The role of water in the photocatalytic degradation of acetonitrile and toluene in gas-solid and liquid-solid regimes
Photocatalytic degradation of acetonitrile and toluene was carried out both in gas-solid and in liquid-solid regimes by using commercial TiO2 samples (Merck and Degussa P25). The investigation was mainly aimed to study the influence of water present in the reaction environment on the mechanism and d...
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| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2006-01-01
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| Series: | International Journal of Photoenergy |
| Online Access: | http://dx.doi.org/10.1155/IJP/2006/39182 |
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| Summary: | Photocatalytic degradation of acetonitrile and toluene was carried
out both in gas-solid and in liquid-solid regimes by using
commercial TiO2 samples (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 was CO2 with small amounts of benzaldehyde. In
the presence of water vapour, the activity of TiO2 Merck remained stable but greatly decreased if water was absent. TiO2 Degussa P25 continuously deactivated, even in the
presence of water vapour. With both catalysts, the
photodegradation products of acetonitrile were CO2 and 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 were p-cresol and benzaldehyde; traces of
pyrogallol and benzyl alcohol were also found. Benzoic acid,
hydroquinone, and trans, trans muconic acid were detected only
when TiO2 Merck was used. The photodegradation products of
acetonitrile were cyanide, cyanate, formate, nitrate, and carbonate
ions. |
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| ISSN: | 1110-662X 1687-529X |