Adsorption of the diazo dye Direct Red 23 onto a zinc oxide surface: A spectroscopic study

Lucilha, Adriana Campano; Bonancêa, Carlos Eduardo; Barreto, Wagner José; Takashima, Keiko

doi:10.1016/j.saa.2009.10.046

Cited by 33 publications

(15 citation statements)

References 13 publications

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“…The pure PPV sample was made with the 1:1 mol/mol proportion between PTHT and DBS (sodium dodecylbenzenesulfonate) [19]. The assignments of the most important Raman peaks are shown in Table 1 [22][23][24]. The peaks at 1284 and 1496 cm -1 are exclusive from the dye, since the naphthalene group and the C-N bound are only present in Reactive Black 5's structure.…”

Section: Resultsmentioning

confidence: 99%

Influence of TiO2 nanoparticles on the optical and structural properties of PPV thin films converted at low temperatures

Rostirolla¹,

Laureto²,

Silva³

et al. 2013

Express Polym. Lett.

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Abstract. In this work we studied the optical properties of poly(p-phenylene vinylene) (PPV) produced by the thermal conversion of a precursor polymer blended with a synthetic dye (Reactive Black 5). The production of PPV by this method decreases the overall time and cost of the process. We observed that the introduction of the dye resulted in an additional absorbance band near 550-700 nm, which can be beneficial to the photon harvesting capacity of the polymer if it is used as the donor material in a photovoltaic device. We studied how the optical and structures properties of this blend change when different quantities of TiO 2 nanoparticles are introduced. For that, thin films were produced by the cast deposition of pre-PPV:dye:TiO 2 . The scanning electronic microscopic images showed that the inorganic semiconductor form large agglomerates of approximately 200 nm, indicating a very rough surface where the dye can be adsorbed. The analysis of photoluminescence and Raman peaks indicated a reduction of the mean conjugation length of the polymer chains in the presence of TiO 2 nanoparticles.

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Section: Resultsmentioning

confidence: 99%

Influence of TiO2 nanoparticles on the optical and structural properties of PPV thin films converted at low temperatures

Rostirolla¹,

Laureto²,

Silva³

et al. 2013

Express Polym. Lett.

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“…All the reactants were of analytical purity and used without previous purification as zinc oxide (ZnO, Nuclear, PA), hexa-hydrated zinc nitrate (Zn(NO 3 14 was a gift from A. Chimical. All the solutions were prepared using purified water (Elga USF CE).…”

Section: Methodsmentioning

confidence: 99%

ZnO AND Ag-ZnO CRYSTALS: SYNTHESIS, CHARACTERIZATION, AND APPLICATION IN HETEROGENEOUS PHOTOCATALYSIS

et al. 2016

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Recebido em 28/07/2015; aceito em 22/12/2015; publicado na web em 11/03/2016ZnO and Ag-ZnO were synthesized in a simple and efficient manner by thermal decomposition of zinc oxalate and silver/zinc mixed oxalate. The influence of the addition of metallic silver on ZnO particles and the effect of temperature in the thermal treatment were investigated. The samples were characterized by thermogravimetric analysis, Raman, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, specific surface area (Brunauer-Emmett-Teller) and diffuse reflectance spectroscopy. The photocatalytic activity of these materials in the decolorization of direct red 23 diazo dye was studied. The complete conversion into oxides from oxalates at lower temperatures was determinant in the photocatalytic efficiency of both the oxides. The presence of silver in zinc oxide, treated at 400 °C, more than doubled the rate constant of diazo dye decolorization (6.87×10-3 min -1) with respect to ZnO, treated at 600 °C, resulting in 3.07×10 -3 min -1 under UV irradiation at 30 °C.

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“…Our research group found similar behavior when direct red 23 diazo dye decolorization was also mediated by ZnO, resulting in reaction orders respectively equal to 0.6 and 2.9. 19 This behavior may be occurred, unlikely from TiO 2 , because the ZnO particles do not agglomerate even in higher concentrations, acquiring colloidal or nanoparticles characteristics, causing change in the reaction order. Therefore, the small particles of ZnO allow the radiation permeation in all the directions of the suspension.…”

Section: Figure 1 Structural Formula Of the Azo Dyes (A) Direct Oranmentioning

confidence: 99%

“…[15][16][17][18] On the other hand, the decolorization rate constant of direct red 23 diazo dye enhanced when the semiconductor concentration was increased from 1.0 to 7.0 g L -1 giving a positive inflection in 5.0 g L -1 , mediated by zinc oxide at 30 °C. 19 In general, the rate constant of the azo dye decolorization increases until a certain TiO 2 concentration and decreases due to the agglomeration of these particles, hindering the radiation passage. Considering the results to the DR23 decolorization in ZnO medium 19 and the difference with respect to TiO 2 , [20][21][22] we investigated the unusual kinetic behavior in ZnO based on photocatalysis by comparing the decolorization kinetic using ZnO and TiO 2 in a wide range of concentrations.…”

Section: Introductionmentioning

confidence: 99%

“…19 In general, the rate constant of the azo dye decolorization increases until a certain TiO 2 concentration and decreases due to the agglomeration of these particles, hindering the radiation passage. Considering the results to the DR23 decolorization in ZnO medium 19 and the difference with respect to TiO 2 , [20][21][22] we investigated the unusual kinetic behavior in ZnO based on photocatalysis by comparing the decolorization kinetic using ZnO and TiO 2 in a wide range of concentrations. Thus, we studied the decolorization of three monoazo dyes (acid orange 7, direct orange 34, and methyl orange), one diazo dye (direct yellow 86) and one tetraazo dye (direct red 80) (Figure 1) -5 mol L -1 (DR80).…”

Section: Introductionmentioning

confidence: 99%

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Kinetic Behavior of Some Azo Dyes Decolorization by Variation of Zinc Oxide and Titanium Dioxide Concentrations

Silva¹,

Monezi²,

Neto³

et al. 2017

Quim. Nova

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publicado na web em 12/12/2017The decolorization of three monoazo dyes (acid orange 7, direct orange 34, and methyl orange), one diazo dye (direct yellow 86) and one tetraazo dye (direct red 80) were mediated by n-type semiconductors as ZnO and TiO 2 under pseudo-first order conditions at 30 ºC. The decolorization rate constants of these azo dyes were determined, varying the semiconductor concentration for the majority of them from 1.0 to 10.0 g L -1. In general, the highest rate constants were displayed for ZnO. This work elucidates that the decolorization capacity depends on the charge, structure, and adsorption of the azo dye on the semiconductor surface as well as the agglomeration of the photocatalyst particles.

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Adsorption of the diazo dye Direct Red 23 onto a zinc oxide surface: A spectroscopic study

Cited by 33 publications

References 13 publications

Influence of TiO2 nanoparticles on the optical and structural properties of PPV thin films converted at low temperatures

Influence of TiO2 nanoparticles on the optical and structural properties of PPV thin films converted at low temperatures

ZnO AND Ag-ZnO CRYSTALS: SYNTHESIS, CHARACTERIZATION, AND APPLICATION IN HETEROGENEOUS PHOTOCATALYSIS

Kinetic Behavior of Some Azo Dyes Decolorization by Variation of Zinc Oxide and Titanium Dioxide Concentrations

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