Tarmizi Taher, Asri Saffanah Pratiwi, Sephia Amanda Muhtar, Adri Huda, Mhd Yasin Siregar, Yu Zhongliang, Dian Ahmad Hapidin, Khairurrijal Khairurrijal, Aditya Rianjanu
Zinc-doped Nb2O5 nanoparticles with deformed orthorhombic structure were synthesized via hydrothermal method using ammonium niobium oxalate and evaluated for synergetic adsorption–photocatalytic removal of organic dyes. Comprehensive characterization (XRD, FTIR, Raman, XRF, SEM-EDS, UV–Vis DRS, LR-TEM/SAED, and photoluminescence) confirmed Zn incorporation (1–10 mol%) into the microporous framework without modification of the bulk electronic structure. Zn5/Nb2O5 achieved the highest dye removal efficiency (∼80%) after 180 min under UV irradiation, significantly outperforming undoped Nb2O5. Maximum adsorption capacities were 26.9 mg/g (crystal violet, CV) and 66.1 mg/g (methylene blue, MB), following Langmuir and Temkin isotherm models, respectively. Optimal performance occurred at pH 8. A decoupled scavenger experiment, combined with FTIR and COD analyses of the post-reaction solid and solution, identified superoxide radical ( [Figure presented] ) as the dominant reactive species, with hole (h+) oxidation as a secondary pathway and a minor role for hydroxyl radicals (•OH); the dye chromophore was destroyed at the catalyst surface, although a residual organic load in the filtrate indicates that full mineralization to CO2/H2O is not reached under the present conditions. The enhanced activity is attributed to the Zn-induced increase in cationic-dye adsorption capacity and to interfacial charge transfer at a local heterojunction with a minor Zn-rich secondary phase, rather than to band-gap modification (3.12–3.14 eV) or to suppression of bulk electron–hole recombination. This work demonstrates Zn-doped Nb2O5 with deformed orthorhombic structure as an efficient bifunctional material for wastewater treatment. © 2026 Elsevier B.V.
Department of Environmental Engineering, Faculty of Infrastructure and Regional Technology, Institut Teknologi Sumatera, Terusan Ryacudu, Way Hui, Jati Agung, Lampung, Selatan, 35365, Indonesia; Center for Green and Sustainable Materials, Institut Teknologi Sumatera, Terusan Ryacudu, Way Hui, Jati Agung, Lampung, Selatan, 35365, Indonesia; Department of Environmental Engineering, Faculty of Civil and Environmental Engineering, Institut Teknologi Bandung, Bandung, 40132, Indonesia; Department of Environmental Engineering, Faculty of Engineering, Universitas Sumatera Utara, Medan, Indonesia; Department of Materials Engineering, Faculty of Industrial Technology, Institut Teknologi Sumatera, Terusan Ryacudu, Way Hui, Jati Agung, Lampung, Selatan, 35365, Indonesia; School of Chemistry and Environmental Science, Shangrao Normal University, Shangrao, 334001, China; Research Group of Physics and Technology of Advanced Materials, Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesa No. 10, Jawa Barat, Bandung, 40132, Indonesia