Pregledni rad
Thermal evolution process, properties and photocatalytic activity of sol-gel derived nanocrystalline anatase in dye degradation process
Iva Minga
; Faculty of chemical engineering and technology, University of Zagreb, Croatia
Stanislav Kurajica
; Faculty of chemical engineering and technology, University of Zagreb, Croatia
Vilko Mandić
; Faculty of chemical engineering and technology, University of Zagreb, Croatia
Sažetak
Nanocrystalline anatase aimed to be used as a photocatalyst for dye degradation processes
in industrial effluents and has been prepared and investigated. Amorphous titania
gel has been prepared using sol–gel process by slow hydrolysis of titanium n–butoxide.
The prepared gel has been investigated using Fourier–Transformed Infra–Red
Spectroscopy (FTIR), Powder X–ray Diffraction (PXRD), Differential Thermal Analysis
(DTA), Thermo–Gravimetric Analysis (TGA), N2
gas adsorption–desorption isotherms
and Diffuse Reflectance UV–Vis Spectroscopy (DRS).
It was determined that the amorphous gel was comprised of non-hydrolyzed butoxy
groups as well as hydroxyl groups bonded to titanium. The thermal evolution of gel is
consisted of five steps: elimination of adsorbed water and butanol in temperature range
between room temperature and 200 °C, decomposition and elimination of butoxy
groups between 200 and 300°C. The crystallization of anatase centered at 404°C, transformation
to rutile starting from 540 °C and oxidation of char and tar above 600°C.
Thermal treatment of gel at 350 °C for 2 h yields with pure nanocrystalline anatase with
average crystallite size of 13.2±0.2 nm, specific surface area of 65.48 m2
g–1 and bandgap,
of 3.24 eV. The preliminary assessment of prepared catalyst photocatalytic activity was
obtained through degradation process of methylene blue dye under UV light and the
99 % degradation of dye took place within 150 min.
Ključne riječi
nanocrystalline anatase; sol-gel; photocatalysis; dyes
Hrčak ID:
154947
URI
Datum izdavanja:
23.12.2015.
Posjeta: 819 *