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Degradation of environmental hormone by visible light active double layer photocatalyst

可见光活性双层光触媒降解环境激素

基本信息

批准号：
18510070
负责人：
TAKAHASHI Takakazu
金额：
$ 2.55万
依托单位：
University of Toyama
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18510070/
关键词：
Photocatalyst Titanium dioxide Tungsten trioxide Visible light Sputter film Environmental hormone 17β-estradiol HPLC

项目摘要

We have prepared photocatalytic TiO_2 films by reactive DC sputtering from Ti pure metal and mixture gas of Ar+O_2. The degradation of water solution containing 17β-estradiol well known as female sex environmental hormone was performed under irradiation of UV light to the surface of TiO_2 film set up in the water solution. The concentrations of 17β-estradiol in the water solution were estimated from the measurement of HPLC in intervals during UV light was turned on. At initial stage, the degradation rate was faster with increasing UV light intensity After irradiation period was six hours, the degradation rate was saturated and independent of UV light intensity The degradation rate was different in the films deposited at different sputtering pressure. This may be due to the difference of surface area and porosity in the films.To enhance the photocatalytic activity to visible light in solar light, we have prepared the double-layered photocatalyst composed of TiO_2 and WO_3 films. First, the WO_3 films were deposited on glass substrates by reactive sputtering. We annealed the as-deposited WO_3 films to improve the crystallinity, optical properties and surface microstructure. Then, TiO_2 films were deposited on the annealed WO_3 films by reactive sputtering. The 17β-estradiol was decomposed by the double-layered photocatalyst under irradiation of artificial solar light to the surface of TiO_2 film. The concentrations of 17β-estradiol were also estimated from HPLC, during the artificial solar light was turned on. When six hours passed after the light was turned on, the degradation rates of 17β-estradiol water solution were obtained as a values of 45% for single-layered TiO_2 films, and 57% for the double-layered photocatalyst, respectively.These results suggest that WO_3 under layer in double-layered photocatalyst could be effectively activated for visible light and assist with the enhancement of photocatalytic activity of TiO_2 upper layer.

以Ti纯金属和Ar+O_2混合气体为原料，采用直流反应溅射法制备了TiO_2光催化薄膜。以17β-雌二醇（雌激素）为环境激素，在紫外光照射下，在TiO_2薄膜表面沉积TiO_2薄膜，研究其对雌激素的降解作用。在紫外光照射的初始阶段，随着紫外光强度的增加，17β-雌二醇的降解速率加快，照射6 h后，降解速率达到饱和，与紫外光强度无关，不同溅射气压下沉积的薄膜降解速率不同。这可能是由于薄膜的比表面积和孔隙率的差异造成的。为了提高太阳光中可见光的光催化活性，我们制备了由TiO_2和WO_3薄膜组成的双层光催化剂。首先，采用反应溅射法在玻璃基片上沉积了WO_3薄膜。我们对沉积态的WO_3薄膜进行了退火处理，以改善薄膜的结晶性、光学性能和表面微结构。然后，采用反应溅射法在退火后的WO_3薄膜上沉积TiO_2薄膜。在人造太阳光照射下，双层光催化剂能够分解17β-雌二醇。在人工日光照射下，17 β-雌二醇水溶液的降解率为45%（单层TiO_2膜）和57%（双层TiO_2膜）。结果表明，双层光催化剂中的底层WO_3能有效地活化可见光，并有助于提高上层TiO_2的光催化活性。