Photoassisted dehalogenation of organo-chlorine compounds by paratungstate A in aqueous solutions Original Research Article

Nearly neutral aqueous solutions of 22 organo-chlorine compounds undergo photodegradation (λ > 250 nm) catalyzed by paratungstate A anion, [W7O24]6−, which was obtained by adjusting pH levels of the Na2WO4 solution to 6–7. In each case the organic substrate was decomposed through dehalogenation. The rate of Cl− formation strongly depends on substrates. The photochemical redox reaction between paratungstate A and substrates proceeds via precomplexation. The Langmuir-type dependence of the reaction rates on the concentration of substrates provides a promising method for the dechlorination of alkyl- and aromatic-chloride compounds such as ClCH2CH2CH2Cl, C3H7Cl, and C6H5CH2Cl.