Kinetics of nitroaromatic reduction on granular iron in recirculating batch experiments
- Univ. of Waterloo, Ontario (Canada)
- Swiss Federal Inst. for Environmental Science and Technology, Duebendorf (Switzerland)
Granular iron has been determined to be a potentially useful reductant for the removal of common organic contaminants from groundwater. This research is aimed at improving the understanding of the processes that control the reactivity and longevity of the iron particles when they are used for groundwater treatment. A suite of nitroaromatic compounds (NACs) including 4-chloronitrobenzene, 2-methylnitrobenzene (2MeNB), and 2,4,6-trinitrotoluene (TNT) was used to investigate granular iron reactivity in anoxic pH 10, 0.008 M KNO{sub 3} solution. Master Builder`s brand of granular iron with a surface area of about 1 m{sup 2}/g was used in all experiments. The NACs were reduced rapidly to anilines that were found to sorb reasonably strongly to the solid particles and to interfere with the reduction of NACs. The granular iron was found to lose reactivity quite rapidly over the first few days of exposure and then more slowly over the next several months. Reactivity loss due to reversibly sorbed products was minimized by flushing the system with background electrolyte between experiments. Competition experiments with binary mixtures of 4ClNB and each one of the other NACs were performed to investigate relative affinities of these compounds for the solid surface. Despite the overall loss in reactivity observed for the granular iron, the relative rate constants in the competition experiments appeared to remain constant in time.
- OSTI ID:
- 642238
- Journal Information:
- Environmental Science and Technology, Vol. 32, Issue 13; Other Information: PBD: 1 Jul 1998
- Country of Publication:
- United States
- Language:
- English
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