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6939515 
Journal Article 
Degradation kinetics of hexachlorobenzene over zero-valent magnesium/graphite in protic solvent system and modeling of degradation pathways using density functional theory 
Garbou, AM; Liu, M; Zou, S; Yestrebsky, CL; , 
2019 
Yes 
Chemosphere
ISSN: 0045-6535
EISSN: 1879-1298 
PERGAMON-ELSEVIER SCIENCE LTD 
OXFORD 
195-204 
30708153 
WOS:000462109200024 
Hexachlorobenzene (HCB), like many chlorinated organic compounds, has accumulated in the environment from agricultural and industrial activity. Because of its health risks and adverse impact on various ecosystems, remediation of this contaminant is of vital concern. The objective of this study is to evaluate the proficiency of activated magnesium metal in a protic solvent system to accomplish reductive dechlorination of HCB. Experimental results were compared with those predicted by quantum chemical calculations based on Density Functional Theory (DFT). Multivariate analysis detected complete degradation of HCB within 30 min at room temperature, the reaction having a rate constant of 0.222 min(-1). Dechlorination was hypothesized to proceed via an ionic mechanism; the main dechlorination pathways of HCB in 1:1 ethanol:ethyl lactate were HCB -> PCBz -> 1,2,4,5-TCB; 1,2,3,5-TCB -> 1,2,4-TriCB; 1,3,5-TriCB -> 1,4-DiCB; 1,3-DiCB. The direct relationship between the decreasing number of CI substituents and dechlorination reaction kinetics agrees with the Delta G values predicted by the computational model. This methodology shows promise for the development of a practical and sustainable field application for the remediation of other chlorinated aromatic compounds. (C) 2019 Elsevier Ltd. All rights reserved.