漂浮型光催化剂制备及其除藻性能初探

Preparation of Floating Photocatalyst for Inactivation of Algae Cells

摘要:

以膨胀石墨为载体，蔗糖为外覆炭层前驱物，采用溶胶炭化一步制备膨胀石墨复合炭基氮、磷共掺杂二氧化钛复合材料（NPTEGC），通过场发射扫描电子显微镜（FESEM）、氮吸附比表面积及孔容孔径分析仪（BET）、X射线衍射仪（XRD）、紫外可见漫反射光谱仪（UVvis DRS）、X射线光电能谱仪（XPS）和傅里叶变换红外光谱仪（FTIR）等分析手段进行材料表征，考察不同煅烧温度制备的材料的除藻性能.实验结果表明，NPTEGC复合材料具有蠕虫状的空间结构，表面覆有均匀的二氧化钛颗粒.氮、磷以掺杂的方式进入二氧化钛晶格，其中氮主要通过取代氧的方式，而磷主要通过取代钛的方式.掺杂后复合材料的光能吸收率明显提高.考察不同煅烧温度下制备的NPTEGC材料对铜绿微囊藻的去除性能发现，相对于无催化剂和无光催化负载的情况，复合材料NPTEGC的除藻性能有明显提高，其中以450 ℃下制备的NPTEGC除藻效果最好，9 h的藻细胞去除率在98 %以上.另外，漂浮型的材料易被分离回收，更有利于光能转化，在环境污染治理中应用前景广阔.

Abstract:

The floating photocatalysts of NP codoped TiO2 grafted on expanded graphite C/C composite (NPTEGC) were prepared by a onestep solcarbonization method. The catalysts were characterized by fieldemission scanning electron microscopy (FESEM), brunaueremmettteller (BET), Xray diffraction (XRD), UVvis diffuse reflectance spectrum (UVvis DRS), Xray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The results show that NPTEGC (NP codoped TiO2/expanded graphite C/C composites) has a wormlike 3D structure and TiO2 particles can be seen on the surface of EGC. As for the doping elements, N doped into the TiO2 crystal lattice mainly by the substitution of lattice O while P doped into the TiO2 crystal lattice mainly by the substitution of lattice Ti. After NP codoping, the light adsorption scale of the composites has been significantly improved. The properties of photocatalytic inactivation of algae cells by NPTEGC with different calcination temperature were investigated. Comparing with the condition of no catalyst adding or no photocatalyst loading, NPTEGC composites have a significant advantage in inactivation of algae cells. The optimal type of NPTEGC was synthesized at the calcination temperature of 450 ℃ and the removal rate for 9 h was above 98 %. Moreover, the floating materials could be easily separated and reused, showing great potential for practical applications in environmental cleanup and solar energy conversion.