Atmospheric Pressure Plasma in Contact with High-speed Water Flow for Evaluating Liquid-phase OH Transport

Novel applications of non-equilibrium atmospheric pressure plasmas (APPs) in a liquid or in contact with a liquid have been found in the life science field. However, much of the reactive species chemistry at the plasma-liquid interface has not been understood. Notably, short-lived species (e.g., OH_aq, N_xO_yaq, HO_2aq) has hardly characterized due to their high reactivity and non-uniformity. To break through this problem, we built an APP system with a high-speed liquid flow (over 10 m/s) through plasma. This APP system revealed very rapid OH_aq decay within approximately 0.5 ms after the plasma exposure [1]. To explain the rapid decay of OH_aq , we built the numerical model which assumed highly surface localized distribution of OH_aq and it is consumed by the reaction with OH_aq , H₂O_2aq, and NO₂⁻_aq. As a results, OH_aq decay calculated using the numerical model was in good agreement with the experimental rapid decay.

In this presentation, we would like to discuss the detail comparison between experimental and numerical modeling results.