Titanium dioxide based nanomaterials for photocatalytic water treatment
Levchuk, Irina (2016-08-05)
Väitöskirja
Levchuk, Irina
05.08.2016
Lappeenranta University of Technology
Acta Universitatis Lappeenrantaensis
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-265-978-1
https://urn.fi/URN:ISBN:978-952-265-978-1
Tiivistelmä
Water treatment using photocatalysis has gained extensive attention in recent years.
Photocatalysis is promising technology from green chemistry point of view. The most
widely studied and used photocatalyst for decomposition of pollutants in water under
ultraviolet irradiation is TiO2 because it is not toxic, relatively cheap and highly active
in various reactions.
Within this thesis unmodified and modified TiO2 materials (powders and thin films)
were prepared. Physico-chemical properties of photocatalytic materials were
characterized with UV-visible spectroscopy, scanning electron microscopy (SEM),
transmission electron microscopy (TEM), X-ray photoelectron spectrometry (XPS),
inductively coupled plasma optical emission spectroscopy (ICP-OES), ellipsometry,
time-of-flight secondary ion mass spectrometry (ToF-SIMS), Raman spectroscopy,
goniometry, diffuse reflectance measurements, thermogravimetric analysis (TGA) and
nitrogen adsorption/desorption. Photocatalytic activity of prepared samples in aqueous
environment was tested using model compounds such as phenol, formic acid and
metazachlor. Also purification of real pulp and paper wastewater effluent was studied.
Concentration of chosen pollutants was measured with high pressure liquid
chromatography (HPLC). Mineralization and oxidation of organic contaminants were
monitored with total organic carbon (TOC) and chemical oxygen demand (COD)
analysis. Titanium dioxide powders prepared via sol-gel method and doped with
dysprosium and praseodymium were photocatalytically active for decomposition of
metazachlor. The highest degradation rate of metazachlor was observed when Pr-TiO2
treated at 450ºC (8h) was used. The photocatalytic LED-based treatment of wastewater
effluent from plywood mill using commercially available TiO2 was demonstrated to be
promising post-treatment method (72% of COD and 60% of TOC was decreased after
60 min of irradiation). The TiO2 coatings prepared by atomic layer deposition technique
on aluminium foam were photocatalytically active for degradation of formic and phenol,
however suppression of activity was observed. Photocatalytic activity of TiO2/SiO2
films doped with gold bipyramid-like nanoparticles was about two times higher than
reference, which was not the case when gold nanospheres were used.
Photocatalysis is promising technology from green chemistry point of view. The most
widely studied and used photocatalyst for decomposition of pollutants in water under
ultraviolet irradiation is TiO2 because it is not toxic, relatively cheap and highly active
in various reactions.
Within this thesis unmodified and modified TiO2 materials (powders and thin films)
were prepared. Physico-chemical properties of photocatalytic materials were
characterized with UV-visible spectroscopy, scanning electron microscopy (SEM),
transmission electron microscopy (TEM), X-ray photoelectron spectrometry (XPS),
inductively coupled plasma optical emission spectroscopy (ICP-OES), ellipsometry,
time-of-flight secondary ion mass spectrometry (ToF-SIMS), Raman spectroscopy,
goniometry, diffuse reflectance measurements, thermogravimetric analysis (TGA) and
nitrogen adsorption/desorption. Photocatalytic activity of prepared samples in aqueous
environment was tested using model compounds such as phenol, formic acid and
metazachlor. Also purification of real pulp and paper wastewater effluent was studied.
Concentration of chosen pollutants was measured with high pressure liquid
chromatography (HPLC). Mineralization and oxidation of organic contaminants were
monitored with total organic carbon (TOC) and chemical oxygen demand (COD)
analysis. Titanium dioxide powders prepared via sol-gel method and doped with
dysprosium and praseodymium were photocatalytically active for decomposition of
metazachlor. The highest degradation rate of metazachlor was observed when Pr-TiO2
treated at 450ºC (8h) was used. The photocatalytic LED-based treatment of wastewater
effluent from plywood mill using commercially available TiO2 was demonstrated to be
promising post-treatment method (72% of COD and 60% of TOC was decreased after
60 min of irradiation). The TiO2 coatings prepared by atomic layer deposition technique
on aluminium foam were photocatalytically active for degradation of formic and phenol,
however suppression of activity was observed. Photocatalytic activity of TiO2/SiO2
films doped with gold bipyramid-like nanoparticles was about two times higher than
reference, which was not the case when gold nanospheres were used.
Kokoelmat
- Väitöskirjat [1037]