Hydrodechlorination of Chlorinated Ethanes by Nanoscale Pd/Fe Bimetallic Particles
Publication: Journal of Environmental Engineering
Volume 131, Issue 1
Abstract
Chlorinated ethanes are contaminants commonly found in soil and groundwater. The potential of nanoscale bimetallic particles for the hydrodechlorination of seven chlorinated ethanes was evaluated in batch experiments. Hexachloroethane (HCA) , pentachloroethane (PCA) , 1,1,2,2-tetrachloroethane (1,1,2,2- , ), and 1,1,1,2-tetrachlorethane (1,1,1,2- , ) were rapidly hydrodechlorinated (9–28 min half-lives) at a nanoparticle loading of 5 g/L. End products were ethane (61–87%) and ethylene (6–16%). Only one chlorinated intermediate, a corresponding -elimination product, appeared temporarily during the reactions. Reductive dechlorination of 1,1,1-trichloroethane (1,1,1-TCA, ) to ethane was completed at a relatively slower rate with half-life at 44.9 min. Little reduction of dichloroethane was observed within 24 h. The Pd/Fe bimetallic nanoparticles generally exhibit much higher reactivity when compared with conventional micro- and millimeter scale iron powders. The hydrodechlorination reactions are more complete, with a much higher yield of ethane and lower yield of chlorinated byproducts. A kinetic model incorporating a transition state species was proposed. Results from this work suggest that the Pd/Fe bimetallic nanoparticles may represent a treatment alternative for in situ remediation of chlorinated ethanes.
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Acknowledgments
This work is supported partially by U.S. Environmental Protection Agency (USEPA) Grant No. 829625 and by a CAREER award to W.Z. from U.S. National Science Foundation (NSF) Grant No. 9983855.
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Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 131 • Issue 1 • January 2005
Pages: 4 - 10
Copyright
© 2004 ASCE.
History
Received: Sep 19, 2002
Accepted: Mar 5, 2004
Published online: Jan 1, 2005
Published in print: Jan 2005
Notes
Note. Associate Editor: Mark J. Rood
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