Preparation Of TiO₂Nanotubes And Synthesis Of TiO₂/Aspergillus Niger Composite Materials

One-dimensional nanomaterials such as nanotues、nanofibers、nanowires and nanorodshave raised much attention since Iijima discovered carbon nanotubes in1991. Because of ti’sgood biocompatibility, chemical stability, photocatalytic activity and many othercharacteristics, synthesis and application of TiO₂nanomaterials especially TiO₂nanotubes andother one-dimensional TiO₂nanomaterials are always hot research topics. One-dimensionalTiO₂nanomaterials have been used in light catalysis, catalyst supports, solar cells and otherfields as they have high surface area and good optical and electrical properties.Because of the surface effect, TiO₂and many other nanomaterials which have largesurface area and high surface energy are often used to purify water as adsorbents.Nanomaterials can purify waster water efficiently and with low pollution，but it is hard toreclaim as the material particle is too small. Integrate nanomaterials into the continuous phasematrix as a dispersed phase can solve the problem. In recent years, the combination withmicrobes and advanced materials such as realized in cell-semiconductor coupling or by usingsmall biological forms as templates for nanotechnological applications has become the focusof more and more interest. Studies have shown that some properties of composite materialsmade by nanomateials and microbes are close to the individual nanomaterials. In this article,we synthesis TiO₂nanotubes with nano Ti powder by hydrothermal synthesis, we use TEM,SEM, XRD and other testing methods to analyze the morphology, we also research theadsorption capacity to uranyl ion of the nanotube; we synthesis a composite material withTiO₂nanotube and Aspergillus niger, the factors and mechanism of the material are discussed.The main content of the article is as follows:1. One-dimensional nanomaterials were prepared by hydrothermal method with nano Tipowder and NaOH solution；products were confirmed to be TiO₂nanotube by TEM, XRD andSEM；when the materials were calcinated at400°C, the nanotube would turn to be anataseTiO₂which still had a tubular structure. we study radioactive adsorption capacity of TiO₂nanotube by uranyl ion adsorption experiments, the result shows that the nanotube canremove uranyl ion easily whether it is in high concentrations or low concentrations; the nanomaterials can remove uranyl ion selectively; calcinated at350°C, the nanotubes still haveadsorption capacity.2. We use TiO₂nanotubes as a discrete phase materials and Aspergillus niger bacteriaobtained from liquid cultures as the continuous phase matrix to synthesis TiO₂/Aspergillusniger composite materials in water environment. TiO₂nanotubes evenly distributed on thesurface of Aspergillus niger which can be seen by TEM clearly; we compared the uranyladsorption capacity between Aspergillus niger bacteria, TiO₂/Aspergillus niger compositematerials and TiO₂nanotubes.3. The impact of bacterial pre-processing、the rotation rate and time were studied.Synthesis mechanism of the composites was discussed by XRD and FT-IR, the result showsthat hydroxyl groups on cell surface play an important part in the synthesis of compositematerials.