Nashir, M., Parasdila, H., Almas, K.F., Suryana, R. (2023). Ag-TiO2 for efficient methylene blue photodegradation under visible light irradiation. Bulletin of Chemical Reaction Engineering & Catalysis, 18(4), 593–603. DOI: 10.9767/bcrec.19885
  17. Feng, S., Wang, M., Zhou, Y., Li, P., Tu, W., Zou, Z. (2015). Double shelled plasmonic Ag TiO₂ hollow spheres toward visible light active photocatalytic conversion of CO₂ into solar fuel. APL Materials, 3(10), 104416. DOI: 10.1063/1.4930043
  18. Cai, P.-F., Li, J., Wu, X.-B., Li, Z.-Y., Shen, J., Nie, J.-J., Cui, Z.-D., Chen, D.-F., Liang, Y.-Q., Zhu, S.-L., Wu, S.-L. (2022). ALD-induced TiO₂/Ag nanofilm for rapid surface photodynamic ion sterilization. Rare Metals, 41(12), 4138–4148. DOI: 10.1007/s12598-022-02096-w
  19. Jarandehei, A., Golpayegani, M.K., De Visscher, A. (2008). Kinetic modeling of photocatalytic degradation reactions: Effect of charge trapping. Applied Catalysis B: Environmental, 84(1–2), 65–74. DOI: 10.1016/j.apcatb.2008.03.006
  20. Kumar, K.V., Porkodi, K., Rocha, F. (2008). Langmuir Hinshelwood kinetics – A theoretical study. Catalysis Communications, 9(1), 82–84. DOI: 10.1016/j.catcom.2007.05.019
  21. Chen, W.-T., Chan, A., Sun Waterhouse, D., Llorca, J., Idriss, H., Waterhouse, G.I.N. (2018). Performance comparison of Ni/TiO2 and Au/TiO2 photocatalysts for H2 production in different alcohol–water mixtures. Journal of Catalysis, 367, 27–42. DOI: 10.1016/j.jcat.2018.08.015
  22. Kim, M.G., Kang, J.M., Lee, J.E., Kim, K.S., Kim, K.H., Cho, M., Lee, S.G. (2021). Effects of calcination temperature on the phase composition, photocatalytic degradation, and virucidal activities of TiO2 nanoparticles. ACS Omega, 6(16), 10668-10678. DOI: 10.1021/acsomega.1c00043
  23. Komaraiah, D., Radha, E., Sivakumar, J., Ramana Reddy, M.V., Sayanna, R. (2020). Photoluminescence and photocatalytic activity of spin coated Ag⁺ doped anatase TiO₂ thin films. Optical Materials, 108, 110401. DOI: 10.1016/j.optmat.2020.110401
  24. Wang, W., Serp, P., Kalck, P., Faria, J.L. (2005). Photocatalytic degradation of phenol on MWNT and titania composite catalysts prepared by a modified sol-gel method. Applied Catalysis B: Environmental, 56(4), 305–312. DOI: 10.1016/j.apcatb.2004.10.036
  25. Kumar, R., Rashid, J., Barakat, M.A. (2015). Zero valent Ag deposited TiO₂ for the efficient photocatalysis of methylene blue under UV C light irradiation. Colloids and Interface Science Communications, 5, 1–4. DOI: 10.1016/j.colcom.2015.05.001
  26. Padmanaban, A., Dhanasekaran, T., Kumar, S. P., Gnanamoorthy, G., Munusamy, S., Stephen, A., Narayanan, V. (2017). Visible light photocatalytic property of Ag/TiO2 composite. Mechanics, Materials Science & Engineering Journal, 9(1).‏ DOI: 10.2412/mmse.97.67.748
  27. Pelaez, M., Nolan, N.T., Pillai, S.C., Seery, M.K., Falaras, P., Kontos, A.G., Dunlop, P.S.M., Hamilton, J.W.J., Byrne, J.A., O’Shea, K., Entezari, M.H., Dionysiou, D.D. (2012). A review on the visible light active titanium dioxide photocatalysts for environmental applications. Applied Catalysis B: Environmental, 125, 331–349. DOI: 10.1016/j.apcatb.2012.05.036
