Photocatalytic Degradation of Azo Dyes Using Au:TiO2, γ-Fe2O3:TiO2 Functional Nanosystems
Abstract:We report photocatalytic degradation studies on Navy Blue HE2R (NB) dye on significant details as a representative from the class of azo dyes using functional nanosystems specifically designed to allow a strong photocatalytic activity. A modified sol–gel route was employed to synthesize Au and γ-Fe2O3 modified TiO2 nanoparticles (NPs) at low temperature. The attachment strategy is better because it allows clear surface of TiO2 to remain open for photo-catalysis. X-ray diffraction, Raman and UV-VIS spectroscopy studies showed the presence of gold and iron oxide phases along-with the anatase TiO2 phase. TEM studies showed TiO2 nanocomposite particles of size ∼10–12 nm. A detailed investigation on heterogeneous photocatalytic performance for Navy Blue HE2R dye was done using the as-synthesized catalysts Au:TiO2 and γ-Fe2O3:TiO2 in aqueous suspension under 8 W low-pressure mercury vapour lamp irradiation. Also, the photocatalytic degradation of Amranth and Orange G azo dyes were studied. The surface modified TiO2 NPs showed significantly improved photocatalytic activity as compared to pure TiO2. Exposure of the dye to the UV light in the presence of pure and gold NPs attached TiO2 catalysts caused dye degradation of about ∼20% and ∼80%, respectively, in the first couple of hours. In the presence of γ-Fe2O3 NPs attached TiO2, a remarkable ∼95% degradation of the azo dye was observed only in the first 15 min of UV exposure. The process parameters for the optimum catalytic activity are established which lead to a complete decoloration and substantial dye degradation, supported by the values of the Chemical Oxygen Demand (COD) ∼93% and Total Organic Carbon (TOC) ∼65% of the treated dye solution after 5 hours on the employment of the UV/Au:TiO2/H2O2 photocatalytic process.
Document Type: Research Article
Publication date: 2012-02-01
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- Journal for Nanoscience and Nanotechnology (JNN) is an international and multidisciplinary peer-reviewed journal with a wide-ranging coverage, consolidating research activities in all areas of nanoscience and nanotechnology into a single and unique reference source. JNN is the first cross-disciplinary journal to publish original full research articles, rapid communications of important new scientific and technological findings, timely state-of-the-art reviews with author's photo and short biography, and current research news encompassing the fundamental and applied research in all disciplines of science, engineering and medicine.
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