Photocatalytic mineralization of chlorinated organic pollutants in water by polyoxometallates. Determination of intermediates and final degradation products.

Citation
A. Hiskia et al., Photocatalytic mineralization of chlorinated organic pollutants in water by polyoxometallates. Determination of intermediates and final degradation products., RES CHEM IN, 26(3), 2000, pp. 235-251
Citations number
32
Categorie Soggetti
Chemistry
Journal title
RESEARCH ON CHEMICAL INTERMEDIATES
ISSN journal
09226168 → ACNP
Volume
26
Issue
3
Year of publication
2000
Pages
235 - 251
Database
ISI
SICI code
0922-6168(2000)26:3<235:PMOCOP>2.0.ZU;2-Z
Abstract
Homogeneous aqueous solutions of organochlorine pesticides and chlorophenol s, namely, Lindane, hexachlorobenzene and 2,4-dichlorophenol (2,4DCP), unde rgo effective photodegradation upon photolysis with UV and near visible lig ht in the presence of a characteristic polyoxometallate catalyst PW12O403-. These substrates remained, practically, intact (lindane, HCB) or underwent minor degradation under similar conditions in absence of catalyst. The mai n oxidant appears to be OH radicals formed by the reaction of the excited p olyoxometallate with H2O. The system compares with the widely published TiO 2. Chlorohydroquinone (CIHQ), hydroquinone (HQ), chlorobenzoquinone (CIBQ), benzoquinone (BQ), 3,5-dichlorocatechol (3,5DCC) and 4-chlorocatechol (4CC ), among others, were identified as the main aromatic intermediates in the photodegradation of 2,4DCP. Acetic acid was detected as ring cleavage produ ct. In all cases the final photodegradation leads to complete mineralizatio n of substrates to CO2 and HCl.