Photocatalytic degradation of contaminants of concern with composite NF-TiO2 films under visible and solar light

Environ Sci Pollut Res Int. 2013 Jun;20(6):3582-91. doi: 10.1007/s11356-013-1550-z. Epub 2013 Feb 24.

Abstract

This study reports the synthesis and characterization of composite nitrogen and fluorine co-doped titanium dioxide (NF-TiO(2)) for the removal of contaminants of concern in wastewater under visible and solar light. Monodisperse anatase TiO(2) nanoparticles of different sizes and Evonik P25 were assembled to immobilized NF-TiO(2) by direct incorporation into the sol-gel or by the layer-by-layer technique. The composite films were characterized with X-ray diffraction, high-resolution transmission electron microscopy, environmental scanning electron microscopy, and porosimetry analysis. The photocatalytic degradation of atrazine, carbamazepine, and caffeine was evaluated in a synthetic water solution and in an effluent from a hybrid biological concentrator reactor (BCR). Minor aggregation and improved distribution of monodisperse titania particles was obtained with NF-TiO(2)-monodisperse (10 and 50 nm) from the layer-by-layer technique than with NF-TiO(2) +monodisperse TiO(2) (300 nm) directly incorporated into the sol. The photocatalysts synthesized with the layer-by-layer method achieved significantly higher degradation rates in contrast with NF-TiO(2)-monodisperse titania (300 nm) and slightly faster values when compared with NF-TiO(2)-P25. Using NF-TiO(2) layer-by-layer with monodisperse TiO(2) (50 nm) under solar light irradiation, the respective degradation rates in synthetic water and BCR effluent were 14.6 and 9.5 × 10(-3) min(-1) for caffeine, 12.5 and 9.0 × 10(-3) min(-1) for carbamazepine, and 10.9 and 5.8 × 10(-3) min(-1) for atrazine. These results suggest that the layer-by-layer technique is a promising method for the synthesis of composite TiO(2)-based films compared to the direct addition of nanoparticles into the sol.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Atrazine / metabolism
  • Caffeine / metabolism
  • Carbamazepine / metabolism
  • Catalysis
  • Microscopy, Electron, Scanning
  • Microscopy, Electron, Transmission
  • Nanoparticles / chemistry
  • Nitrogen / chemistry*
  • Photolysis*
  • Sunlight*
  • Titanium / chemistry
  • Wastewater / chemistry
  • Water Pollutants, Chemical / chemistry
  • X-Ray Diffraction

Substances

  • Waste Water
  • Water Pollutants, Chemical
  • titanium dioxide
  • Carbamazepine
  • Caffeine
  • Titanium
  • Nitrogen
  • Atrazine