Texas A&M University-Kingsville, 78363, USA.
Colloids Surf B Biointerfaces. 2010 May 1;77(1):82-9. doi: 10.1016/j.colsurfb.2010.01.010. Epub 2010 Jan 21.
An environmental-friendly procedure for manufacturing silver (Ag) and titania (TiO(2)) nanocomposites in an aqueous solution is presented. This green synthetic approach results in the successful production of nanomaterials with high dispersion and crystallinity. The colloidal suspensions of the nanocomposites composed of metal and ceramic (Ag-TiO(2)) were found to be extremely stable over a prolonged time period. Morphologically, nanocomposites were found to be composed of near-spherical particles that were highly crystalline. The nanocomposites were mono-dispersed with particles varying in size from 20 to 50nm, depending upon nanocomposite solution pH. Indexed metallic nanoscale silver exhibited a face-centered cubic (fcc) crystalline phase structure. Nanocomposite elemental composition studies indicated that the molar ratio of Ag and Ti was approximately 1-20. The binding energies and energy differences of Ag, Ti and O were well-indexed with their associated standard spectra. Nanocomposite optical absorption properties were consistent with noble metal nanoparticles. The zetapotential for the nanocomposites was higher at acidic pH and exhibited an absolute negative charge that apparently inhibited particle agglomeration. Escherichia coli (E. coli), a Gram-negative model microorganism was effectively inactivated using the nanocomposites under visible light at ambient temperature and pressure. The 'green chemistry' derived Ag-TiO(2) composites are applicable for the removal of biological impurities from drinking and underground water supplies. The results of the study indicated that nanocomposites could be specifically designed to prevent growth of bacteria in water.
一种在水溶液中制造银（Ag）和二氧化钛（TiO(2)）纳米复合材料的环保方法。这种绿色合成方法成功地生产出具有高分散性和结晶度的纳米材料。胶体悬浮液中的纳米复合材料由金属和陶瓷（Ag-TiO(2)）组成，在很长一段时间内都非常稳定。形态上，纳米复合材料由近球形颗粒组成，具有高度的结晶性。纳米复合材料呈单分散状态，颗粒尺寸在 20 至 50nm 之间，具体取决于纳米复合材料溶液的 pH 值。指数化的金属纳米级银表现出面心立方（fcc）的晶体相结构。纳米复合材料的元素组成研究表明，Ag 和 Ti 的摩尔比约为 1-20。Ag、Ti 和 O 的结合能和能量差与它们相关的标准光谱很好地吻合。纳米复合材料的光吸收特性与贵金属纳米颗粒一致。纳米复合材料的动电位在酸性 pH 值下较高，并表现出绝对的负电荷，显然抑制了颗粒聚集。大肠杆菌（E. coli），一种革兰氏阴性模型微生物，在环境温度和压力下，在可见光下使用纳米复合材料有效失活。从“绿色化学”衍生而来的 Ag-TiO(2)复合材料可用于去除饮用水和地下水中的生物杂质。研究结果表明，可以专门设计纳米复合材料来防止水中细菌的生长。
