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Research article - Peer-reviewed, 2017

Tailoring bifunctional hybrid organic-inorganic nanoadsorbents by the choice of functional layer composition probed by adsorption of Cu2+ ions

Tomina, Veronika V.; Melnyk, Inna; Zub, Yuriy L.; Kareiva, Aivaras; Vaclavikova, Miroslava; Seisenbaeva, Gulaim; Kessler, Vadim

Abstract

Spherical silica particles with bifunctional ( Si(CH2)(3)NH2/ SiCH3, Si(CH2)(3)NH2/ Si(CH2)(2)(CF2)(5)CF3) surface layers were produced by a one-step approach using a modified Stober method in three-component alkoxysilane systems, resulting in greatly increased contents of functional components. The content of functional groups and thermal stability of the surface layers were analyzed by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, and C-13 and Si-29 solid-state NMR spectroscopy revealing their composition and organization. The fine chemical structure of the surface in the produced hybrid adsorbent particles and the ligand distribution were further investigated by electron paramagnetic resonance (EPR) and electron spectroscopy of diffuse reflectance (ESDR) spectroscopy using Cu2+ ion coordination as a probe. The composition and structure of the emerging surface complexes were determined and used to provide an insight into the molecular structure of the surfaces. It was demonstrated that the introduction of short hydrophobic (methyl) groups improves the kinetic characteristics of the samples during the sorption of copper(II) ions and promotes fixation of aminopropyl groups on the surface of silica microspheres. The introduction of long hydrophobic (perfluoroctyl) groups changes the nature of the surface, where they are arranged in alternately hydrophobic/hydrophilic patches. This makes the aminopropyl groups huddled and less active in the sorption of metal cations. The size and aggregation/morphology of obtained particles was optimized controlling the synthesis conditions, such as concentrations of reactants, basicity of the medium, and the process temperature.

Keywords

copper(II) ions; methyl groups; N- and F-containing functional groups; silica nanospheres; sol-gel processes; sorption; surface chemistry

Published in

Beilstein Journal of Nanotechnology
2017, Volume: 8, pages: 334-347
Publisher: BEILSTEIN-INSTITUT

      SLU Authors

    • Seisenbaeva, Gulaim

      • The Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences
      • Kessler, Vadim

        • The Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences

      UKÄ Subject classification

      Materials Chemistry
      Nano-technology
      Other Environmental Engineering

      Publication identifier

      DOI: https://doi.org/10.3762/bjnano.8.36

      Permanent link to this page (URI)

      https://res.slu.se/id/publ/80506