Modeling Perchloroethylene Reduction in Zero-Valent Metal System Using Mathematical Method

Abstract

The dechlorination of perchloroethylene (PCE) in aqueous solution is significant for the decontamination of water. Previous study based on batch tests was conducted on the degradation of PCE using zero-valent metal. The degradation reaction fit well with pseudo-first-order kinetic model. In this study a hypothesized reaction sequence for reduction of chlorinated ethylene and related compounds was presented to describe the reticulation degradation pathway of PCE. Mathematical model was developed to predict the subsequent degradation of PCE and intermediates; results showed that 170 days were needed to transform all of PCE to non-chlorinated hydrocarbons in degradation reactors contained zero-valent iron, while 240 days were needed for zero-valent zinc. The variation of each species probably occurred in degradation process were also predicted, and the intermediates showed the same variation tendency of increasing in the first stage, reaching to peak value, and then decreasing in later period.