Fabrication of titania/hydroxyapatite composite granules for photo-catalyst

The titania/hydroxyapatite composite granular photo-catalyst with novel microstructure was fabricated by the process based on the liquid immiscibility effect and followed by precalcination and hydrothermal treatment from commercially available powders of alpha-Tri-calcium phosphate and TiO2- XRD, SEM, BET, optical microscopy and UV-vis spectrophotometer were applied to characterize the prepared photocatalyst. Microstructure analysis indicated that the granule was weaved by rod-shaped hydroxyapatite crystals whose surface was covered by nano-sized TiO2. In the composite granules, the active surface of anatase was retained effectively. With the hybridization of TiO2 and HAp, a 16-nm blue-shift of absorption edge could be observed and the crystallinity of anatase could be enhanced by precalcination. The granules with the rod-shaped hydroxyapatite crystals performing as scaffold work as threedimensional high porous, size-controllable small reactor. The phase and microstructure transformation of the granule before and after hydrothermal treatment was investigated and its decomposition ability was evaluated by using Methylene blue as a target pollutant compound. (C) 2008 Elsevier Ltd. All rights reserved.