A Kinetic Study on Photocatalytic Oxidation of Phenol in Water by Silica-Dispersed Titania Nanoparticles

Ding, Zhe; Lu, Gao Qing; Greenfield, P. F.

doi:10.1006/jcis.2000.7154

Cited by 51 publications

(23 citation statements)

References 23 publications

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“…In this case, it is possible to confirm the general behaviour of the composite materials reported by Baek et al Moreover, a few works in the literature have reported that TiO 2 /SiO 2 nanocomposites resulted to be more efficient than TiO 2 alone (Anderson & Bard, 1995;Ding, Lu, & Greenfield, 2000;Xu, Zheng, & Liu, 1999). The increased photoactivity was attributed to the adsorption on the substrate, to the increased specific surface area of the supported TiO 2 , and also to the interaction between titanium oxide and silica (Bellardita et al, 2010).…”

Section: Resultssupporting

confidence: 88%

Photocatalytic degradation of ethylene on mesoporous TiO2/SiO2 nanocomposites: Effects on the ripening of mature green tomatoes

Chiara

Pal

Licciulli

et al. 2015

Biosystems Engineering

107

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Section: Resultssupporting

confidence: 88%

Photocatalytic degradation of ethylene on mesoporous TiO2/SiO2 nanocomposites: Effects on the ripening of mature green tomatoes

Chiara

Pal

Licciulli

et al. 2015

Biosystems Engineering

107

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“…The value of α, γ and K″ was 1.45×10 5 cm −1 , 0.98 and 2.05×10 −13 min −1 [17] , respectively. It was worthwhile to note that the value of K'' was similar to the result of the literature [16,20] . To validate the performance of the model, a figure is plotted for k app vs. f (C ESC ), as shown in Figure 8.…”

Section: Elimination Of the Diffusion On The Degradation Rate Of Momentioning

confidence: 50%

“…The reaction rate for a single TiO 2 particle can be described by the following equation as reported by Ding et al [16] . 1 1…”

Section: Model Developmentmentioning

confidence: 99%

A kinetic model for describing effect of the external surface concentration of TiO2 on the reactivity of eggshell activated carbon supported TiO2 photocatalyst

Zhang

Lei

2007

Chin. Sci. Bull.

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The porous support supported TiO 2 is considered to be the promising photocatalyst due to the fact that it is easily recovered from water and has high capacity to mineralize pollutants. Obviously, the expected structure of this kind of photocatalyst is egg-shell, that is, TiO 2 is mainly on the external surface of the porous support. The reactivity of the supported photocatalyst strongly depends on the concentration of TiO 2 on the external surface of the porous support. In this study, a kinetic model was developed to describe the effect of the external surface concentration of TiO 2 (CESC) on the reactivity of egg-shell activated carbon (AC) supported TiO 2 photocatalysts. It was found that the obtained model precisely described the effect of CESC, on the reactivity of TiO 2 /AC photocatalysts. This study can be used to deeply understand the performance of TiO 2 /AC catalysts and to provide valuable information on designing efficient supported TiO 2 photocatalysts.supported catalysts, kinetic model, egg-shellOver the past few decades, the scientific and engineering interest in the application of heterogeneous photocatalysis by using TiO 2 powder for the decomposition of organic hazardous materials in water has grown exponentially [1] . However, there are some drawbacks of the practical use of the powder TiO 2 during the photocatalytic process [2] : (1) separation of powder TiO 2 from water is difficult; (2) the suspended powder TiO 2 tends to aggregate especially at high concentrations [3] . Therefore, much attention has been paid to the development of supported TiO 2 catalysts in order to solve these problems. A considerable volume of literature has been published on the effect of the characteristics of the supported TiO 2 photocatalysts, such as crystal structure [4] , crystal size [5][6][7] , TiO 2 loading [8,9] , specific surface area [6] , thickness of film [10] and concentration on the surface of the support (for porous supports) [11,12] on their reactivity to obtain the best photocatalyst or optimize the operation parameters of the photocatalyst preparation process.As we know, the catalyst supports such as zeolite, activated carbon, Al 2 O 3 and so on, were commonly semitransparent or opaque. Obviously, only TiO 2 on the external surface of the support can be excited by light and induce the photocatalytic reaction, so the concentration of TiO 2 on the external surface of the support is a very important parameter of the supported TiO 2 photocatalyst [7][8][9]11,12] . In our studies [7,9,11,12] , it was found that the optimal structure of the supported photocatalysts was "egg-shell", that is, TiO 2 was mainly concentrated on Abbreviations: R 1 , concentration of the pollutant during degradation; I, illumination intensity; K, reaction rate constant; s, the surface area of a TiO 2 particle; α, averaged absorption coefficient; γ, shape factor; R, dimension of the TiO 2 particle; I 0 , illumination intensity reaching the wall of the photoreactor; n, number of TiO 2 particles towards the lamp; z, thickness of th...

