Preparation of Photocatalytic TiO<sub>2</sub> Filter by Chemical Surface Treatment from Ti Non-Woven Fabric

Abstract

Photocatalytic titanium dioxide (TiO2) filter was prepared by hydrothermal treatment in NaOH (8M) at 80°C followed by ion exchange in HCl (0.1M), and calcination at 400°C from Ti non-woven fabric (NIKKO TECHNO, Ltd.). Ti non-woven fabric is made of metallic Ti fibers. The surface area of the fabric is several times larger than flat Ti plate, so the TiO2 filter prepared from it should have high degradation ability of organic pollutants by photocatalyst. And we thought it could be applied for the filter to purify air or water. The sample was investigated by scanning electron microscope (SEM), and energy dispersive x-ray spectrometer (EDS). The photocatalytic activity of the sample was evaluated by degradation of methylene blue (MB) solution. The change of concentration of MB solution was measured by ultraviolet visible spectrometer (UV-vis). After the hydrothermal treatment, micro network structure layer was formed on the surface of Ti. The structure was maintained after heat treatment. The elements of the layer after heat treatment were Ti and O. The sample exhibited the degradation ability of MB solution. We tried to hybridize of the TiO2 filter and hydroxy apatite (HAp : Ca10(PO4)6(OH2) ) to improve degradation efficiency by adsorption ability of HAp. The hybrid material of them were prepared by soaking the TiO2 filter into simulated body fluid (SBF) at 37.5°C for 1~7d. Then, HAp particles were formed on the surface of the TiO2 filter. But the degradation ability was lower than non-hybrid sample.