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Интеллектуальная Система Тематического Исследования НАукометрических данных |
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Humic macroligands in the synthesis and stabilization of nanoparticlesтезисы доклада
- Авторы: Perminova I.V., Polyakov A.Yu, Volikov A.B., Lebedev V.A., Shirshin E.A., Fadeev V.V., Sorkina T.A., Pankratov D.A., Veligzhanin A.A., Goodilin E.A.
- Сборник: Abstracts of the Bilateral Russian-Taiwanese Symposium “Polymers as a Basis for Advanced Materials, 17-18 July 2014, Lomonosov MSU
- Тезисы
- Год издания: 2014
- Место издания: Lomonosov MSU, Moscow, Russia
- Аннотация: Humic substances (HS) are natural macroligands with major functionalities presented by carboxylic groups and phenolic moieties. As a result, HS enter redox and complexing interactions with metals mediating their migration and bioavailability in the environment. Recently, it has been revealed that these interactions can also facilitate formation and stabilization of metal-containing nanoparticles in natural waters and soils. Understanding of these processes might shed light on migration and toxicity of nanoparticles released into the environment. On the other side, reproduction of these processes in the lab might open new possibilities for a use of natural macromolecular compounds – humic substances – for synthesis of biocompatible and stabilized nanoparticles. The objectives of this study were to realize humics-assisted synthesis of nanoparticles of different metals, and to study their properties and colloidal stability. Three different metals were used for humics-assisted synthesis of nanoparticles: iron, gold, and silver. In case of iron, we used both reducing and oxidizing conditions that lead to formation of zero-valent iron nanoparticles (nZVI) and iron oxohydroxides – feroxyhyte and lepidocrocite nanoparticles, respectively. A synthesis of feroxyhyte (δ' FeOOH) and lepidocrocite (γ FeOOH) nanoparticles was carried out by precipitation and oxidation of Fe(OH)n2-n + Fe(OH)m3-m suspension directly into aqueous solutions of HS. A synthesis of nZVI was conducted by reduction of ferrous ions with sodium borohydride in the presence of HS. In case of gold and silver, reduction of HAuCl4- and Ag+ in the presence of HS occurred spontaneously, without addition of reducing agents. The study of nanoparticles growth in the presence of HS was conducted using optical spectroscopy methods – dynamic light scattering (DLS), UV-visible absorption, fluorescence spectroscopy, as well as transmission electron microscopy (TEM), X-ray absorption (XANES), and Moessbauer-spectroscopy. It was shown that in the presence of HS, plate-like feroxyhyte NPs with transversal size 20-30 nm and thickness up to 3 nm were formed. The NPs were encapsulated into humic associates composing organo-inorganic composites. In the absence of HS in the reaction mixture, uncontrolled growth of NPs up to submicron sizes (300-400 nm) was observed. It should be specifically noted that the encapsulated NPs of feroxyhyte possessed superparamagnetic properties. During the AuNPs and AgNPs synthesis, the evolution of surface plasmon resonance peak was observed, followed by the HS fluorescence band deformation, which can be attributed to excitation energy transfer in the HS-AuNPs and HS-AgNPs system. Au nanoclusters transformation was also monitored by the relative changes of particle size distribution calculated from DLS data, indicating Au seed aggregates of random complex morphology in the beginning of the synthesis process. This fact was also confirmed using transmission electron microscopy. Similar behavior was observed for AgNPs. The presented results allowed us to conclude on a broad perspectives for a use of natural macroligands – humic substances – for synthesis of nanoparticles and nanomaterials, which can be used in modern environmental, biomedical, and agricultural technologies. Acknowledgement: This research was partially supported by the Russian Foundation for Basic Research grant # 13-04-0185313.
- Добавил в систему: Перминова Ирина Васильевна