Optimization of Methyl Orange Removal from Aqueous Solutions Using Sol–Gel Synthesized TiO2–ZnO Nanophotocatalyst: Application of Response Surface Methodology (RSM)

Shahsavari, Sajad; Shafeeyan, Mohammad Saleh

doi:10.22112/jwwse.2026.540204.1459

Optimization of Methyl Orange Removal from Aqueous Solutions Using Sol–Gel Synthesized TiO2–ZnO Nanophotocatalyst: Application of Response Surface Methodology (RSM)

Articles in Press

Authors

Sajad Shahsavari ¹

Mohammad Saleh Shafeeyan ²

¹ Graduate Master Student

² Academic Staff

10.22112/jwwse.2026.540204.1459

Abstract

In this study, TiO₂–ZnO nanocomposites were synthesized via the sol–gel method in three different weight ratios (1:3, 1:1, and 3:1) to enhance their photocatalytic performance. The synthesized nanocomposites were thoroughly characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR), and UV–Vis spectroscopy to evaluate their crystal structure, surface morphology, functional groups, optical band gap, and light absorption characteristics. The photocatalytic activity of the nanocomposites was investigated for the degradation of methyl orange dye in aqueous solution under ultraviolet (UV) irradiation. Experimental design and statistical modeling were performed using response surface methodology to predict the dye removal efficiency as a function of four key operational variables: UV light intensity, initial dye concentration, reaction time, and catalyst dosage. Analysis of variance confirmed the statistical significance and robustness of the developed quadratic regression model, with a high coefficient of determination (R2 > 0.99) and a p-value below 0.0001, indicating excellent predictive capability and model accuracy. The optimal conditions for achieving the maximum dye removal efficiency of 96.36% were determined to be an initial dye concentration of 13.68 ppm, UVA irradiation at 17.55 W, a reaction time of 2.37 h, and a catalyst dosage of 0.62 g/L.

Keywords

Nanophotocatalyst, Sol&ndash

Gel, TiO2, ZnO, Methyl Orange