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“…On the other hand, Jung and Park [20] reported that PCD of trichloroethylene, a neutral substrate, was also accelerated on Si-TiO 2 and ascribed this to the enhanced surface OH group density and reduced bulk defects. The addition of silica to titania prevented the agglomeration of nano-sized anatase particles while producing higher surface area and higher photoreactivity for phenol degradation [21]. In a similar context, Si-TiO 2 showed better photoactivity for degrading ethylene [5] and cyanide [22].…”

Section: Introductionmentioning

confidence: 96%

Enhanced photocatalytic degradation of tetramethylammonium on silica-loaded titania

2005

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Photocatalytic degradation (PCD) of tetramethylammonium (TMA) in water was studied using both pure TiO 2 and silica-loaded TiO 2 (Si-TiO 2 ). Use of Si-TiO 2 catalyst prepared from commercial TiO 2 powder by a simple method developed in this work enhanced the PCD rate of TMA considerably. The Si/Ti atomic ratio of 18% was found to be an optimum in photoactivity and the calcined sample was more efficient than the uncalcined one. Several factors were noted to be responsible for the higher photoefficiency of Si-TiO 2 catalyst. Si-TiO 2 calcined at 700°C did not show any sign of change in the crystalline structure from that of uncalcined pure TiO 2 . The increased thermal stability of Si-TiO 2 enabled the bulk defects to be removed at high temperatures without forming the inactive rutile phase, which may partly contribute to the higher photoactivity. The most outstanding characteristics of Si-TiO 2 is its surface charge modification. Loading silica on to a titania surface made the surface charge highly negative, which was confirmed by zeta potential measurements. The enhanced electrostatic attraction of cationic TMA onto the negatively charged Si-TiO 2 surface seems to be the main reason for the enhanced photoactivity of Si-TiO 2 . As a result of this surface charge change, the TMA PCD rate with Si-TiO 2 exhibited a maximum around pH 7 whereas the PCD with pure TiO 2 was minimized at pH 7. The X-ray photoelectron spectroscopic analysis showed the formation of SiO x on the TiO 2 surface but the diffuse reflectance UV spectra indicated no significant difference in the band gap transition between pure TiO 2 and Si-TiO 2 . In addition, the diffuse reflectance IR spectra showed the presence of more surface OH groups on Si-TiO 2 than on pure TiO 2 , which may also contribute to the higher photoactivity of Si-TiO 2 through generating more OH radicals upon UV illumination.

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A Kinetic Study on Photocatalytic Oxidation of Phenol in Water by Silica-Dispersed Titania Nanoparticles

Cited by 51 publications

References 23 publications

Photocatalytic degradation of ethylene on mesoporous TiO2/SiO2 nanocomposites: Effects on the ripening of mature green tomatoes

Photocatalytic degradation of ethylene on mesoporous TiO2/SiO2 nanocomposites: Effects on the ripening of mature green tomatoes

A kinetic model for describing effect of the external surface concentration of TiO2 on the reactivity of eggshell activated carbon supported TiO2 photocatalyst

Enhanced photocatalytic degradation of tetramethylammonium on silica-loaded titania

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