Because hydroxyapatite (HAp) shows the unique adsorption property, we speculate that HAp is a suitable catalyst supports. In this study, TiO2 nanoparticles are dispersed on HAp (TiO2-modified HAp) that was synthesized by hydrothermal treatment using urea. Using add fuchsin (AF), the photocatalytic decolouration and adsorption tests were performed to investigate the effects of HAp characteristics and compositions. The morphology of HAp was changed from needle- to sponge-shaped by increasing the urea concentration. Concurrently, the TiO2 nanoparticle formed on the HAp. The photocatalytic decolouration rate of TiO2-modifed HAp with sponge-shaped crystals, which shows a high surface area and high zeta potential, was slightly higher than the rate in the presence of needle-shaped crystals. Therefore, this study discusses the effects of the HAp morphology and TiO2 nanoparticle count properties that influences adsorption properties. This information can be used to produce more efficient adsorption materials and processes. (C) 2020 Elsevier B.V. All rights reserved.