engleski

Gas/Liquid Hybrid Electrical Discharge Reactors for the Degradation of Organic Dyes and Phenol in Water

Hybrid gas/liquid electrical discharge reactors involve simultaneous high voltage electrical discharges in water and in the gas phase above the water surface. Two types of pulsed corona reactors, the hybrid-series and the hybrid-parallel, have recently been developed and tested in our laboratory. The hybrid-series reactor utilizes a high voltage needle point electrode immersed directly in the water phase while the ground electrode (made of reticulated vitreous carbon, RVC) is placed in the gas phase above the water surface. This electrode configuration leads to relatively intense plasma channels between the surface of the liquid and the ground electrode in the gas phase. The hybrid-parallel reactor utilizes a high voltage electrode (made of RVC) in the gas phase above the water in conjunction with the high voltage needle electrode immersed in the water. The ground electrode, also made of RVC, is placed at the interface between the gas and liquid phase. The gas phase plasma in this case resembles conventional gas phase corona discharge. In both reactor types the liquid phase discharge resembles that observed in previous work with direct discharge in the water. In previous work we have measured the rates of formation of ozone and hydrogen peroxide and have found that the rates of formation of hydrogen peroxide in the two hybrid reactors are the same as in a reference reactor configuration where no gas phase discharge occurs. We have also shown that the concentration of ozone in the hybrid-parallel reactor is ten times higher than in the hybrid-series reactor, while no measurable ozone is formed in the reference case. The parallel reactor was found to be more efficient than the other two reactors in the degradation of nitrophenol. The current work focuses on the degradation of phenol and one type of azo dye, reactive blue 137, in the three reactors with and with the addition of zeolite catalysts in the liquid phase. Experiments have been conducted to assess the effectiveness of the various reactor configurations on the dye decolorization and the phenol oxidation. In addition, these experiments contribute to our understanding of the various reactive species formed in the different hybrid reactor configurations, and to the evaluation of the effects of several types of zeolites including H/Y, Na/Y, ZSM-5, and Fe-ZSM-5 on the organic contaminant removal.

hybrid corona reactors; dye removal; phenol; degradation; zeolites

nije evidentirano