Aeration and dissolution behavior of oxygen nanobubbles in water

Xue, Shan; Zhang, Yihan; Marhaba, Taha F.; Zhang, Wen

doi:10.1016/j.jcis.2021.11.061

Cited by 30 publications

(20 citation statements)

References 49 publications

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“…(6) (7) or (8) The equation of the state for the real gas can be expressed as follows: (9) where P BO is the gas pressure at R 0 . From the charge conservation, the surface charge density can be written as follows: (10) Upon substitution eq 7 can be rewritten as follows: (11) or (12) where (13) The inverse of the roots of the cubic equation (eq 12) for a range of value of α, β, and ζ have been plotted in Figure 8 for a fixed value of α and range of values of β and ξ. The surface charge density is calculated by the zeta potential and size of nanobubbles using the Debye−Huckel approximation (…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Nanobubbles has gained significant attention from both applied and fundamental research viewpoints in recent times. − Nanobubble encompasses a wide range of applications, particularly toward the 21 st century grand challenges such as water technology, − food sector, , health technology, − energy sectors, energy efficient aeration, surface cleaning, disinfection and sanitization, mineral flotation, ultrasound contrast agent, drag reduction, drug delivery and smart medicine, , tumor hypoxia, etc. Despite numerous applications, the fundamental of the nanobubbles is under infancy.…”

Section: Introductionmentioning

confidence: 99%

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On Nanobubble Dynamics under an Oscillating Pressure Field during Salting-out Effects and Its DLVO Potential

et al. 2023

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We have investigated the origin, stability, and nanobubble dynamics under an oscillating pressure field followed by the salting-out effects. The higher solubility ratio (salting-out parameter) of the dissolved gases and pure solvent nucleates nanobubbles during the salting-out effect, and the oscillating pressure field enhances the nanobubble density further as solubility varies linearly with gas pressure by Henry’s law. A novel method for refractive index estimation is developed to differentiate nanobubbles and nanoparticles based on the scattering intensity of light. The electromagnetic wave equations have been numerically solved and compared with the Mie scattering theory. The scattering cross-section of the nanobubbles was estimated to be smaller than the nanoparticles. The DLVO potentials of the nanobubbles predict the stable colloidal system. The zeta potential of nanobubbles varied by generating nanobubbles in different salt solutions, and it is characterized by particle tracking, dynamic light scattering, and cryo-TEM. The size of nanobubbles in salt solutions was reported to be higher than that in pure water. The novel mechanical stability model is proposed by considering both ionic cloud and electrostatic pressure at the charged interface. The ionic cloud pressure is derived by electric flux balance, and it is found to be twice the electrostatic pressure. The mechanical stability model for a single nanobubble predicts the existence of stable nanobubbles in the stability map.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On Nanobubble Dynamics under an Oscillating Pressure Field during Salting-out Effects and Its DLVO Potential

et al. 2023

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“…We investigated the influence of UFBs on the oxygen content from several experiments, and the results showed that the contribution of UFBs to the oxygen content in FB dispersion is small. There are many studies on oxygen supply from FBs in terms of mass transfer, which evaluate oxygen diffusion from FBs to unoxygenated water. ,,− Although these approaches are extremely important in FB research, experimental data are insufficient to substantiate the theory for applying to UFBs. We thought it is because the theories include the Laplace pressure of floating UFBs, which has not been experimentally obtained in the calculations.…”

Section: Resultsmentioning

confidence: 99%

“…While there are some experiments monitoring dissolved oxygen with probe-type oxygen electrodes in large containers where FBs generate, it is difficult to conduct a small-scale experiment that allows precise management of experimental conditions. Furthermore, some papers suggested that the adhesion of bubbles to the electrode surface is an important issue when using probe-type oxygen electrodes that are used for a quick and easy method to measure dissolved oxygen in water. , Therefore, we developed a novel method for measuring the oxygen content in FB dispersions that satisfied the criteria of accuracy, ease (four steps), small sample volume (50–500 μL), and quickness (<8 min) without the adhesion issue . Moreover, FB dispersion at 20 °C has oxygen above 50 mg/L, and our method can measure the range that cannot be measured with probe-type dissolved oxygen meters.…”

Section: Introductionmentioning

confidence: 99%

Do Ultrafine Bubbles Work as Oxygen Carriers?

et al. 2023

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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.

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“…In the past few years, NBs have become one of the main topic of research to improve the treatment efficiency in the environmental science and engineering disciplines. The ability of NBs in water purification is usually interpreted and attributed to the production of free radicals or the effective increase in the gas mass transfer 3–5 and the DO level in the applied interfacial microenvironment; 6,7 however, their underlying mechanisms have not been fully understood to date.…”

Section: Introductionmentioning

confidence: 99%