.gamma.-Ray Destruction of Individual PCB Congeners in Neutral 2-propanol

Arbon, R.E.; Mincher, Bruce J.; Knighton, W. B.

doi:10.1021/es00061a030

Cited by 40 publications

(22 citation statements)

References 13 publications

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“…It has been generally observed using metallic nanoparticles that the resistivity of the substituted chlorine to dechlorination follows the order ortho [ meta > para. 95,96 This dechlorination profile of PCB 77 was also observed in the present studies irrespective of whether Pd/Fe nanotubes or nanoparticles were used. This similar dechlorination selectivity indicates that the curvature of the nanotubes has no effect, within the error, on the selectivity of the dechlorination reaction.…”

Section: Dechlorination Of Pcb 77supporting

confidence: 85%

Development of reactive Pd/Fe bimetallic nanotubes for dechlorination reactions

2011

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We described the synthesis and characterization of a new class of bimetallic nanotubes based on Pd/Fe and demonstrated their efficacy in the dechlorination of PCB 77, a polychlorinated biphenyl. Onedimensional iron metal nanotubes of different diameters were prepared by electroless deposition within the pores of PVP-coated polycarbonate membranes using a simple technique under ambient conditions. The longitudinal nucleation of the nanotubes along the pore walls was achieved by mounting the PC membrane between two halves of a U-shape reaction tube. The composition, morphology, and structure of the Pd/Fe nanotubes were characterized by transmission electron microscopy, scanning electron microscopy, inductively coupled plasma-atomic emission spectroscopy, and X-ray powder diffraction spectroscopy. The as-prepared Pd/Fe bimetallic nanotubes were used in dechlorination of 3,3′,4,4′-tetrachlorobiphenyl (PCB 77). In comparison with Pd/Fe nanoparticles, the Pd/Fe nanotubes demonstrated higher efficiency and faster dechlorination of the PCB.

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Section: Dechlorination Of Pcb 77supporting

confidence: 85%

Development of reactive Pd/Fe bimetallic nanotubes for dechlorination reactions

2011

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“…207 in Table 1. The resistance of the lower homologues toward reductive dechlorination may be related to the increase in the lowest unoccupied molecular orbital (LUMO) energy which decreases the probability of the reductive electron to occupy the LUMO, thus decreasing the probability of the formation of the reactive excimer of the PCB molecule (21). Figure 2B also shows that many lower congeners below the penta-substituted congener are formed after the reaction.…”

Section: Resultsmentioning

confidence: 99%

Reductive Dechlorination of Polychlorinated Biphenyls by Zerovalent Iron in Subcritical Water

Yak

Wenclawiak

Cheng

et al. 1999

Environ. Sci. Technol.

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A method for remediation of PCB-contaminated soil and sediments is described that uses zerovalent iron as the dechlorination agent and subcritical water extraction (SWE) as the transporting medium. By using 100-mesh iron powder and SWE conditions of 250 °C and 10 MPa on Aroclor 1260 for 1-8 h, the higher chlorine-substituted homologues were completely reduced to their lowersubstituted counterparts. The lower-substituted congeners were subsequently near-completely dechlorinated. The initial findings indicate that this technique may be a viable method for remediation of PCB-contaminated soil and sediments.

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“…The reaction efficiency has been observed to vary significantly in different solvents (12,13,17,18,24), and a chain dechlorination reaction has been reported to occur in alkaline solutions of 2-propanol (13). In addition, the yield for radiation-induced dechlorination of different PCB congeners has, in general, been demonstrated to increase with an increasing degree of chlorine substitution (12,21), consistent with the corresponding decrease in the energy level of the lowest unoccupied molecular orbital (21).…”

Section: Introductionmentioning

confidence: 70%

“…The radiation-induced decomposition of PCBs has been investigated in a variety of organic solvents (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27), including mineral oils (22)(23)(24)(25)27), and in a 2-propanol soil slurry (14). Detailed scavenger studies by Mincher et al (25) and Arbon et al (22) implicated the solvated electron as the major reactive species in the γ-radiation-induced destruction of PCBs in neutral solutions of both 2-propanol (25) and isooctane (22).…”

Section: Introductionmentioning

confidence: 99%

Degradation of Polychlorinated Biphenyls Induced by Ionizing Radiation in Aqueous Micellar Solutions

Schmelling

Poster

Chaychian

et al. 1998

Environ. Sci. Technol.

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This investigation examines the γ-radiation-induced degradation of polychlorinated biphenyls (PCBs) in aqueous surfactant solutions. Dichloro-, tetrachloro-, and decachlorobiphenyl congeners were solubilized in water using a commercially available non-ionic surfactant, Triton X-100, and subsequently irradiated by a 60 Co γ-source. Rates and extent of dechlorination were determined at different surfactant concentrations, and intermediate species and byproducts were quantified. Pulse radiolysis was used to measure rates of reaction between PCBs and the solvated electron as well as rates of electron scavenging by the surfactant. Experiments were also conducted in organic solvents, and these results have been compared to those observed in the aqueous surfactant solutions. Each PCB congener was fully dechlorinated by ionizing radiation in the micellar systems. Initial chloride yields were directly proportional to the level of chlorination of the PCB congeners. Scavenging of the aqueous electron by the surfactant was significant, and PCB degradation efficiency improved markedly at lower surfactant concentrations. PCB transformation occurred primarily through reductive dechlorination, forming lower chlorinated PCBs and biphenyl. Rates of PCB degradation were substantially higher in aqueous surfactant solutions than in diethyl ether and petroleum ether. This suggests that solubilizing PCBs in water using a surfactant prior to irradiation may provide a considerable improvement in contaminant degradation efficiency in comparison to using an organic solvent or irradiating PCBs directly in oil.

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.gamma.-Ray Destruction of Individual PCB Congeners in Neutral 2-propanol

Cited by 40 publications

References 13 publications

Development of reactive Pd/Fe bimetallic nanotubes for dechlorination reactions

Development of reactive Pd/Fe bimetallic nanotubes for dechlorination reactions

Reductive Dechlorination of Polychlorinated Biphenyls by Zerovalent Iron in Subcritical Water

Degradation of Polychlorinated Biphenyls Induced by Ionizing Radiation in Aqueous Micellar Solutions

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