Interphase mass transfer during chemical oxidation of TCE DNAPL in an aqueous system

摘要

The chemical oxidation of trichloroethene dense non-aqueous phase liquid by permanganate was studied in an aqueous system using micro-reaction/extraction vessels in a novel approach. Experiments were conducted at ambient temperature (～20℃) under static and mixed conditions to evaluate the rate of TCE_(DNAPL) dissolution as a function of permanganate concentration. Chemical oxidation by permanganate was shown to increase the rate of TCE_(DNAPL) dissolution under static conditions and decrease the rate of dissolution under mixed conditions. The apparent inconsistency in results appears to result from the local deposition of a film at the DNAPL interface composed of manganese oxide solids as discovered through visual observation with the aid of a Goniometer. Data from interfacial deposition experiments suggest that the film formed rapidly and reached maturation within approximately 2 h with little or no growth occurring thereafter. A conceptual model of the reaction and mass transfer processes occurring at the DNAPL interface was proposed based on the experimental results.