Photocatalytic oxidation of acetonitrile in aqueous suspension of titanium dioxide irradiated by sunlight

Augugliaro, Vincenzo; Prevot, Alessandra Bianco; Vázquez, Julián; García‐López, Elisa I.; Irico, A.; Loddo, Vittorio; Malato, Sixto; Marcı̀, Giuseppe; Palmisano, Leonardo; Pramauro, Edmondo

doi:10.1016/s1093-0191(02)00106-5

Cited by 29 publications

(11 citation statements)

References 14 publications

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“…In the liquid phase, acetonitrile degradation was quite slow. OH radical attack occurs on (CH 3 ) radical, giving formic acid and HOCN, as observed by Augugliaro et al [44]. Also, OCN ) is slowly photo-oxidised, through the mechanism reported in the sequence 2.…”

Section: Nitrogen With Triple Bondsmentioning

confidence: 68%

The fate of organic nitrogen in photocatalysis: an overview

2005

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Photocatalytic processes taking place on TiO 2 have been widely employed and investigated. However, nitrogen-containing substances have not received the same attention as other substrates. Mineralization of such compounds is expected to lead to the formation of N 2 gas, ammonium and/or nitrate ions through photooxidative and/or photoreductive pathways. Herein, we will focus the attention on how the chemical structure may influence both the ratio and the extent of formation of the inorganic nitrogen. This review will consider heteroaromatic compounds, containing two or three-nitrogen in the ring, and small molecules, that could be formed as intermediate during the degradation of more complex substrates (i.e. pesticides), such as amino-alcohols, and molecules containing amide groups and nitriles. The fate final of the nitrogen in all these structures has been rationalized on the basis of the nature of NAN and CAN bonds in which the organic nitrogen is involved.

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Section: Nitrogen With Triple Bondsmentioning

confidence: 68%

The fate of organic nitrogen in photocatalysis: an overview

2005

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“…The CN -moiety renders it a particularly interesting molecule to examine, as it is representative of a number of toxic materials which are candidates for TiO 2 -based oxidation processes. However, to date, only a limited number of studies have appeared on the catalytic degradation of acetonitrile over TiO 2 either under dark conditions [6,7] or under UV irradiation [8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

An EPR investigation of acetonitrile reactivity with superoxide radicals on polycrystalline TiO2

2009

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The interaction of acetonitrile with superoxide radicals over a polycrystalline TiO 2 (Degussa P25) surface was investigated using continuous-wave electron paramagnetic resonance (cw-EPR) spectroscopy. For the first time, a thermally unstable radical intermediate has been observed following the low-temperature exposure of acetonitrile to surface-adsorbed O 2 -radicals. The radical intermediate has been identified as an [O 2 -ÁÁÁCH 3 CN] type surface complex characterised by the g values of g 1 = 2.031, g 2 = 2.010 and g 3 = 2.003. This surface complex is thermally unstable and decomposes at temperatures of T [ 240 K. A second oxygen-centred species was also observed following acetonitrile adsorption, characterised by the spin Hamiltonian parameters of g 1 = 2.028, g 2 = 2.010, g 3 = 2.004, A 1 = 1.2 mT, A 2 = 1.0 mT and A 3 = 1.0 mT, and was assigned to a hydroperoxy radical (HO 2 • ).

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“…Isocyanate was also found adsorbed onto the catalyst surface; its presence is considered a clue of the formation of free cyanide. The photocatalytic oxidation of acetonitrile was also carried out in aqueous suspensions irradiated by sunlight [20]. Acetonitrile was oxidised to carbonate and nitrate and the main inorganic intermediate detected was cyanate, while only traces of cyanide and nitrite were found.…”

Section: Introductionmentioning

confidence: 99%

The role of water in the photocatalytic degradation of acetonitrile and toluene in gas‐solid and liquid‐solid regimes

Addamo

Augugliaro

Coluccia

et al. 2006

International Journal of Photoenergy

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Photocatalytic degradation of acetonitrile and toluene was carried out both in gas-solid and in liquid-solid regimes by using commercialTiO2samples (Merck and Degussa P25). The investigation was mainly aimed to study the influence of water present in the reaction environment on the mechanism and degradation rate of two probe molecules. In gas-solid regime, the reacting mixture consisted of toluene or acetonitrile, oxygen, nitrogen, and water vapour. The main degradation product of toluene wasCO2with small amounts of benzaldehyde. In the presence of water vapour, the activity ofTiO2Merck remained stable but greatly decreased if water was absent.TiO2Degussa P25 continuously deactivated, even in the presence of water vapour. With both catalysts, the photodegradation products of acetonitrile wereCO2and HCN; the activity was stable and was independent of the presence of water vapour in the reacting mixture. The production of HCN represents a drawback of acetonitrile photocatalytic degradation but the elimination of HCN is not actually a problem. In liquid-solid regime, the main intermediates of toluene photodegradation werep-cresol and benzaldehyde; traces of pyrogallol and benzyl alcohol were also found. Benzoic acid, hydroquinone, and trans, trans muconic acid were detected only whenTiO2Merck was used. The photodegradation products of acetonitrile were cyanide, cyanate, formate, nitrate, and carbonate ions.

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Photocatalytic oxidation of acetonitrile in aqueous suspension of titanium dioxide irradiated by sunlight

Cited by 29 publications

References 14 publications

The fate of organic nitrogen in photocatalysis: an overview

The fate of organic nitrogen in photocatalysis: an overview

An EPR investigation of acetonitrile reactivity with superoxide radicals on polycrystalline TiO2

The role of water in the photocatalytic degradation of acetonitrile and toluene in gas‐solid and liquid‐solid regimes

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