Vol. 12, No.1, pp.30--36 (2018)
Numerical and Experimental Investigation of Acetic Acid Decomposition by a Nano-Pulse Discharged Bubble in Water
Y. He, S. Uehara, H. Takana, and H. Nishiyama
Institute of Fluid Science, Tohoku University, Japan
Nano-pulse discharges in bubbles are regarded as an efficient method to generate plasma for decomposition of persistent organic pollutants (POPs) in water. In this study, decomposition experiments of acetic acid solution by multiple nano-pulse discharged bubbles were firstly conducted for different voltages and frequencies under the same input power. It is found that the concentration of acetic acid solution decreased most for lower applied voltage and higher frequency. Moreover, a two-dimensional r-θ numerical model was constructed to investigate the decomposition characteristics of acetic acid by a nano-pulse discharged bubble. Hydroxyl radicals (·OH) with high oxidation potential were generated in bubbles to decompose POPs. They were found to be able to diffuse through the bubble interface to several micrometers in water. The results showed that acetic acid were decomposed by OH radicals. The average decomposition rate was dependent on the water layer thickness. It is also found that for a given input power, acetic acid were mostly decomposed for lower applied voltage and higher frequency. The numerical results showed qualitative consistency with the experimental results.
Keywords - Water treatment, nano-pulse discharged bubble, hydroxyl radicals, acetic acid decomposition