Enhancement of UV-assisted photo-Fenton degradation of reactive orange 4 using TiO2-P25 nanoparticles (original) (raw)
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Enhanced heterogeneous ferrioxalate photo-fenton degradation of reactive orange 4 by solar light
Solar Energy Materials and Solar Cells, 2005
A combined homogeneous and heterogeneous photocatalytic decolourisation and degradation of a chlorotriazine Reactive azo dye Reactive Orange 4 (RO4) have been carried out using ferrous sulphate/ ferrioxalate with H 2 O 2 and TiO 2-P25 particles. Solar/ferrous/H 2 O 2 /TiO 2-P25 and solar/ferrioxalate/H 2 O 2 /TiO 2-P25 processes are found to be more efficient than the individual photo-Fenton and solar/TiO 2-P25 processes. A comparison of these two processes with UV/ferrous/H 2 O 2 /TiO 2-P25 and UV/ferrioxalate/H 2 O 2 /TiO 2-P25 reveals that ferrioxalate is more efficient in solar light whereas ferrous ion is more efficient in UV light. The experimental parameters such as pH, initial H 2 O 2 , Fe 2+ , ferrioxalate and TiO 2-P25 concentration strongly influenced the dye removal rate in solar processes. The optimum operating conditions of these two combined processes are reported.
Photocatalytic decolourisation and degradation of Reactive Orange 4 by TiO-UV process
Dyes and Pigments, 2006
The photocatalytic decolourisation and degradation of an azo dye Reactive Orange 4 (RO4) in aqueous solution with TiO 2-P25 (Degussa) as photocatalyst in slurry form has been carried out using UV-A light (365 nm). There is a significant difference in adsorption of dye on TiO 2 surface with the change in the solution pH. The effect of various parameters such as catalyst loading, pH and initial concentration of the dye on decolourisation and degradation have been determined. The dye is decolourised in 80 min and completely degraded in 180 min under optimum conditions. The degradation was strongly enhanced in the presence of electron acceptors such as H 2 O 2 , (NH 4) 2 S 2 O 8 and KBrO 3. The photodecolourisation and degradation kinetics are discussed in terms of LangmuireHinshelwood kinetic model. The degradation intermediates were analysed by GCeMS technique.
Journal of Electroanalytical Chemistry, 2010
Treatment of a dye solution containing C.I. Acid Red 17 (AR17) by photoelectro-Fenton (PEF) combined with photocatalytic process was studied. Carbon nanotube-polytetrafluoroethylene (CNT-PTFE) electrode was used as cathode. The investigated photocatalyst was Millennium PC-500 TiO 2 with crystallites mean size of 5-10 nm immobilized on non-woven paper. A comparison of electro-Fenton (EF), UV/TiO 2 , PEF and PEF/UV/TiO 2 processes for decolorization of AR17 solution was performed. Results showed that color removal follows the decreasing order: PEF/UV/TiO 2 > PEF > EF > UV/TiO 2. Response surface methodology (RSM) was employed to assess individual and interactive effects of the four main independent parameters in PEF/UV/TiO 2 process. Analysis of variance (ANOVA) showed a high coefficient of determination value (R 2 = 0.978) and satisfactory prediction second-order regression. The optimum initial amount of Fe(III), initial dye concentration, reaction time and applied current were found to be 0.2 mM, 15 mg/L, 36 min and 100 mA, respectively. This study clearly showed that RSM was one of the suitable methods to optimize the operating conditions. Graphical response surface and contour plots were used to locate the optimum point.
Decolourisation of Reactive Orange 4 by Fenton and photo-Fenton oxidation technology
Dyes and Pigments, 2004
The photochemical decolourisation of chlorotriazine reactive azo dye Reactive Orange 4 (RO4) has been carried out by Fenton and photo-Fenton processes. The effects of solution pH, applied H 2 O 2 , Fe 2C dose, UV light intensity have been studied. The increase of initial dye concentration decrease the removal rate. Under optimum conditions the photo-Fenton process is found to be more efficient than Fenton process. About 2% of colour resurgens was observed at the end of the reaction.
Effect of Tio 2 Concentration on Photocatalytic Degradation of Reactive Orange 16 Dye ( Ro 16 ) 1
2014
Organic contaminants from industrial and/or domestic effluents may be harmful to humans directly or indirectly by degrading the quality of the environment. Consequently these contaminants must be reduced to levels that are not harmful to humans and the environment before disposal. Among the available chemical methods heterogeneous photocatalytic oxidation has been found particularly to be effective in removal of large number of persistent organics in water. Degradation of the organics was achieved by exposing synthetic effluents to UV light in a photocatalytic reactor in a dark compartment in the presence of catalyst. The degradation of RO16 was conducted at pH 5.5, 24 hr, 294 K and lamp power of 200 W. RO16 was prepared in 200 ml dye solution with concentrations of 20, 40 and 60 mg/L and the degradation took place in presence of TiO2 at concentrations of (0.5-4.0) g/L. While photolysis (in absence of TiO2) was found to have no effect on the degradation of RO16, photocatalysis (in presence of TiO2 catalyst) degraded the dye to 0.4 mg/L.
