DESTRUCTION OF AQUEOUS SOLUTIONS OF 2,4-DICHLOROPHENOL IN A PLASMA-CATALYTIC BARRIER DISCHARGE REACTOR

In this work, the processes of destruction of aqueous solutions of 2,4-dichlorophenol in a dielectric barrier discharge of atmospheric pressure in an oxygen atmosphere with a Pt/Al2O3 catalyst located inside the reactor were investigated. It has been shown experimentally that 2,4-dichlorophenol is destroyed in plasma quite efficiently (the degree of destruction reaches at least 70%). In this work, the kinetic parameters the destruction process were estimated and the main intermediate and final products of the decomposition of 2,4-dichlorophenol under the action of active plasma particles in the presence of a catalyst were determined. The destruction of the starting compound is described by a kinetic equation of the first order on the concentration of 2,4-dichlorophenol. The effective rate constant weakly depends on the experimental conditions and it was equal to 0.43 s(-1). The composition of the destruction products was studied by gas chromatography, as well as by fluorescence, spectrophotometric, and potentiometric methods. Cl- in the liquid phase, as well as CO2 in the gas phase, were identified as the end products of destruction, and the intermediate products of destruction are carboxylic acids and aldehydes, but their concentrations are low relative to carbon dioxide. Molecular chlorine was not detected in the gas phase. It was found that ozone does not make a significant contribution to the oxidative degradation of 2,4-dichlorophenol, while other active plasma particles, for example, hydroxyl radicals and atomic oxygen, play the main role in the oxidation process.