engleski

The Degradation of Organic Compounds by Aqueous Phase Pulsed Corona Discharge

Recent experimental studies have demonstrated the utility of pulsedcorona discharge reactors for the oxidative degradation of low concentrations of organic compounds dissolved in water. A pulsed corona discharge is produced in the aqueous phase using a high voltage (35 to 50 kV) electrical field and a capacitor discharge with energies of approx. 1J/pulse. In our previous studies, both the high voltage needle electrode and the ground plate electrode were immersed in the liquid phase. In this configuration, it was demonstrated that significat quantities of hydrogen peroxide are produced directly in the liquid phase. The hydrogen peroxide, in combination with dissolved iron salts, leads to the Fenton reaction for the generation of hydroxyl radicals and subsequent oxidation of the organic waste compounds. Furthermore, when the ground electrode is made of reticulated vitreous carbon (RCV) and is placed in the gas phase above the liquid surface, corona discharge is simultaneously produced in the gas and the liquid phases. In this configuration, ozone is produced in the gas while hydrogen peroxide is produced in the liquid. The combined effects of ozone and hydrogen peroxide lead to further hydroxyl radical generation through the Peroxone process. Control of the relative amounts of hydrogen peroxide and ozone can be accomplished through variation of the electrical field conditions of the discharge and recirculation and sparging of the gas through the liquid. Our recent work has focussed on the application of pulsed corona discharge for the degradation of small organic compounds such as phenol, with and without suspended activated carbon particles. The activated carbon particles serve as both adsorbents and potential catalytic surfaces. Additional studies with more complex organic compounds, including various organic dyes, have been conducted with and without suspended catalytic zeolite particles. In this presentation, we summarize our findings with respect to reaction mechanisms and energy costs for removal of these organic compounds in the pulsed corona reactor.

Organic compounds; degradation; AOP; pulsed corona discharge

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