Infrared Study of Ozone Adsorption on TiO2 (Anatase)

Bulanin, K. M.; Lavalley, J.C.; Цыганенко, А. А.

doi:10.1021/j100025a034

Cited by 101 publications

(112 citation statements)

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“…So far, the hypothesis of Golodets (1983) has only indirectly and qualitatively been tested: The formation of O atoms after adsorption of O 3 onto TiO 2 at 77 K has been verified by formation of CO 2 after addition of CO to the surface (Bulanin et al, 1995b). Also the release of O 2 has been proven only indirectly, by a pressure increase during the O 3 decomposition process (Hanning-Lee et al, 1996;Thomas et al, 1997), and qualitatively by the assignment of certain bonds in Raman spectra to gaseous O 2 (Li et al, 1998).…”

Section: The Uptake Mechanismmentioning

confidence: 99%

“…According to another FT-IR study of the same group on the interaction between O 3 and a partially hydrated TiO 2 surface (Bulanin et al, 1995b), at least three different types of surface sites for O 3 adsorption can be distinguished: (I) surface sites where O 3 is weakly bound to hydroxyl groups or by physisorption; (II) surface sites with weak Lewis acid character (unsaturated Ti IV ions) where O 3 is chemisorbed but remains intact with distorted geometry; and (III) strong Lewis acid sites where adsorbed O 3 molecules are sufficiently distorted that they dissociate into O 2 and O. O 3 adsorption to surface sites type I is completely reversible, as was shown for O 3 adsorption onto partially hydrated SiO 2 (Bulanin et al, 1994). In the present experiments, if reversible O 3 uptake to OH groups (surface sites type I) had played a role, O 3 desorption after O 3 uptake should have been observable, which was not the case.…”

Section: The Uptake Mechanismmentioning

confidence: 99%

“…Surface sites type II are a weak form of surface sites type III, with the strength and the number of Lewis acid sites increasing with increasing dehydration of the surface (Bulanin et al, 1995b). As type III sites are responsible for O 3 destruc- tion, dehydration of the surface, i.e.…”

Section: The Uptake Mechanismmentioning

confidence: 99%

“…A number of studies have been performed on the adsorption of O 3 onto various mineral oxides, using electron paramagnetic resonance, infrared spectroscopy and kinetic measurement techniques (Dhandapani and Oyama, 1997). The surfaces examined were among others: γ -Al 2 O 3 (Klimovskii et al, 1983;Bulanin et al, 1995a;Thomas et al, 1997), SiO 2 (Bulanin et al, 1994), TiO 2 (Bulanin et al, 1995a(Bulanin et al, , 1995b, CaO (Bulanin et al, 1997) and MgO (Bulanin et al, 1995a;Berlier et al, 2002). A few semi-quanitative studies on the interaction between ozone and authentic mineral dust have been published (Suzuki et al, 1979;Alebic-Juretic et al, 1992;Alebic-Juretic et al, 2000), and initial uptake coefficients for O 3 uptake onto synthetic and authentic minerals have been measured (Michel et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

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Ozone decomposition on Saharan dust: an experimental investigation

2003

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Abstract. The heterogeneous reaction between O 3 and authentic Saharan dust surfaces was investigated in a Knudsen reactor at ≈ 296 K. O 3 was destroyed on the dust surface and O 2 was formed with conversion efficiencies of 1.0 and 1.3 molecules O 2 per O 3 molecule destroyed for unheated and heated samples, respectively. No O 3 desorbed from exposed dust samples, showing that the uptake was irreversible. The uptake coefficients for the irreversible destruction of O 3 on (unheated) Saharan dust surfaces depended on the O 3 concentration and varied between 3.5 × 10 −4 and 5.5 × 10 −6 for the initial uptake coefficient (γ 0 ≈ 3 × 10 −5 at 30 ppbv O 3 STP) and between 4.8 × 10 −5 and 2.2 × 10 −6 for the steady-state uptake coefficient (γ ss ≈ 7 × 10 −6 at 30 ppbv O 3 STP). At very high O 3 concentrations the surface was deactivated, and O 3 uptake ceased after a certain exposure period. Sample re-activation (i.e. de-passivation) was found to occur over periods of hours, after exposure to O 3 had ceased, suggesting that re-activation processes play a role both in the laboratory and in the atmosphere.