Optik, 2017
The study describes a new advanced oxidation process: heterogeneous photofenton using a local cheap natural clay as a photocatalyst under a renewable sources of irradiation which is the sun. The selected contaminant Methyl Orange (MO) is an azoïque dye very used in dyeing and printing textiles (textile industries) and often rejected into the aquatic environment. Local clay is characterized by XRD, XR fluorescence, SEM and UV-visible spectrometry in order to determine the gap energy of the clay. The photodegradation process was studied monitoring the change in concentration of organic dye stuff employing UV spectroscopic analysis technique as a function of irradiation time. The degradation was investigated using various parameters such as initials pH, catalyst concentration, concentration of organic dye stuffs. The results indicate that the photodegradation rate of MO clearly increased in the presence of clay when compared with the direct photolysis for a concentration of substrate of 10-4 mol/L, the optimal conditions for a better degradation were obtained for ([clay] = 1 g/L and pH= 3 in the presence of [oxalic acid]=10-2 M).
2023
Effluents resulting from the frequent use of industrial azo dyes in textile operations have posed great toxicological impacts on man and the environment. The limitations of conventional treatment infrastructure necessitate the use of rapid Fenton-mediated catalytic systematic process to tackle the attendant treatment limitations. The study applied in situ Fenton-mediation process with constructed low power UV-LED reactor for rapid catalytic treatment of dye-laden effluent using enhanced acid and alkali TiO 2-nanoparticles (Nps) (1-5%, i.e. 1-5 M) at definite experimental conditions, respectively. A comprehensive instrumental study was done to access the morphological, functional and elemental constituents of these nanocatalysts. The performance of the respective catalyst was evaluated using methylene blue (MB) dye at definite experimental conditions of pH, dosage, concentration and irradiation time. The results revealed a mesoporous structural nanocatalyst with increasing surface area after enhanced modification. The optimal experimental conditions of pH and concentration were recorded as 5 and 10 mg/L, respectively; while the most efficient nanocatalyst was 3 wt% alkali-modified TiO 2 (3% Ak-TiO 2) having a degradation efficiency of 89.15% at 90 min of irradiation using 50 mg dosage in contrast to higher irradiation time and catalyst dosage for other catalysts.
Environmental Technology & Innovation, 2018
The photocatalytic degradation of a model azo dye acid orange 7 (AO7) by Fe 3+-doped TiO 2 nanocatalyst has been studied under UV, Visible (λ > 400 nm) and solar light irradiation. The role of hydrogen peroxide to enhance the catalyst's efficiency was examined. The reaction pathway of complete mineralization was investigated by monitoring the temporal evolution of reaction intermediates and low molecular weight organic acids (LMWOA) as final products in solution. These LMWOAs are oxidized eventually to inorganic ions such a nitrate, sulfate, oxalate etc, which are confirmed using GC-MS, UV-Vis and Ion Chromatographic analyses. The optimized condition of photocatalytic degradation were obtained for degradation under different light source. The Fe 3+-doped TiO 2 showed high dye degradation efficiency under both UV (100%), visible (100%) and solar light (90%) which distinguishes Fe 3+-doped TiO 2 from materials in literature that are only efficient in particular light source for dye degradation. Furthermore, the Fe 3+ doped titania photocatlysts are stable and can maintain performance upto 6 recycle use. Reaction kinetics for UV and solar light induced degradation followed first order reaction whereas visible light degradation followed a zero-order reaction.
Photocatalytic Degradation of Two Commercial Reactive Dyes in Aqueous Phase Using Nanophotocatalysts
Nanoscale Research Letters, 2009
This study involves the photocatalytic degradation of Reactive Black 5 (RB5) and Reactive Orange 4 (RO4) dyes, employing heterogeneous photocatalytic process. Photocatalytic activity of different semiconductors such as titanium dioxide (TiO2) and zinc oxide (ZnO) has been investigated. An attempt has been made to study the effect of process parameters through amount of catalyst, concentration of dye, and pH on photocatalytic degradation of RB5 and RO4. The experiments were carried out by varying pH (3–11), amount of catalyst (0.25–1.5 g/L), and initial concentration of dye (10–100 mg/L). The optimum catalyst dose was found to be 1.25 and 1 g/L for RB5 and RO4, respectively. In the case of RB5, maximum rate of decolorization was observed in acidic medium at pH 4, whereas the decolorization of RO4 reached maximum in basic region at pH 11. The performance of photocatalytic system employing ZnO/UV light was observed to be better than TiO2/UV system. The complete decolorization of RB5 was observed after 7 min with ZnO, whereas with TiO2, only 75% dye degraded in 7 min. In the case of RO4, 92 and 62% decolorization was noticed in the same duration.