Phenol Degradation In Aqueous Solution By Pulsed Streamer Discharge Combined With TiO₂ Photocatalyst

Active species like OH radicals, H₂O₂, et al could be generated in gas-liquid pulsed streamer system, and strong UV radiation appeared simultaneously. In order to elementarily discuss the role of UV radiation in degradation organic comounds solution. Photocatalyst like TiO₂ was added into the multi-needle-to-plate gas-liquid discharge system which was supplied with a short and positive pulsed high-voltage power. In this system pulsed discharge streamer was used as the lamp-house to induce the catalysis activity of nanometer TiO₂ photocatalyst in plasma. And the synergistic effects of photocatalysis and pulsed discharge plasma were used to improve the degradation rate of difficult biodegradation organics. The effects of factors such as peak voltage, bubbling quantity, electrodes distance, and solution conductivity on the formation of streamer, and the effects of degradation pH and the diameter of TiO₂ on phenol were investigated. And the reaction mechanism of phenol degradation was elementarily discussed.The results of this experimental study are summarized as follows.â‘ The ultraviolet streamer produced by pulsed discharge could induce the photocatalysis activity of TiO₂ and therefore improve the phenol degradation rate. The 250mL phenol solution with initial concentration of 100mg/L and with conductivity of 100μS/cm was used as the simulated organic Wastewater. In experiments, TiO₂ (P25) was added into the simulated Wastewater with an quantity of 0.4g/L, and then the phenol solution was treated for 60min by high-voltage pulsed with a magnitude of 20kV and the repetition frequency of 50Hz. TiO₂ photocatalyst played little role in phenol removal when pulsed power wasn't supplied, the adsorption efficiency of catalyst on phenol was less than 1%. Compared with the degradation rate of phenol only by pulsed discharge, the removal rate phenol was increased by 8% when TiO₂ was added into the pulsed streamer discharge system, the degradation rate of phenol was 95.2%. The analysis of XRD and TEM indicated that the component of TiO₂ (P25) was appreciably changed and particles were agglomeration after discharge.â‘¡The addition quantity of TiO₂ had effect on the phenol degradation, the phenol degradation rate increased with TiO₂ additon from 0-0.4g/L, but the degradation rate decreased after TiO₂ addition quantity was beyond 0.4g/L. In our experimental system, the most suitable quantity was 0.4 g/L.