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CHEMICAL PROCESSES INVOLVED IN Au(III) BINDING AND BIOREDUCTION BY ALFALFA BIOMASS

机译:苜蓿生物质参与Au(III)结合和生物还原的化学过程

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摘要

Current precious metal recovery technologies that use harsh chemicals may represent a threat to thernenvironment and public health. Thus, there is a necessity to develop environmentally friendly systems tornretrieve precious metals. In previous experiments, dead alfalfa biomass has shown to be efficient for gold(III)rnrecovery. Gold(III) binding to alfalfa biomass is rapid, pH independent, and increases with time and temperature.rnFurthermore, with X-ray absorption spectroscopy, alfalfa was found to reduce gold(III) to gold(0) and producernnanoparticles. Transmission electron micrographs showed nanoparticles of several shapes and sizes. Thernreduction process was also found to be pH, time, and temperature dependent. In order to resolve the mechanismrnof both binding and reduction of gold(III) by alfalfa biomass, further experiments were performed. The effect ofrnchemical modification of the alfalfa biomass on gold(III) binding and reduction was determined. Also, further Xrayrnabsorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopyrnstudies were performed to assess the oxidation state and nearest neighbor of the bound gold as a functionrnof time. The results indicate that gold(III) goes to gold(I) and then to gold(0). Also, EXAFS shows that bindingrnmay occur via a nitrogen or oxygen ligand.
机译:当前使用苛刻化学品的贵金属回收技术可能对环境和公众健康构成威胁。因此,有必要开发一种回收稀有金属的环保系统。在先前的实验中,已证实的苜蓿死生物量对金(III)的回收是有效的。金(III)与苜蓿生物量的结合迅速,不受pH限制且随时间和温度的升高而增加。此外,通过X射线吸收光谱法,发现苜蓿将金(III)还原为金(0)和生产者纳米颗粒。透射电子显微照片显示了几种形状和尺寸的纳米颗粒。还发现还原过程与pH,时间和温度有关。为了解决苜蓿生物量对金(III)的结合和还原的机理,进行了进一步的实验。确定了苜蓿生物量化学修饰对金(III)结合和还原的影响。另外,还进行了进一步的X射线吸收近边缘结构(XANES)和扩展的X射线吸收精细结构(EXAFS)光谱学研究,以评估结合金的氧化态和最邻近原子随时间的变化。结果表明,金(III)变为金(I),然后变为金(0)。同样,EXAFS显示结合可以通过氮或氧配体发生。

著录项

  • 来源
  • 会议地点 Denver CO(US)
  • 作者单位

    Department of Chemistry and Environmental Science and Engineering, PSCI Bldg., University of Texas at El Paso, El Paso, TX 79968, Phone: (915) 747-5359 Fax: (915) 747-5748;

    rnDepartment of Chemistry and Environmental Science and Engineering, PSCI Bldg., University of Texas at El Paso, El Paso, TX 79968, Phone: (915) 747-5359 Fax: (915) 747-5748;

    rnDepartment of Chemistry and Environmental Science and Engineering, PSCI Bldg., University of Texas at El Paso, El Paso, TX 79968, Phone: (915) 747-5359 Fax: (915) 747-5748;

    rnDepartment of Chemistry and Environmental Science and Engineering, PSCI Bldg., University of Texas at El Paso, El Paso, TX 79968, Phone: (915) 747-5359 Fax: (915) 747-5748;

    rnDepartment of Chemistry and Environmental Science and Engineering, PSCI Bldg., University of Texas at El Paso, El Paso, TX 79968, Phone: (915) 747-5359 Fax: (915) 747-5748;

    rnDepartment of Chemistry and Environmental Science and Engineering, PSCI Bldg., University of Texas at El Paso, El Paso, TX 79968, Phone: (915) 747-5359 Fax: (915) 747-5748;

  • 会议组织
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境污染及其防治;
  • 关键词

    XANES; EXAFS; alfalfa; gold; phytofiltration; metal binding; chemical modification;

    机译:XANES; EXAFS;苜蓿;金;植物滤过;金属结合;化学修饰;

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