In:
Environmental Toxicology and Chemistry, Wiley, Vol. 18, No. 6 ( 1999-06), p. 1091-1096
Abstract:
Iron granules ( 〈 10 μ) (Fe°‐H 2 O) and palladium‐treated iron granules (Pd/Fe°‐H 2 O) in contact with water have been tested as a potential means to dechlorinate chloromethanes (CCl 4 , CHCl 3 , and CH 2 Cl 2 ) that are commonly generated in teaching chemistry laboratories. Palladium treatment enhanced the rate of dechlorination of CCl 4 by a factor of about seven compared to the untreated Fe°‐H 2 O, but the potential toxic effect of palladium remains a concern. Oxygen in the aqueous solution reduced the dechlorination rates of CCl 4 with both Fe°‐H 2 O and Pd/Fe°‐H 2 O by at least a factor of three. Nevertheless, from the consideration of remediating solvent wastes, both systems appear suitable for treating CCl 4 and possibly CHCl 3 wastes, even in the presence of oxygen. The reactivities of the three chloromethanes toward the Fe°‐H 2 O were vastly different. The dechlorination rate of CCl 4 was by far the highest, followed by that of CHCl 3 , and CH 2 Cl 2 was virtually unreactive toward the Fe°‐H 2 O system. Dechlorination reactions of CCl 4 and CHCl 3 were systematically examined on both Fe°‐H 2 O and Pd/Fe°‐H 2 O. On the basis of the data, it appears that CCl 4 is successively dechlorinated to form CH 4 via the formation of partially dechlorinated intermediates. Proton transfer to various intermediates produces the chloromethanes: CHCl 3 , CH 2 Cl 2 , and CH 3 Cl. Furthermore, CH 4 formation, independent of the proton‐transferring reactions, appears to be selectively stimulated by palladium (Pd/Fe°‐H 2 O).
Type of Medium:
Online Resource
ISSN:
0730-7268
,
1552-8618
DOI:
10.1002/etc.5620180604
Language:
English
Publisher:
Wiley
Publication Date:
1999
detail.hit.zdb_id:
2027441-5
SSG:
12
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