Journal of Sol-Gel Science and Technology

, Volume 83, Issue 1, pp 132–142

Surface engineering of TiO2-MWCNT nanocomposites towards tuning of functionalities and minimizing toxicity

  • Mojca Božič
  • Irena Ban
  • Silvo Hribernik
  • Darinka Fakin
  • Karin Stana Kleinschek
Original Paper: Nano-structured materials (particles, fibers, colloids, composites, etc.)
  • 85 Downloads

Abstract

Multiwall carbon nanotubes were coupled with titanium dioxide (in different mole ratios of titanium and carbon) at the nano-scale, using a simple sonochemical and calcination process. The titanium dioxide-multiwall carbon nanotubes nanocomposites were for the first time surface modified with an innovative biotechnology-based reaction by using laccase to activate and covalently graft gallic acid dimers/oligomers/polymers on the nanocomposite surface in order to impart new functionalities and to minimize the nanocomposites’ toxicity. Structure of the titanium dioxide-multiwall carbon nanotubes, before and after surface modification, was investigated with X-ray powder diffraction, infrared, and UV-visible diffuse reflectance spectroscopy analysis, and scanning electron microscopy. The results indicated preferential formation of anatase titanium dioxide on one hand and covalent grafting of gallic acid dimers/oligomers/polymers functionalities on the nanocomposite surface, on the other. After modification, the antioxidant activity was analyzed using 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and photocatalytic activity toward the liquid-phase degradation of methylene blue in aqueous solution under both UV and visible light irradiation. Up to 98% antioxidant activity of the surface modified nanocomposites was established after 24 h of incubation, whereas non-modified nanocomposite induced the formation of the ABTS•+ radicals. In addition, 1.3-2.8-fold reduction in photocatalytic activity was achieved, depending on the irradiation. Accordingly, the gallic acid dimers/oligomers/polymers modified titanium dioxide-multiwall carbon nanotubes appear to simultaneously exhibit photocatalytic activity with an ability to scavenge free radicals, and can thus be considered as engineered nanoparticles with low toxicity.

Graphical Abstract

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Keywords

TiO2-Carbon Nanotube composites Laccase Gallic acid Surface functionalization Photocatalytic activity Antioxidant activity 

Copyright information

© Springer Science+Business Media New York 2017

Authors and Affiliations

  • Mojca Božič
    • 1
  • Irena Ban
    • 2
  • Silvo Hribernik
    • 1
  • Darinka Fakin
    • 1
  • Karin Stana Kleinschek
    • 1
  1. 1.Institute for Engineering Materials and DesignUniversity of MariborMariborSlovenia
  2. 2.Faculty of Chemistry and Chemical EngineeringUniversity of MariborMariborSlovenia

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