首页> 外文学位 >文献详情
【6h】

A new green chemistry method based on plant extracts to synthesize gold nanoparticles.

机译:一种基于植物提取物合成金纳米粒子的绿色化学新方法。

获取原文
¥30

摘要

Extraordinary chemical and physical properties exhibited by nanomaterials, as compared to their bulk counterparts, have made the area of nanotechnology a growing realm in the past three decades. It is the nanoscale size (from 1 to 100 nm) and the morphologies of nanomaterials that provide several properties and applications not possible for the same material in the bulk. Magnetic and optical properties, as well as surface reactivity are highly dependent on the size and morphology of the nanomaterial. Diverse nanomaterials are being widely used in molecular diagnostics as well as in medicine, electronic and optical devices. Among the most studied nanomaterials, gold nanoparticles are of special interest due to their multifunctional capabilities. For instance, spherical gold nanoparticles measuring 15-20 nm in diameter have been studied due to their insulin binding properties. Also, thiol functionalized gold nanoparticles between 5 and 30 nm are used in the detection of DNA. Thus, harnessing the shape and size of gold nanoparticles plays an important role in science and technology.The synthesis of gold nanoparticles via the reduction of gold salts, using citrate or other reducing agents, has been widely studied. In recent years, algae, fungi, bacteria, and living plants have been used to reduce trivalent gold (Au3+) to its zero oxidation state (Au 0) forming gold nanoparticles of different sizes and shapes. In addition, plant biomasses have also been studied for their gold-reducing power and nanoparticle formation. Although there is information about the synthesis of the gold nanoparticles by biologically based materials to our knowledge, the study of the use of alfalfa extracts has not been reported. This innovation represents a significant improvement that is an environmentally friendly method that does not use toxic chemicals. Also, the problem of extracting the formed gold nanoparticles from biomaterials is addressed in this research but still remains to be solved.In this work, secondary metabolites were extracted from alfalfa biomass in liquid phase by hot water, isopropanol, and methanol, and used to reduce tetrachloroaurate ion (AuCl4-) for the synthesis of gold nanoparticles. Biosyntheses of gold nanoparticles were performed by mixing 0.75, 1.5 and 3.0 mM Au3+ solutions with each one of the extracts at a ratio of 3:1 respectively, and shaken at room temperature for 1h. Resulting gold colloids were characterized by UV-Vis spectrophotometry and electron microscopy techniques, showing size and morphology dependency on the reaction conditions. Isopropanol alfalfa extracts reacted with Au 3+ produced gold nanoparticles with a size range of 15-60 nm. The most abundant were from 40-50 nm, and the morphologies found were polygons, decahedra and icosahedra. Methanol alfalfa extracts produced monodisperse 50 nm decahedral and icosahedral gold nanoparticles. Lastly, water alfalfa extracts reacted with Au3+ produced triangular, truncated triangular and hexagonal nanoplates with diameters ranging from 500 nm to 4 mum and thicknesses of &sim15-40 nm. The production of gold nanoplates by alfalfa extracts has never been reported before.In order to extract the formed gold nanoparticles from the biomass, physical and chemical extractions were used. For the chemical extraction, NaCl, dilute H2SO4, Triton X and DI water were tested. In these cases, the best results were obtained with DI water, followed by NaCl. The extracted nanoparticles had an absorption band at about 539 nm. For the physical extractions, alfalfa biomass containing gold nanoparticles were exposed to 400°C, 500°C, 550°C and 600°C to recover the gold nanoparticles. X-ray diffractograms taken after pyrolysis of the biomass showed that the recovered nanoparticles kept their crystal structure.
机译:与过去的大量材料相比,纳米材料所展现的非凡的化学和物理特性已经使纳米技术领域成为一个增长的领域。纳米级尺寸(从1到100 nm)和纳米材料的形貌可为同一材料散装提供多种特性和应用。磁性和光学性质以及表面反应性高度取决于纳米材料的尺寸和形态。多样的纳米材料被广泛用于分子诊断以及医学,电子和光学设备。在研究最多的纳米材料中,金纳米颗粒因其多功能功能而备受关注。例如,由于它们的胰岛素结合特性,已经研究了直径为15-20 nm的球形金纳米颗粒。同样,在5和30 nm之间的硫醇官能化的金纳米颗粒也用于DNA的检测。因此,利用金纳米颗粒的形状和大小在科学技术中起着重要的作用。广泛研究了使用柠檬酸盐或其他还原剂通过金盐的还原来合成金纳米颗粒。近年来,藻类,真菌,细菌和有生命的植物已被用于将三价金(Au3 +)还原为零氧化态(Au 0),从而形成不同大小和形状的金纳米颗粒。此外,还研究了植物生物量的降金能力和纳米颗粒形成。尽管据我们所知有关于通过生物基材料合成金纳米颗粒的信息,但尚未报道使用苜蓿提取物的研究。这项创新代表了一项重大改进,它是一种不使用有毒化学物质的环保方法。同样,这项研究解决了从生物材料中提取形成的金纳米颗粒的问题,但仍然有待解决。在这项工作中,通过热水,异丙醇和甲醇从苜蓿生物质中液相提取了次级代谢产物,并将其用于还原四氯金酸根离子(AuCl4-)以合成金纳米颗粒。通过分别将0.75、1.5和3.0 mM Au3 +溶液与每种提取物分别以3:1的比例混合,并在室温下振摇1h,进行金纳米颗粒的生物合成。通过UV-Vis分光光度法和电子显微镜技术对所得的金胶体进行表征,显示出大小和形态对反应条件的依赖性。异丙醇苜蓿提取物与Au 3+反应生成的金纳米粒子的大小范围为15-60 nm。最丰富的是40-50 nm,发现的形态是多边形,十面体和二十面体。甲醇苜蓿提取物可产生单分散的50 nm十面体和二十面体金纳米颗粒。最后,紫花苜蓿提取物与Au3 +反应生成了直径为500 nm至4 mm且厚度为&sim15-40 nm的三角形,截短的三角形和六边形纳米板。紫花苜蓿提取物生产金纳米板的报道从未有过报道。为了从生物质中提取形成的金纳米颗粒,使用了物理和化学提取方法。对于化学提取,测试了NaCl,稀H2SO4,Triton X和DI水。在这些情况下,先用去离子水,再用氯化钠,可获得最佳结果。提取的纳米颗粒在约539nm处具有吸收带。对于物理提取,将包含苜蓿生物质的金纳米颗粒暴露于400°C,500°C,550°C和600°C下以回收金纳米颗粒。生物质热解后拍摄的X射线衍射图表明,回收的纳米粒子保持其晶体结构。

著录项

  • 作者单位

    The University of Texas at El Paso.;

  • 授予单位 The University of Texas at El Paso.;
  • 学科 Chemistry Analytical.Chemistry Inorganic.Nanoscience.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 73 p.
  • 总页数 73
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 H0;
  • 关键词

站内服务
  • 论文查重
  • 论文收录引证报告
  • 文档翻译
  • 文档转换
获取原文

联系方式:18141920177 (微信同号)

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号