Preparation of TiO2/Hydroxyapatite Composite and Its Photocatalytic Degradation of Methyl Orange

A TiO2/hydroxyapatite composite (Ti-HAP) was prepared by a hydrothermal method with hydroxyapatite and titanium sulfate and tested for photocatalytic degradation of methyl orange with an 8 W ultraviolet (UV) lamp irradiation. The properties of Ti-HAP were characterized by X-ray diffraction, scanning electron microscope, and Fourier transform infrared spectroscopy (FT-IR) analysis. The effect of the Ti/(Ca+Ti) mole ratio on the photocatalytic degradation efficiency of methyl orange by Ti-HAP and the photocatalytic degradation dynamics were investigated. The results show that the addition of Ti slightly changes the structure of HAP. A higher Ti/(Ca+Ti) mole ratio results in the generation of anatase in Ti-HAP and higher removal efficiency of methyl orange by Ti-HAP under UV irradiation. The removal efficiency decreases with the initial content of methyl orange increasing from 10-200 mg/L. The photocatalytic degradation process of methyl orange by Ti-HAP and HAP follow the Langmuir-Hinshelwood kinetics model. DOI: 10.1061/(ASCE)EE.1943-7870.0000357. (C) 2011 American Society of Civil Engineers.