Original scientific paper
EFFECTS OF CONCENTRATION AND UV RADIATION WAVELENGHTS ON PHOTOLYTIC AND PHOTOCATALYTIC DEGRADATION OF AZO DYES AQUEOUS SOLUTIONS BY SOL-GEL TiO2 FILMS
Veronika Marinović
; Forensic Science Centre “Ivan Vučetić”, Zagreb, Croatia
Davor Ljubas
; Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Croatia
Lidija Ćurković
; Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Croatia
Abstract
The photocatalytic and photolytic degradation of anionic azo dyes Methyl Orange and Congo Red dye aqueous solutions was investigated in glass reactors with/without TiO2 films that were irradiated with UV light. Two nanostructured sol-gel TiO2 films were prepared by means of the dip-coating technique with and without of polyethylene glycol (PEG) as a structure-directing agent. Experiments were carried out by varying the concentration of dyes, TiO2 films and sources of UV radiation. The concentrations of dyes were 0.0125 mmol L-1, 0.025 mmol L-1 and 0.05 mmol L-1; the wavelengths of the incident ultraviolet light were predominantly 254 (UV-C) and 365 nm (UV-A). In the presence of TiO2 film UV-C radiation showed higher degradation efficiency for both dyes than UV-A radiation. Also, UV-C radiation without TiO2 photocatalyst was capable of degrading both dyes, while UV-A radiation alone did not show a potential for dyes degradation. Higher photoactivity showed TiO2 film with addition of PEG.
Keywords
UV radiation; TiO2 film; Congo red dye; Methyl Orange dye; photocatalysis; photolysis
Hrčak ID:
168850
URI
Publication date:
5.11.2016.
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