| Title: | Evaluation of the kinetic oxidation of aqueous volatile organic compounds by permanganate |
| Author(s): | Mahmoodlu MG; Hassanizadeh SM; Hartog N; |
| Address: | "Utrecht University, Department of Earth Sciences, The Netherlands. Electronic address: m.gharehmahmoodlu@uu.nl. Utrecht University, Department of Earth Sciences, The Netherlands; Soil and Groundwater Systems, Deltares, Utrecht, The Netherlands. Utrecht University, Department of Earth Sciences, The Netherlands; KWR Watercycle Research Institute, Nieuwegein, The Netherlands" |
| DOI: | 10.1016/j.scitotenv.2013.11.066 |
| ISSN/ISBN: | 1879-1026 (Electronic) 0048-9697 (Linking) |
| Abstract: | "The use of permanganate solutions for in-situ chemical oxidation (ISCO) is a well-established groundwater remediation technology, particularly for targeting chlorinated ethenes. The kinetics of oxidation reactions is an important ISCO remediation design aspect that affects the efficiency and oxidant persistence. The overall rate of the ISCO reaction between oxidant and contaminant is typically described using a second-order kinetic model while the second-order rate constant is determined experimentally by means of a pseudo first order approach. However, earlier studies of chlorinated hydrocarbons have yielded a wide range of values for the second-order rate constants. Also, there is limited insight in the kinetics of permanganate reactions with fuel-derived groundwater contaminants such as toluene and ethanol. In this study, batch experiments were carried out to investigate and compare the oxidation kinetics of aqueous trichloroethylene (TCE), ethanol, and toluene in an aqueous potassium permanganate solution. The overall second-order rate constants were determined directly by fitting a second-order model to the data, instead of typically using the pseudo-first-order approach. The second-order reaction rate constants (M(-1) s(-1)) for TCE, toluene, and ethanol were 8.0x10(-1), 2.5x10(-4), and 6.5x10(-4), respectively. Results showed that the inappropriate use of the pseudo-first-order approach in several previous studies produced biased estimates of the second-order rate constants. In our study, this error was expressed as a function of the extent (P/N) in which the reactant concentrations deviated from the stoichiometric ratio of each oxidation reaction. The error associated with the inappropriate use of the pseudo-first-order approach is negatively correlated with the P/N ratio and reached up to 25% of the estimated second-order rate constant in some previous studies of TCE oxidation. Based on our results, a similar relation is valid for the other volatile organic compounds studied" |
| Keywords: | "Environmental Restoration and Remediation/*methods Groundwater/chemistry Kinetics Manganese Compounds/*chemistry *Models, Chemical Oxidation-Reduction Oxides/*chemistry Volatile Organic Compounds/analysis/*chemistry Water Pollutants, Chemical/analysis/*ch;" |
| Notes: | "MedlineMahmoodlu, Mojtaba G Hassanizadeh, S Majid Hartog, Niels eng Evaluation Study Research Support, Non-U.S. Gov't Netherlands 2013/12/03 Sci Total Environ. 2014 Jul 1; 485-486:755-763. doi: 10.1016/j.scitotenv.2013.11.066. Epub 2013 Dec 2" |
