Iranian Research Organization for Science and Technology Advances in Environmental Technology 2476-6674 12 3 2026 07 01 Titanium dioxide Sol–Gel/Zinc oxide Sol–Gel and Titanium dioxide Sol–Gel/powdered Zinc Oxide-coated clay beads in photocatalytic reactor 328 340 1681 10.22104/aet.2026.7628.2146 EN Thurgadewi Krishnan Faculty of Ocean Engineering Technology, University Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia 0000-0003-4597-0118 Maria Medina Llamasb Unidad Académica Preparatoria, Plantel II, Universidad Autónoma de Zacatecas, Zacatecas, Zac 98068, México 0000-0001-5094-3363 Mohamad Awanga Faculty of Ocean Engineering Technology, University Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia 0000-0002-6336-0156 Wan Rafizah Wan Abdullaha Faculty of Ocean Engineering Technology, University Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia 0000-0001-7806-3640 Wan Salida Wan Mansora Faculty of Ocean Engineering Technology, University Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia 0000-0001-8868-9479 Journal Article 2025 05 29 Nowadays, immobilized photocatalyst clay beads have attracted considerable research interest due to their outstanding properties, including enhanced stability, easy recovery and reuse, and reduced secondary pollution. In this study, novel titanium dioxide/zinc oxide composites were synthesized via the sol–gel method and immobilized on clay beads using the dip-coating process. Various titanium dioxide/zinc oxide ratios were used to obtain different composites. For the immobilization procedure, four titanium dioxide/zinc oxide layers were coated on clay beads, dried in the oven at 100°C for 30 min, and subsequently calcined at 2°C/min up to 500°C. The coated beads were characterized using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Photocatalytic degradation experiments were conducted to test their performance using methylene blue as a model pollutant. The highest methylene blue degradation efficiency was achieved with pure titanium dioxide-coated clay beads. All titanium dioxide/zinc oxide composites maintained their photocatalytic performance after five consecutive recyclability experiments. This work aims to demonstrate a reproducible, scalable, and economic immobilization procedure for single and composite photocatalysts on clay beads with outstanding photocatalytic performances for wastewater treatment. https://aet.irost.ir/article_1681_f50a6c02a3fc5a3a5d4d9391f05f3efc.pdf