State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China; Institute of Chemical Sciences, Gomal University D.I.Khan, KP, Pakistan.
State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
J Photochem Photobiol B. 2016 Sep;162:189-198. doi: 10.1016/j.jphotobiol.2016.06.039. Epub 2016 Jun 23.
Water purification is one of the worldwide problem and most of the conventional methods are associated with a number of drawbacks. Therefore it is the need of the day to develop new methods and materials to overcome the problem of water purification. In this research work we present a simple and green approach to synthesize silver decorated titanium dioxide (Ag/TiO2) nanocomposite with an efficient photo catalytic activities. Phytochemicals of the Cestrum nocturnum leaf extract were used to synthesize silver nanoparticles (AgNPs), Titanium dioxide (TiO2) and Ag/TiO2 nanocomposite. To confirm the formation, crystal structure, particle size and shape of green synthesized nanoparticles and nanocomposite, they were characterized by UV-visible spectroscopy (UV-vis), X-ray diffraction spectroscopy (XRD), high resolution transmission electron microscopy (HRTEM), Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The AgNPs, TiO2 and Ag/TiO2 were evaluated for photo degradation of methylene blue (MB) and photo inhibition of Bacteria. The bio-synthesized Ag/TiO2 nanocomposite was observed to have strong catalytic activities for photo reduction of MB and photo inactivation of bacteria as compared to bare AgNPs and TiO2. In the presence of Ag/TiO2, 90% of MB was degraded only in 40min of irradiation. Alternatively the bare AgNPs and TiO2 degraded less than 30% and 80% respectively of MB even in more than 100min of irradiation. Similarly the Ag/TiO2 has very strong photo inhibition efficiency towards Escherichia coli and Pseudomonas aeruginosa. The zone of inhibition of irradiated Ag/TiO2 nanocomposites against E. coli and P. aeruginosa was 19mm and 17mm respectively which was two times higher than in dark. These promising photocatalytic activities of nanocomposite may be due to the highly decorated AgNPs over the surface of TiO2.
水净化是全球性问题之一，大多数传统方法都存在一些缺点。因此，开发新的方法和材料来解决水净化问题是当务之急。在这项研究工作中，我们提出了一种简单而绿色的方法，用有效的光催化活性来合成银修饰的二氧化钛（Ag/TiO2）纳米复合材料。Cestrum nocturnum 叶提取物的植物化学物质被用来合成银纳米粒子（AgNPs）、二氧化钛（TiO2）和 Ag/TiO2 纳米复合材料。为了确认绿色合成的纳米粒子和纳米复合材料的形成、晶体结构、粒径和形状，它们通过紫外-可见光谱（UV-vis）、X 射线衍射光谱（XRD）、高分辨率透射电子显微镜（HRTEM）、扫描电子显微镜（SEM）和傅里叶变换红外光谱（FT-IR）进行了表征。AgNPs、TiO2 和 Ag/TiO2 被用于评价亚甲基蓝（MB）的光降解和细菌的光抑制。与裸 AgNPs 和 TiO2 相比，生物合成的 Ag/TiO2 纳米复合材料具有较强的光还原 MB 和光灭活细菌的催化活性。在 Ag/TiO2 的存在下，只有 40min 的辐照就可以降解 90%的 MB。相比之下，裸 AgNPs 和 TiO2 分别在 100min 以上的辐照下，MB 的降解率不到 30%和 80%。同样，Ag/TiO2 对大肠杆菌和铜绿假单胞菌具有很强的光抑制效率。辐照的 Ag/TiO2 纳米复合材料对大肠杆菌和铜绿假单胞菌的抑菌圈直径分别为 19mm 和 17mm，是黑暗中的两倍。纳米复合材料具有如此高的光催化活性可能是由于 AgNPs 高度修饰在 TiO2 表面。
