Kinetics of contaminant degradation by permanganate.
To provide a more complete understanding of the kinetics of in situ chemical oxidation (ISCO) with permanganate (MnO4-), we measured the kinetics of oxidation of 24 contaminants-many for which data were not previously available. The new data reported here were determined using an efficient method based on continuous measurement of the MnO4- concentration by absorbance spectrometry. Under these conditions, the kinetics were found to be first-order with respect to both contaminant and MnO4- concentrations, from which second-order rate constants (k") were readily obtained. Emerging contaminants forwhich k" was determined (at 25 degrees C and pH 7) include 1,4-dioxane (4.2 x 10(-5) M(-1) s(-1)), methyl t-butyl ether (MTBE) (1.0 x 10(-4) M(-1) s(-1)), and methyl ethyl ketone (MEK) (9.1 x 10(-5) M(-1) s(-1)). Contaminants such as 2,4,6-trinitrotoluene (TNT), the pesticides aldicarb and dichlorvos, and many substituted phenols are oxidized with rate constants comparable to tetrachloroethene (PCE) and trichloroethene (TCE) (i.e., 0.03-1 M(-1) s(-1)) and therefore are good candidates for remediation with MnO4- in the field. There are several--sometimes competing--mechanisms by which MnO4- oxidizes contaminants, including addition to double bonds, abstraction of hydrogen or hydride, and electron transfer.
Waldemer
Rachel H
RH
Department of Environmental and Biomolecular Systems, OGI School of Science and Engineering, Oregon Health and Science University, 20000 NW Walker Road, Portland, Oregon 97006, USA.
Tratnyek
Paul G
PG
D004785:Environmental Pollutants; D007700:Kinetics; D017895:Manganese Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D010575:Pesticides / Q000737:chemistry; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry
D004785:Environmental Pollutants; D017895:Manganese Compounds; D010087:Oxides; D010575:Pesticides; D011084:Polycyclic Aromatic Hydrocarbons; C048856:permanganic acid