Preparation of a hydroxyapatite-supported titanium oxide via the hydrothermal method for photocatalytic degradation of textile dyes

Abstract

In this study, the HAP-based adsorbent and photocatalytic materials, including hydroxyapatite synthesised from Ca(NO₃)₂ and NH₄H₂PO₄ precursors and titanium oxide-immobilised HAP (TiO₂/HAP) derived from TiCl₃, were produced using a hydrothermal method. The obtained materials were characterised by several techniques: X-ray diffraction, scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM/EDX), and surface charge determination via zeta potential measurements. The adsorption and photocatalytic performances of the materials were evaluated through degradation experiments of methylene blue (MB), alizarin yellow G (AYG), and indigo dye (XHT - textile dye collected from household-scale traditional weaving villages), with dye concentrations before and after treatment determined by UV-Vis spectrophotometry. Characterisation results indicated that titanium oxide was successfully immobilised and uniformly dispersed within the HAP matrix, and the particles exhibited good stability in the dispersion medium. The TiO₂/HAP composite exhibited photocatalytic oxidation and degradation efficiencies exceeding 90% for all tested dyes after three hours of UV irradiation. This highlights the potential application of TiO₂/HAP composite materials in the photocatalytic treatment of dye pollutants.