Molecular fragmentation: statistical model and acetone plasma abatement with product on-line identification

Molecular fragmentation is a promising technique for the treatment of polluted gaseous effluents. This work deals with the theoretical and experimental study of the reduction of VOC chemical pollutants by fragmentation. We have transformed an atomic nucleus and cluster fragmentation model, redesign at CSNSM, into a model that treats any type of molecules (SMF model). The efforts have been focused on accelerating the computation of the weights with multivariate incomplete Beta functions (factor 30 on speed), on the interfacing with the Gaussian ab-initio software, on the generalization of the molecular formalism as well as on molecular rearrangements. To account for the characteristics of our experimental setup (reactivity between fragmentation and detection) the results were processed by a 0-D chemical kinetics model. Predictions on acetone fragmentation were then compared to our experimental results obtained using an innovative device. Acetone degradation was carried out in a homogeneous plasma reactor, developed at LPGP, to guarantee the uniformity of the reaction conditions. To measure the large number of discharge by-products, we used a new detection method developed at LCP: compact FT-ICR mass spectrometers producing in situ real-time measurements. This new experimental device has been successfully implemented. It allowed the fine study of the acetone excitation - de-excitation - oxidation mechanisms and the validation of the theoretical predictions. (author)