Effect of co-contaminants on the dechlorination of polychlorinated biphenyls

A promising photolysis based technology to dechlorinate polychlorinated biphenyls (PCBs), extracted from soils, in alkaline isopropanol (IPA) as reaction medium has been proposed. To be marketable the impact of co-contaminants extracted along with the PCBs, on the photodechiorination process needs investigation. In this paper the effectiveness of the photodeclorination process on PCBs extracted from samples of a representative soil containing co-contaminants is reported. The pholodechl ori nation or PCBs extracted from weathered soils showed promising results of more than 76% dechlorination within the first hour of UV irradiation. Nearly complete dechlorination (96%) was achieved after 2 h of UV irradiation. To provide quantitative controlled appraisal of the effect of co-contaminants and explanation of the effects, dechlorination of neat Aroclor 1254 in the presence of the common co-contaminant, transformer oil, was evaluated. Further, the effect of transformer oil on some of the individual PCB congeners in the Aroclor mixture was also studied. The difference in the maximum percentage dechlorination of PCBs with and without transformer oil is 15%. Key words: PCBs, extraction, dechlorination, 2-propanol, transformer oil, co-contaminants. Une technologie prometteuse basee sur la photolyse est proposee pour dechlorer les BPC extraits des sols dans un milieu de reaction compose d'alcool isopropylique alcalin. Afin d'etre commercialisable, il faut examiner l'impact des co-contaminants extraits avec les BPC lors du processus de photo-dechloration. Dans eel article, l'efficacite du processus de photo-dechloralion sur les BPC extraits d'echantillons d'un sol representatif contenant des co-contaminants est presentee. La photo-chloration des BPC extrails de sols alleres a monlre des resultals de dechloraiion prometteurs de plus de 76% dans la premiere heure de rayonnement UV. Une dechloration presque complete (96 %) a ete realisee apres 2 heures de rayonnement UV. Pour fournir une evaluation quantitative controlee de l'effet des co-contaminants et I'explication des effets. la dechloration d'Aroclor 1254 pur en presence du co-contaminant commun, de l'huile de transformateur, a ete evaluee. De plus, l'effet de l'huile de transformateur sur certains des congeneres individuels des BPC dans le melange d'Aroclor a egalement ete etudie. La difference dans le pourcentage maximum de dechloration des BPC avec et sans huile de transformateur est de 15%. Mots-cles: BPC. extraction, dechloration. alcool isopropylique. huile de transformateur, co-contaminants. [Traduit par la Redaction]
Introduction Recent successes on the dechlorination of polychlorinated biphenyls (PCBs) using UV, has opened possibilities of applying this technique to remediate PCB contaminated soils and sediments. The dechlorination of PCBs [...]