  28. Kadem, A.J., Teo, Y.X., Pung, S., Sreekantan, S., Ramakrishnan, S. (2023). Predicting photocatalytic properties of metal coupled Mn-TiO2 particle using response surface methodology (RSM) as a potential filler in LED’s encapsulant. Bulletin of Chemical Reaction Engineering & Catalysis, 18(2), 238-255. DOI: 10.9767/bcrec.18020
  29. Chakhtouna, H., Benzeid, H., Zari, N., Qaiss, A.E.K., Bouhfid, R. (2021). Recent progress on Ag/TiO2 photocatalysts: Photocatalytic and bactericidal behaviors. Environmental Science and Pollution Research, 28(33), 44638–44666. DOI: 10.1007/s11356-021-14996-y
  30. Jodat, A., Jodat, A. (2014). Photocatalytic degradation of chloramphenicol and tartrazine using Ag/TiO2 nanoparticles. Desalination and Water Treatment, 52(13–15), 2668–2677. DOI: 10.1080/19443994.2013.794115
  31. Jiang, D., Kusdianto, K., Kubo, M., Shimada, M. (2020). Effect of Ag loading content on morphology and photocatalytic activity of Ag-TiO2 nanoparticulate films prepared via simultaneous plasma-enhanced chemical and physical vapor deposition. Materials Research Express, 7(11), 116406. DOI: 10.1088/2053-1591/abc720
  32. Kulkarni, R.M., Malladi, R.S., Hanagadakar, M.S., Doddamani, M.R., Bhat, U.K. (2016). Ag-TiO2 nanoparticles for photocatalytic degradation of lomefloxacin. Desalination and Water Treatment, 57(34), 16111-16118. DOI: 10.1080/19443994.2015.1076352
  33. Lantos, E., Mérai, L., Deák, Á., Gómez-Pérez, J., Sebők, D., Dékány, I., Kónya, Z., Janovák, L. (2020). Preparation of sulfur hydrophobized plasmonic photocatalyst towards durable superhydrophobic coating material. Journal of Materials Science & Technology, 41, 159-167. DOI: 10.1016/j.jmst.2019.04.046
  34. Tang, J., Zou, Z., Ye, J. (2005). Kinetics of MB degradation and effect of pH on the photocatalytic activity of MIn2O4 (M= Ca, Sr, Ba) under visible light irradiation. Research on chemical intermediates, 31(4), 513-519. DOI: 10.1163/1568567053956699
  35. Saeed, M., Muneer, M., Khosa, M., Akram, N., Khalid, S., Adeel, M., Nisar, A. Sherazi, S. (2019). Azadirachta indica leaves extract assisted green synthesis of Ag-TiO2 for degradation of Methylene blue and Rhodamine B dyes in aqueous medium. Green Processing and Synthesis, 8(1), 659-666. DOI: 10.1515/gps-2019-0036
  36. Schneider, J., Matsuoka, M., Takeuchi, M., Zhang, J., Horiuchi, Y., Anpo, M., Bahnemann, D.W. (2014). Understanding TiO₂ photocatalysis: Mechanisms and materials. Chemical Reviews, 114(19), 9919–9986. DOI: 10.1021/cr5001892
  37. Khataee, A.R., Kasiri, M.B. (2010). Photocatalytic degradation of organic dyes in the presence of nanostructured titanium dioxide: Influence of the chemical structure of dyes. Journal of Molecular Catalysis A: Chemical, 328(1-2), 8-26. DOI: 10.1016/j.molcata.2010.05.023
  38. Le, A.T., Pung, S.Y., Chiam, S.L., Josoh, N.B.N., Koay, T.Y., Lee, J.S., Mustar, N.B. (2020, September). Photocatalytic performance of TiO2 particles in degradation of various organic dyes under visible and UV light irradiation. In AIP Conference Proceedings (Vol. 2267, No. 1, p. 020017). AIP Publishing LLC. DOI: 10.1063/5.0016025

Last update:

No citation recorded.

Last update:

No citation recorded.