Ultrasonics Sonochemistry ( IF 8.7 ) Pub Date : 2022-11-28 , DOI: 10.1016/j.ultsonch.2022.106250 Younggyu Son 1 , Jongbok Choi 2
The sonochemical generation of NO2− and NO3− is considered to be one of the reasons for the low sonochemical oxidation activity in the presence of N2 in the liquid phase. In this study, the generation characteristics of NO2− and NO3− were investigated using the same 28 kHz sonoreactor and the 12 gas conditions used in Part I of this study. Three gas modes, saturation/closed, saturation/open, and sparging/closed, were applied. N2:Ar (25:75), N2:Ar (50:50), and O2:N2 (25:75) in the saturation/closed mode generated the three highest values of NO2− and NO3−. Ar and O2 were vital for generating relatively large concentrations of NO2− and NO3−. The absorption of N2 from the air resulted in high generation of NO2− and NO3− for Ar 100 % and Ar/O2 mixtures under the saturation/open mode. In addition, gas sparging enhanced the generation of NO2− and NO3− for N2:Ar (25:75), O2:N2 (25:75), and N2 significantly because of the change in the sonochemically active zone and the increase in the mixing intensity in the liquid phase, as discussed in Part I. The ratio of NO3− to NO2− was calculated using their final concentrations, and a ratio higher than 1 was obtained for the condition of Ar 100 %, Ar/O2 mixtures, and O2 100 %, wherein a relatively high oxidation activity was detected. From a summary of the results and findings of previous studies, it was revealed that the observations of NO2− + NO3− could be more appropriate for investigating the NO2− and NO3− generation characteristics. In addition, H2O2/NO2−/NO3− related activity rather than H2O2 activity was suggested to quantify the OH radical activity more appropriately in the presence of N2.
中文翻译：
开放和封闭系统中气体饱和度和鼓泡对声化学氧化活性的影响，第二部分：NO2−/NO3− 的生成和简短的批判性评论
NO 2 -和NO 3 -的声化学生成被认为是在液相中存在N 2的情况下声化学氧化活性低的原因之一。在本研究中，使用本研究第一部分中使用的相同 28 kHz 声反应器和 12 种气体条件研究了 NO 2 -和 NO 3 -的生成特性。应用了三种气体模式：饱和/封闭、饱和/开放和喷射/封闭。饱和/封闭模式下的N 2 :Ar (25:75)、N 2 :Ar (50:50) 和O 2 :N 2 (25:75) 产生NO 2 -和NO 3 -的三个最高值。 Ar和O 2对于产生相对高浓度的NO 2 -和NO 3 -至关重要。在饱和/开放模式下，Ar 100 %和Ar/O 2混合物从空气中吸收N 2导致大量产生NO 2 -和NO 3 - 。此外，由于声化学活性的变化，气体喷射显着增强了N 2 :Ar (25:75)、O 2 :N 2 (25:75)和N 2的NO 2 -和NO 3 -的生成。区和液相混合强度的增加，如第一部分中讨论的。 利用最终浓度计算NO 3 -与NO 2 -的比率，对于Ar 100 %、Ar/O 2混合物和O 2 100 %的条件，获得高于1的比率，其中相对较高的氧化检测到活动。总结之前的研究结果和发现，发现NO 2 - + NO 3 -的观测可能更适合研究NO 2 -和NO 3 -的生成特性。此外，建议使用H 2 O 2 /NO 2 - /NO 3 -相关活性而不是H 2 O 2活性来更合适地量化N 2存在下的OH自由基活性。
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