Effect of aging time, airflow rate, and nonionic surfactants on the surface tension of bulk nanobubbles water

Bu, Xiangning; Zhou, Shaoqi; Tian, Xiaoling; Ni, Chao; Nazari, Sabereh; Alheshibri, Muidh

doi:10.1016/j.molliq.2022.119274

Cited by 28 publications

(21 citation statements)

References 42 publications

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“…They also reported the decrease in surface tension of an aqueous anionic surfactant solution containing BNBs. Bu et al found the decrease in surface tension of NB dispersion at a relatively low number concentration of BNBs. Zhou et al suggested the need to study the influence of dissolved air quantity in the water sample on the surface tension of NB dispersion on the basis of consistency between dissolved oxygen (DO) content and the number of bulk microbubbles.…”

Section: Introductionmentioning

confidence: 99%

Decrease in the Surface Tension of Nanobubble Dispersion in Water: Results of Surface Excess of Bulk Nanobubbles at Interfaces

2023

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The effect of nanobubbles (NBs) on the surface tension of liquid was investigated by three methods of different measuring principles, pendant drop (PD), Wilhelmy, and du Nouÿ methods, over a wide range of number concentration of bulk NBs (BNBs). In all of the three methods, the surface tension decreased in proportion to the number concentration of BNBs and the proportional constant was different among the three methods. Such behavior was inferred to be caused by the surface excess of BNBs at the gas−liquid or solid−liquid interface. In the PD method, the hydrophobic interaction between BNBs and air around a drop seems to cause the surface excess of BNBs along the surface of water drops. It brings about a subtle change in its profile, resulting in the decrease in surface tension, which takes a time of hundreds of seconds. Meanwhile, in the Wilhelmy and du Nouÿ methods, electrostatic attractive force between BNBs and a plate or ring is a likely cause of surface excess at the solid−liquid interface, resulting in the instantaneous decrease in surface tension. This study also provides a practical methodology of comparison for surface tension of NB dispersion: surface tension shall be compared among different samples with the same measurement method. Especially in the PD method, retention time of droplets before measurement shall be the same among samples.

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Section: Introductionmentioning

confidence: 99%

Decrease in the Surface Tension of Nanobubble Dispersion in Water: Results of Surface Excess of Bulk Nanobubbles at Interfaces

2023

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“…However, the inhibition effect of electrolytes on A-NB coalescence was ascribed to the changes in the Gibbs elasticity of solutions, the Marangoni effect, and the reduction of attraction and hydrophobicity between A-NBs . In addition, electrolytes compressed the thickness of the A-NB double layer and reduced the surface charge density, energy barrier, and size of A-NBs. , It was suggested that the mechanism for the inhibition effect of inorganic electrolytes on A-NB coalescence was similar to that of foaming agents, which involved surface tension gradient and hydrogen bonds. − Based on the above reports and the analysis results in Figure , we believe that the reduction of A-NB size in electrolyte solutions was mainly caused by the compression of the electrical double layer, but the contribution of the surface tension change was small.…”

Section: Resultsmentioning

confidence: 99%

Physicochemical Characteristics and the Scale Inhibition Effect of Air Nanobubbles (A-NBs) in a Circulating Cooling Water System

et al. 2023

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Air nanobubbles (A-NBs) in a circulating cooling water system have not been investigated, although their role is significant. In this paper, the influences of the contents of main salts and other parameters on the physicochemical characteristics and scale inhibition performance of A-NBs in circulating cooling water were investigated and the scale inhibition mechanism of A-NBs in a simulated circulating cooling water system was explored. A-NBs realized a higher scale inhibition rate of 90%, which was higher than that of 1-hydroxyethane-1,1-diphosphonic acid (40%), and A-NBs stably existed for more than 5 days in the complex water environment. Four interface functions were proposed to interpret the scale inhibition effect of A-NBs in circulating cooling water as follows. First, the negatively charged surface of A-NBs adsorbed cations (Ca 2+ ) reduced the concentration of scaling ions. Second, the negatively charged surface of A-NBs could also adsorb microcrystals, and their crystal-like seed action was conducive to the formation of large-size crystals, broke the rules of crystal growth, and reduced the adhesion of scales to the pipe wall. Third, A-NBs could also form a bubble layer after they were adsorbed on the inner surface of pipes, thereby preventing the deposition of scales on the surface. Fourth, A-NB burst caused local turbulence, increased the shear force onto the pipe surface, and reduced the scales adhering to the pipe surface. The interface effect of A-NBs in metal pipes is important in many industrial applications. This study laid the basis for the development of a new green A-NB scale-inhibiting technology.

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“…There are various theoretical models for the stability of UFBs [ 41 , 54 , 55 ]. In the author’s opinion, the most promising model is the dynamic equilibrium model because there is experimental evidence of images, and the reduction in surface tension of UFB water is solely explained by the model [ 49 , 55 , 56 , 57 , 58 , 59 , 60 , 61 ]. The dynamic equilibrium model is as follows [ 56 ]: A gas bubble is assumed to be partly covered with hydrophobic impurities such as oils, carbon particles, etc., as shown in Figure 1 [ 56 ].…”

Section: Bulk Nanobubbles (Ultrafine Bubbles)mentioning

confidence: 99%

“…This is a piece of evidence for the dynamic equilibrium model. Furthermore, as more than 50% of the bubble surface is covered with hydrophobic materials according to the dynamic equilibrium model, UFBs can be stable at the liquid surface when the covered part of the bubble surface is directed toward the gas phase [ 58 , 60 ]. On the other hand, uncovered bubbles burst at the liquid surface and immediately disappear.…”

Section: Bulk Nanobubbles (Ultrafine Bubbles)mentioning

confidence: 99%

Critical Roles of Impurities and Imperfections in Various Phases of Materials

Yasui

2023

Materials

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In many materials, impurities and imperfections play a critical role on the physical and chemical properties. In the present review, some examples of such materials are discussed. A bulk nanobubble (an ultrafine bubble) is stabilized against dissolution by hydrophobic impurities attached to the bubble surface. An acoustic cavitation threshold in various liquids decreases significantly by the presence of impurities such as solid particles, etc. The strength of brittle ceramics is determined by the size and number of pre-existing microcracks (imperfections) in the specimen. The size effect of a BaTiO3 nanocrystal is influenced by the amount and species of adsorbates (impurities) on its surface as adsorbate-induced charge-screening changes the free energy. The dielectric constant of an assembly of BaTiO3 nanocubes is influenced by a small tilt angle (imperfection) between two attached nanocubes, which induces strain inside a nanocube, and is also influenced by the spatial strain–relaxation due to defects and dislocations (imperfections), resulting in flexoelectric polarization.

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Effect of aging time, airflow rate, and nonionic surfactants on the surface tension of bulk nanobubbles water

Cited by 28 publications

References 42 publications

Decrease in the Surface Tension of Nanobubble Dispersion in Water: Results of Surface Excess of Bulk Nanobubbles at Interfaces

Decrease in the Surface Tension of Nanobubble Dispersion in Water: Results of Surface Excess of Bulk Nanobubbles at Interfaces

Physicochemical Characteristics and the Scale Inhibition Effect of Air Nanobubbles (A-NBs) in a Circulating Cooling Water System

Critical Roles of Impurities and Imperfections in Various Phases of Materials

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