Catalytic oxidation of benzene with ozone over alumina-supported manganese oxides

Einaga, Hisahiro; Futamura, Shigeru

doi:10.1016/j.jcat.2004.07.029

Cited by 230 publications

(131 citation statements)

References 26 publications

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“…On the other hand, the highest reaction rate value was registered for the 2NH4Z1 823 K sample, with the highest density of strong Lewis acid sites (282.8 µmol·g −1 ). These strong sites enhance gaseous ozone decomposition, generating active atomic oxygen (O • ), as previously reported [26,29,40,41]. Hence, the generation of a high number of active atomic oxygen species [33][34][35][36][37] could be responsible for the catalytic ozonation of toluene in a new kind of advanced oxidation process.…”

Section: Catalytic Ozonation Using Natural and Modified Zeolites At 2mentioning

confidence: 60%

Catalytic Ozonation of Toluene Using Chilean Natural Zeolite: The Key Role of Brønsted and Lewis Acid Sites

et al. 2018

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Abstract:The influence of surface physical-chemical characteristics of Chilean natural zeolite on the catalytic ozonation of toluene is presented in this article. Surface characteristics of natural zeolite were modified by acid treatment with hydrochloric acid and ion-exchange with ammonium sulphate. Prior to catalytic ozonation assays, natural and chemically modified zeolite samples were thermally treated at 623 and 823 K in order to enhance Brønsted and Lewis acid sites formation, respectively. Natural and modified zeolite samples were characterised by N 2 adsorption at 77 K, elemental analysis, X-ray fluorescence, and Fourier transform infrared (FTIR) spectroscopy, using pyridine as a probe molecule. The highest values of the reaction rate of toluene oxidation were observed when NH4Z1 and 2NH4Z1 zeolite samples were used. Those samples registered the highest density values of Lewis acid sites compared to other samples used here. Results indicate that the presence of strong Lewis acid sites at the 2NH4Z1 zeolite surface causes an increase in the reaction rate of toluene oxidation, confirming the role of Lewis acid sites during the catalytic ozonation of toluene at room temperature. Lewis acid sites decompose gaseous ozone into atomic oxygen, which reacts with the adsorbed toluene at Brønsted acid sites. On the other hand, no significant contribution of Brønsted acid sites on the reaction rate was registered when NH4Z1 and 2NH4Z1 zeolite samples were used.

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Section: Catalytic Ozonation Using Natural and Modified Zeolites At 2mentioning

confidence: 60%

Catalytic Ozonation of Toluene Using Chilean Natural Zeolite: The Key Role of Brønsted and Lewis Acid Sites

et al. 2018

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“…To avoid deactivation of photocatalysts and increase the efficiency of mineralization of contaminants, addition of ozone has been the focus of much recent research (Kim et al, 2003;Kasprzyk-Hordern et al, 2003;Pengyi et al, 2003;Einaga and Futamura, 2004;Zhang and Liu, 2004;Giri et al, 2007). In photocatalyst ozonization, the photocatalytic oxidation rate greatly increases due to synergistic photocatalytic and photochemical effects in the combined systems (Jeong et al, 2004;Jeong et al, 2005;Jeong et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Removal of Ethylene and Secondary Organic Aerosols Using UV-C254 + 185 nm with TiO2 Catalyst

Chang

Sekiguchi

Wang

et al. 2013

Aerosol Air Qual. Res.

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In this investigation we evaluated the feasibility and effectiveness of ozone-producing UV (254 + 185 nm) irradiation and a TiO 2 photocatalyst for degradation of ethylene, which is strongly hydrophobic and does not decompose easily in a humid environment. Tests were performed in a photoreactor (V = 0.55 L) under UV irradiation at various wavelengths (365, 254 and 254 + 185 nm), relative humidities (RH < 1% and RH > 86%), atmospheres (pure N 2 and air), residence times (11-33 sec), initial ethylene concentrations in the range of 25-105 ppmv and TiO 2 contact areas (86.4-259 cm 2 ) with presumably ambient pressure and temperature.The experimental results demonstrated that the use of TiO 2 under 254 + 185 nm UV irradiation significantly enhanced the photodegradation of ethylene compared to the case of UV irradiation alone, due to the synergistic effect of photochemical oxidation in the gas phase and photocatalytic oxidation on the TiO 2 surface. Photodegradation induced with 254 + 185 nm UV irradiation was compared with photodegradation induced with UV irradiation at wavelengths of 365 and 254 nm. The highest conversion and mineralization levels were obtained with 254 + 185 nm UV irradiation among the three tested UV sources. Moreover, irradiating with 254 +185 nm light generated secondary organic aerosols (SOA) via gas-to-particle conversion of organic compounds in the air stream. The results indicate that the concentration of generated SOAs decreased in the presence of the TiO 2 catalyst, and thus that TiO 2 may be used to effectively control the emissions of undesirable SOAs.In an application test, for photocatalytic oxidation with 254 + 185 nm UV irradiation, corresponding to a flow rate of 0.5 L/min, and an initial concentration of 34 ppmv, over 90% of the inlet ethylene could be degraded.

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“…Some studies have shown that the increased humidity is beneficial to improve the removal efficiency of ozone decomposition and air pollutants. Specific processes are shown in Equations (29-34) (Dhandapani and Oyama, 1997;Einaga and Futamura, 2004b):…”

Section: Vuv Photolysis-ozone Catalytic Oxidation (Vuv-ozco)mentioning

confidence: 99%

Recent Development of VUV-Based Processes for Air Pollutant Degradation

Huang

et al. 2016

Front. Environ. Sci.

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As air pollution poses a great challenge around the globe, it is essential to fashion out a way of efficiently degrading the air pollutants. Vacuum Ultraviolet (VUV)-based processes are an emerging and promising technology for environmental remediation such as air cleaning, wastewater treatment, and air/water disinfection. When VUV irradiation, photolysis, photocatalysis, and ozone-assisted oxidation are involved at the same time, it results in the fast degradation of air pollutants because of their strong oxidizing capacity. The mechanisms of how the oxidants are produced and how they react are discussed in this review. This paper focuses mainly on the three VUV-based oxidation processes including VUV photolysis, VUV combined with ozone-assisted oxidation, and VUV-PCO with emphasis on their mechanisms and applications. Also, the outlook of these processes are proposed in this paper.

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Catalytic oxidation of benzene with ozone over alumina-supported manganese oxides

Cited by 230 publications

References 26 publications

Catalytic Ozonation of Toluene Using Chilean Natural Zeolite: The Key Role of Brønsted and Lewis Acid Sites

Catalytic Ozonation of Toluene Using Chilean Natural Zeolite: The Key Role of Brønsted and Lewis Acid Sites

Removal of Ethylene and Secondary Organic Aerosols Using UV-C254 + 185 nm with TiO2 Catalyst

Recent Development of VUV-Based Processes for Air Pollutant Degradation

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