講演情報
[8a-S103-2][Plasma Electronics Invited Talk] Characterization of Plasma-Treated Water via UV-Visible Absorption Spectroscopy: Technique and Scientific Meaning
Jin Hee Bae1, Jongchan Kim1, Seong-Cheol Huh1, Su-Jin Shin2, Wonho Choe1, 〇Sanghoo Park1 (1.Korea Advanced Institute of Science and Technology (KAIST), 2.2Agency for Defense Development (ADD))
キーワード：
Plasma-Treated Water、UV-Visible Absorption Spectroscopy、Deep Spectral Deconvolution
Reliable, time-resolved quantification of ozone (O3), nitrogen oxides (NOx = NO + NO2), and broader reactive oxygen and nitrogen species is pivotal to atmospheric-pressure plasma science, nitrogen-fixation applications, and air-quality research, yet progress has been hampered by diagnostics that are either too costly or too expertise-dependent. We introduce an automated broadband UV–visible absorption spectroscopy that couples a deep-learning deconvolution technique—Deep Spectral Deconvolution (DSD)—with a single optical path to extract eight overlapping gaseous species (O3, NO, NO2, NO3, N2O4, N2O5, HONO, and HONO2) and, through synchronized liquid-phase absorption, their aqueous derivatives (HNOy=2,3/NOy-) in plasma-treated water. The core of this platform is Deep Spectral Deconvolution (DSD) model that is based on a deep learning-based deconvolution strategy with a multi-objective loss function. This architecture learns both numerical features (e.g., peak positions and widths) and graphical trends directly from 2D dynamic spectral images, eliminating empirical fitting processes and post-data processing including manual noise masking. The method is validated in two representative studies: (i) equilibrium shifts between the standard NO2 and N2O4, where measured concentrations match thermodynamic predictions; and (ii) a surface dielectric-barrier discharge operated in controlled atmospheres above distilled water, where real-time tracking reveals that lower O2 fractions accelerate conversion from O3/NO3 to NO/NO2 and selectively yield nitrite-rich plasma-treated water, whereas higher O2 sustains nitrate-dominant, acidic conditions.