New Paper: Fate/Remediation of 1,2,3-Trichloropropane (TCP)

[PGT]

Our first major papers on the fate and remediation of the emerging
contaminant 1,2,3-Trichloropropane (TCP).

This paper also presents our first results using zero-valent zinc as a
reductant for degradation of contaminants. To put the results with Zn
(0) and TCP into perspective (vis-a-vis other zero-valent metals and
other chlorinated solvents), we have further developed the kSA vs. kM
plot format.

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CITATION: Sarathy, V., P. G. Tratnyek, J. T. Nurmi, R. L. Johnson, and
G. O. B. Johnson. 2009/2010. Degradation of 1,2,3-trichloropropane
(TCP): Hydrolysis, elimination, and reduction by iron and zinc.
Environ. Sci. Technol. Published online December 14, 2009 (ASAP).

ABSTRACT: 1,2,3-Trichloropropane (TCP) is an emerging contaminant
because of increased recognition of its occurrence in groundwater,
potential carcinogenicity, and resistance to natural attenuation. The
physical and chemical properties of TCP make it difficult to
remediate, with all conventional options being relatively slow or
inefficient. Treatments that result in alkaline conditions (e.g.,
permeable reactive barriers containing zerovalent iron) favor base-
catalyzed hydrolysis of TCP, but high temperature (e.g., conditions of
in situ thermal remediation) is necessary for this reaction to be
significant. Common reductants (sulfide, ferrous iron adsorbed to iron
oxides, and most forms of construction-grade or nano-Fe0) produce
insignificant rates of reductive dechlorination of TCP. Quantifiable
rates of TCP reduction were obtained with several types of activated
nano-Fe0, but the surface area normalized rate contants (kSA) for
these reactions were lower than is generally considered useful for in
situ remediation applications (10-4 L m-2 h-1). Much faster rates of
degradation of TCP were obtained with granular Zn0, (kSA = 10-3 - 10-2
L m-2 h-1) and potentially problematic dechlorination intermediates
(1,2- or 1,3-dichloropropane, 3-chloro-1-propene) were not detected.
The advantages of Zn0 over Fe0 are somewhat peculiar to TCP and may
suggest a practical application for Zn0 even though it has not found
favor for remediation of contamination with other chlorinated
solvents.

LINK: http://dx.doi.org/10.1021/es902595j