REDUCTIVE DEHALOGENATION OF TRICHLOROETHYLENE - KINETIC-MODELS AND EXPERIMENTAL-VERIFICATION

This paper develops a generalized kinetic model for two-phase systems involving reactions in one phase with product partitioning into a seco nd phase, and applies it to the reductive dehalogenation of trichloroe thylene using two systems. The generalized approach can be used for a variety of catalyst choices, including zero-valent metals. With vitami n B-12, the model includes specific reaction pathways for the reductiv e dehalogenation of TCE combined with the partitioning of reactants, i ntermediates, and products between the gas and liquid phases. The mode l has been used to study the effect of various parameters on the proce ss effectiveness, which otherwise are very difficult to conceive throu gh experimental analysis. In the case of zero-headspace system with ze ro-valent iron, sorption effects are included to incorporate the parti tioning onto the solid surface. A new parameter, 'fractional active si te concentration' is introduced to incorporate the differences in reac tive and nonreactive sites on the iron surface, which affects the degr adation performance. The generalized model has important implications for kinetic modeling, monitoring of VOCs and their degradation product s, and design and selection of remediation technologies for such mater ials. The model predictions have been verified with our experimental d ata and the results from the Literature. (C) 1998 Published by Elsevie r Science B.V. All rights reserved.