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Dechlorination of DDT mediated by bimetallic systems

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Title Dechlorination of DDT mediated by bimetallic systems
 
Creator GAUTAM, SK
SUMATHI, S
 
Subject metals
catalysis
cobalt
ddt
dechlorination
magnesium
nickel
zero-valent metal
zinc
 
Description DDT clechlorination efficiencies of bimetallic systems, namely, Mg degrees-Zn, Mg degrees-Ni, and Mg degrees-Co were compared. All the systems transformed DDT with efficiencies exceeding 98% within 24 h. Based on GC-ECD and GC-MS analyses a step-wise and sequential clechlorination of DDT by Mg degrees-Zn system in 1:1 water acetone phase via 1,1 dichloro, 2,2- bis (p-chlorophenyl) ethane (DDD), 1, chloro, 2,2 bis (p-chlorophenyl) ethane (DDMS) to 2,2 bis (p-chlorophenyl) ethane (DDNS) was noted. Accumulation of DDNS as the end product indicates that all three alkyl chlorine atoms of DDT were removed by Mg degrees-Zn system. Mg degrees-Co also showed almost complete removal of DDT in water-acetone phase that was accompanied by the accumulation of DDD followed by a decline in its concentration as a function of time. On the other hand, Mg degrees-Ni system exhibited inefficient removal of DDT in water-acetone phase. In pure acetone phase, Mg degrees-Co system and Mg degrees-Ni dechlorinated DDT with the accumulation of DDE and DDMU as end products following 24 h of reaction. The presence of surfactants or organic solvents is required to ensure solubilization of DDT. Also addition of acid is essential to provide sufficient protons for efficient reductive clechlorination via hydrogenation. Advantage of Mg* based dehalogenation reactions is that they occur at high rates under ambient temperatures, and pressure and oxygen need not be excluded in the reaction phase. Our studies revealed that Mg degrees-Zn is the best option among all tested systems due to its high reactivity and low cost, and may be used to treat DDT contaminated water.
 
Publisher SELPER LTD, PUBLICATIONS DIV
 
Date 2011-08-29T03:42:23Z
2011-12-26T12:58:22Z
2011-12-27T05:48:07Z
2011-08-29T03:42:23Z
2011-12-26T12:58:22Z
2011-12-27T05:48:07Z
2006
 
Type Article
 
Identifier ENVIRONMENTAL TECHNOLOGY, 27(4), 387-394
0959-3330
http://dx.doi.org/10.1080/09593332708618659
http://dspace.library.iitb.ac.in/xmlui/handle/10054/11944
http://hdl.handle.net/10054/11944
 
Language en