Reaction mechanisms for the dechlorination of chlorobenzenes present in
selected South Africa water systems
M.M. Magu*, P.P. Govender, & J.C. Ngila
Department of Applied Chemistry, University of Johannesburg, P. O. Box 17011 Doornfontein, 2028,
Johannesburg, South Africa;
* magujnr@gmail.com;
Abstract
Drinkable water maybe contaminated from both organic and inorganic compounds from either point or nonpoint sources of pollutants [1]. When this happens, the water is no longer safe for drinking. Presence of
chlorinated organic compounds (COCs) in water poses great dangers since they persist in the environment
and are associated with adverse health effects including cancer, reproductive and developmental toxicity
and endocrine disruption [2]. These chlorinated organic compounds pose great danger to aquatic
organisms as well as animals including human beings [3].
This study focuses on specific chlorinated organic compounds listed in Fig. 2 and how they interact to form
complexes with some selected metal ions present in surface water and treated water systems in South
Africa [4]. Samples from different water systems were collected and used to qualitatively determine the
presence of chlorinated organic compounds [5].
Volatile organic compounds were analysed using the Gas Chromatograph Time of Flight mass spectrometer
(GCxGC – TOF/MS [6-8]. Reaction mechanisms of the complexes was done with Gaussian 09 and
GaussView 5 [9, 10]. Proposed reaction mechanism [11] for one of the chlorobenzene is shown in Fig. 1.
Figure 1: Proposed dechlorination reaction mechanisms for pentachlorophenol
B
A
C
D
Figure 2: A=Pentachlorophenol; B=1,2,3-Trichlorobenzene; C=1,2,4-Trichlorobenzene; and D=1,2,4Trichlorobenzene
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