Comparative Study On Dye Decolorization By Underwater Corona Discharge

Underwater corona discharge is found to be a good kind of wastewater treatment technology in these years. It has lots of advantages as no selectivity, high efficiency, no secondary pollution and so on. Resently, water treatment device with large volume and low energy consumption has received extensive attention. We have developed a coaxial rod-to-cylinder electrode system. It takes a stainless steel rod with3mm in diameter and60mm in long as the anode, and a stainless steel mesh with44mm in diameter and65mm in long as the cathode. The stainless steel rod electrodes is covered with a insulated pipe of0.4mm in thickness. There are a series of slits on the pipe spaced about4mm with each other and20-80μm in width. Under the high voltage pulse, streamer discharge can be formed from the slits randomly pointing the stainless steel cathode. Decolorize the dyes of sunset yellow and brilliant blue with the rod-to-cylinder electrode system. The decolorization rate and energy consumption are quantitative analyzed. Also, the effect of the solution condition on the decolorization rate and energy consumption are investigated. Compared with the rod-to-cylinder electrode system, it is easy to find the superiority to the pin-to-cylinder one. Main findings are as followed:(1) The solution conductivity has little effect on decolorization rate.(2) The decolorization rate decreases and the energy consumption increases with increasing the pH value.(3) The decolorization rate increases with increasing the frequency, and it’s faster than linear growth.(4) The energy consumption increases with increasing the solution conductivity and pH value.(5) The decolorization rate constant for the sunset yellow solution is higher and the energy consumption is lower than that for the brilliant blue.(6) Fixing the pH value at7.8, the frequency at600Hz, the degradation rate constant for the rod-to-cylinder one is about3times larger than that for the pin-to-cylinder one. The energy consumption is lower for the rod-to-cylinder one.(7) Fixing the solution conductivity at150μS/cm, the frequency at600Hz, the degradation rate constant decreases with increasing the solution pH value, but the rod-to-cylinder one decreases faster. The energy consumption increases with increasing the solution pH value,but it is significantly lower in the rod-to-cylinder one when the solution pH <8, when the solution pH=10, they are nearly the same.