Bimetallic catalyst system for the degradation of PCBs in sediments.

In this paper, we report the successful application of a patent-pending reduced bimetallic nanoparticle catalytic system developed for the remediation of polychlorinated biphenyl (PCB)-contaminated sediment and aquatic media. The formation of bimetallic nanoparticles associated with the granular activated carbon (GAC) were confirmed by high-resolution transmission electron microscopy. X-ray photoelectron spectroscopy showed the presence of the bimetallic matrix in reduced, albeit mixed, states. In the degradation studies, the bimetallic nanoparticles were deposited on a GAC substrate and utilized to treat both a surrogate PCB, 2-Chlorobiphenyl (2-CBP) in water and contaminated bottom-river sediments collected from a site with mixed-congener PCB contamination. The degradation studies on non-degassed water contaminated with 2-CBP at room temperature showed a high yield of 2-CBP degradation to biphenyl and phenol. Results from the bottom-river sediments contaminated with PCBs (tested in laboratory environment at ambient temperature and atmospheric conditions, not degassed) have indicated the bimetallic catalyst has great promise for remedial application in sediment and aquatic media. Results illustrate that this newly-developed and patent-pending catalytic system degrades PCBs through stepwise dichlorination, with expected byproducts such as biphenyl and phenol leading to mineralization of the PCBs.