Do Ultrafine Bubbles Work as Oxygen Carriers?
Do Ultrafine Bubbles Work as Oxygen Carriers?
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DOI：
10.1021/acs.langmuir.2c01209
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发表时间：
2023-01-17
期刊：
影响因子：
3.9
通讯作者：
Takeoka，Shinji
中科院分区：
文献类型：
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作者：
Kakiuchi，Kenta;Kozuka，Tomoki;Takeoka，Shinji
微细气泡（FB）是指尺寸小于100 μm的气泡，根据其尺寸分为超细气泡（UFB，< 1 μm）和微气泡（MB，1-100 μm）。虽然FB曝气被认为是一种比大气泡曝气更有效的方式来增加无氧水中的氧含量，但很少有报道表明分散的UFB是否作为氧载体工作。此外，氧过饱和度是FB分散体的吸引人的特征之一，但其原因尚待揭示。在这项研究中，我们评估的FBs，特别是UFB浓度，和氧含量之间的关系在几种情况下，揭示这两个问题。分别使用颗粒分析仪和我们开发的氧气测量方法来检测FB浓度和氧气含量，该方法可以测量FB分散体中的氧气含量。首先，在相对于周围氧水平的来自UFB的氧分散的评价中，UFB即使在脱气水中也没有变小或减少。第二，评价了UFB和氧含量在储存温度和储存期间盖的存在下的变化，并且它们之间没有相关性。这意味着UFB对UFB分散体中的氧含量贡献很小。此外，在UFB分散体中的氧含量随着时间的推移而降低，与具有少量UFB的氧过饱和水的氧含量相同。第三，我们通过同时测量FB浓度和氧气含量来评估FB生成过程中两者之间的关系。结果表明，分散MB和UFB浓度不占FB分散的过饱和度。结果表明，100-200 nm的超细纤维本身并不作为氧载体，而FB分散液中氧的过饱和是由于FB生成过程中溶解氧的过饱和状态所致。
Fine bubbles (FBs) are bubbles with sizes less than 100 μm and are divided into ultrafine bubbles (UFBs, < 1 μm) and microbubbles (MBs, 1–100 μm) depending on their size. Although FB aeration is known as a more efficient way than macrobubble aeration to increase the oxygen level in unoxygenated water, few reports have demonstrated whether dispersed UFBs work as oxygen carriers or not. Furthermore, oxygen supersaturation is one of the attractive characteristics of FB dispersion, but the reason is yet to be revealed. In this study, we evaluated the relationship between the FBs, especially UFB concentration, and oxygen content in several situations to reveal the two questions. The FB concentration and oxygen content were examined using particle analyzers and our developed oxygen measurement method, which can measure the oxygen content in FB dispersion, respectively. First, in the evaluations of the oxygen dispersion from UFBs with respect to the surrounding oxygen level, UFBs did become neither small nor diminish even in degassed water. Second, the changes in UFBs and oxygen content upon storage temperature and the existence of a lid during storage were evaluated, and there was no correlation between them. It means UFBs contribute little to the oxygen content in UFB dispersion. Furthermore, the oxygen content in the UFB dispersion decreased over time identically as that of the oxygen-supersaturated water with little UFBs. Third, we evaluated the relationship between FB concentration and oxygen content during FB generation by measuring them simultaneously. The results showed that dispersed MB and UFB concentrations did not account for the supersaturation of the FB dispersion. From the result, it was revealed that 100–200 nm of UFBs themselves did not work as oxygen carriers, and the oxygen supersaturation in FB dispersions was due to the supersaturated state of dissolved oxygen that was prepared during the FB generation process.