Optical density inferences in aqueous solution with embedded micro/nano bubbles: A reminder for the emerging green bubble cleantech
Optical density inferences in aqueous solution with embedded micro/nano bubbles: A reminder for the emerging green bubble cleantech
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DOI：
10.1016/j.jclepro.2021.126258
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发表时间：
2021-02
影响因子：
11.1
通讯作者：
W. Fan;Pratik Desai;W. Zimmerman;Y. Duan;J. Crittenden;Chunliang Wang;M. Huo
中科院分区：
文献类型：
--
作者：
W. Fan;Pratik Desai;W. Zimmerman;Y. Duan;J. Crittenden;Chunliang Wang;M. Huo
微纳气泡作为一种环境友好的清洁技术，在清洁生产和提高水的可再生性方面越来越多地被用于污染控制，许多工作都使用光密度(OD)来代替液体样品中化学/生物物质的浓度。本研究报告了MNBs会引起相当大的光散射，并影响液体样品的测得光密度。实验结果表明，在常用的生物培养介质和去离子水中，气泡曝气可使300~600 nm波长的OD值增加0.14~0.50。落在有效前向范围之外的散射光增加了外径，这种增加依赖于气泡的大小和光的波长。Mie计算表明，较小气泡的散射越强，OD增加越多。通过定义外径偏差&0.01，利用开普勒猜想和比尔-朗伯定律计算了气泡尺寸的临界阈值。对于常用的600 nm波长，只有直径为>；263μm的水中气泡的外径增加可以忽略不计。时域有限差分模拟显示了气泡附近高度不均匀的电场，并验证了在较短波长下具有较高的散射效率。通过短期超声波对MNB系统中的样品进行消泡，消除了光散射。这项工作的发现描绘了MNBs的光学性质，强调了由此对光学测量的影响，并提出了水处理中的消泡方法。
As an environmental friendly cleantech, micro/nano bubbles (MNBs) have been increasingly used for pollution control in cleaner production and water renewability improvement, and many works used optical density (OD) as proxy for the concentration of chemical/biological substances in liquid samples. This study reported that MNBs induced considerable light scattering and impacted the measured OD of liquid samples. The experimental results showed that bubble aeration increased the OD at wavelengths of 300–600 nm by 0.14–0.50 in commonly used bio-cultural medium and deionized water. The scattered light that fell outside the effective forward range increased the OD, and this increase was dependent on the bubble size and light wavelength. The Mie calculations showed that the scattering of smaller bubble is stronger and results in more OD increase. By defining the OD deviation <0.01, the critical thresholds of bubble size were calculated using the Kepler conjecture and Beer-Lambert’s law. For the commonly used wavelength 600 nm, the OD increase can be neglected only for bubbles with diameter >263 μm in water. The finite-difference time-domain simulation illustrated the highly nonuniform electric field near the bubble, and verified the higher scattering efficiencies at shorter wavelength. De-bubbling samples from MNB systems via short-term sonication eliminated light scattering. Findings from this work delineated the optical properties of MNBs, highlighted resulting impact on optical measurement and proposed a de-bubbling method in water treatment.