Hydrodynamics and mass transfer investigations in a biphasic plasma reactor

Abstract

Abstract This work aims to investigate the radical mechanism responsible for the degradation of a highly soluble pollutant in water. The AG25 dye was chosen as substrate and the GAD-Spray as biphasic reactor to treat it remotely. The study is conducted through experiments and simulations using Comsol Multiphysics-chemical engineering module. The Hydrodynamics coupled with the plasma-reaction has demonstrated that a low mass transfer in the droplet favorites the removal of the pollutant. It indicates that the plasma-reactions take place at the stagnant liquid film are far from the bulk of the droplet. Numerical modeling fitted by the conversion rate of the reagent has shown that the peroxynitrous acid HOONO (PON) is responsible for the degradation of AG25 in water. Consequently, and according different kinetic mechanisms, a radical mechanism has been predicted based on this deduction. The removal and the degradation rates were of 88 and 83% respectively during 90 min after the plasma exposure. The results of simulations showed a significant agreement between the calculated and the real removal rate of AG25. Through this study, it can be confirmed that GAD-spray-tower plasma reactor is efficient to eliminate and degrade remotely a very soluble pollutant through the HOONO (PON) plasma long-lived species.