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Section: The Uptake Mechanismmentioning

confidence: 99%

Section: The Uptake Mechanismmentioning

confidence: 99%

Section: The Uptake Mechanismmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ozone decomposition on Saharan dust: an experimental investigation

2003

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“…Grupos hidroxila estão presentes em todas as superfíci-es de óxidos metálicos, entretanto, a quantidade e propriedade destes grupos dependem da natureza do óxido 50 . Bulanin e colaboradores 51 concluíram que a adsorção de ozônio sobre a superfí-cie de óxidos do tipo n resulta na produção de oxigênio e/ou oxidação da superfície. Já a interação do ozônio com óxidos do tipo p leva à decomposição do ozônio via formação de espécies radicalares (principalmente o ânion radical superóxido).…”

Section: Ozônio Catalítico Heterogêneounclassified

Métodos emergentes para aumentar a eficiência do ozônio no tratamento de águas contaminadas

Mahmoud¹,

Freire²

2007

Quím. Nova

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Recebido em 30/9/05; aceito em 6/2/06; publicado na web em 30/8/06 NEW METHODS FOR ENHANCING OZONE EFFICIENCY ON CONTAMINATED WATER TREATMENT. Many industrial processes produce effluents with a wide variety of xenobiotic organic pollutants, which cannot be efficiently degraded by conventional biological treatments. Thus, the development of new technologies to eliminate these refractory compounds in water has become very imperative in order to assure the quality of this important resource. Ozonation is a very promising process for the treatment of wastewaters containing non-easily removable organic compounds. The present work aims at highlighting new methods of enhancing the efficiency of ozone towards the removal organic pollutants in aqueous solution. Special attention is given to catalytic ozonation processes contemplating homo-and heterogeneous catalysis, their activity and mechanisms. Recent results and future prospects about the application of these processes to real effluents are also evaluated.Keywords: catalytic ozonation; environmental chemistry; advanced oxidation processes. INTRODUÇÃODesde as últimas décadas do século passado, a sociedade tem adquirido uma conscientização crescente a respeito dos problemas ambientais e seus efeitos para a qualidade de vida desta e das futuras gerações. Apesar disso, a integridade de vários ecossistemas vem sendo afetada, de maneira preocupante, por uma série de atividades antropogênicas, levando a um risco de degradação irreversível do meio ambiente.Neste panorama, as preocupações com o uso e a qualidade da água adquirem especial importância devido à relevância deste recurso e ao aumento desenfreado de sua demanda, resultante principalmente do crescimento acelerado da população e estilo de vida da sociedade contemporânea (que dentre outras coisas, prima por padrões de conforto e bem-estar em detrimento do equilíbrio dos recursos naturais). De fato, é difícil imaginar qualquer tipo de organização dos seres humanos em sociedade que dispense o uso da água, uma vez que esta substância é essencial não somente para a manutenção das atividades biológicas básicas (a água compõe parte significativa das células de todos os seres vivos, estando envolvida em processos de transporte de nutrientes e dejetos; manutenção de temperatura; produção e armazenamento de energia, etc.), mas também para o desenvolvimento das atividades produtivas (agrícolas ou industriais).Talvez por ser relativamente abundante, a água tornou-se tão banal que sua presença, embora indispensável, não desperta a merecida atenção e valorização. Apesar da água ser um recurso natural renovável (qualquer que seja seu uso, no final ela é restituída ao ambiente/origem), durante muito tempo teve-se uma concepção errônea de inesgotabilidade desta substância. Embora seja verdade que o homem não faça a água simplesmente desaparecer da natureza (como tem feito com florestas e algumas reservas minerais), a qualidade de uma infinidade de recursos hídricos tem sido seriamente comprometida 1,2 .Dentre as várias atividades ant...

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Reactions of Peroxides on Solid Surfaces

Mello

González‐Núñez

2014

Patai's Chemistry of Functional Groups

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This article describes the different roles that solid surfaces play in heterogeneous reactions involving peroxides, namely, (i) the solid surface interacts with the peroxide in the absence of any other substrate, (ii) the solid surface promotes the reaction activating either the peroxide or the substrate, (iii) the peroxide forms part of the solid active surface, and (iv) the substrate forms part of the active surface. The chapter covers reactions involving peroxides or discrete peroxydic transient species on solid surfaces or at solid–liquid and solid–gas interfaces, and provides general descriptions of different solid materials, details on reaction conditions, and synthetic procedures for solid‐supported reagents.

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Infrared Study of Ozone Adsorption on TiO2 (Anatase)

Cited by 101 publications

References 1 publication

Ozone decomposition on Saharan dust: an experimental investigation

Ozone decomposition on Saharan dust: an experimental investigation

Métodos emergentes para aumentar a eficiência do ozônio no tratamento de águas contaminadas

Reactions of Peroxides on Solid Surfaces

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