A review of recent theoretical and computational studies on pinned surface nanobubbles

Liu, Yawei; Zhang, Xuehua

doi:10.1088/1674-1056/27/1/014401

Cited by 20 publications

(13 citation statements)

References 95 publications

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“…Combining these observations with the zeta potential results, it can be concluded that the nanobubbles and sodium oleate molecules are found to interact in solution, forming a hydrophobic group of sodium oleate molecules directed into the interior of the nanobubbles and a hydrophilic group exposed to the solution with a negatively charged nanobubble inclusion. As the hydrophilic group (carboxyl group) in the nanobubble inclusion interacts strongly with the surface of the mica, including electrostatic attraction, hydrogen bonding, and chemical bond forces − of the carboxyl and mica surface atoms, the entire nanobubble inclusion is adsorbed on the mica surface. The adsorption morphology of the sodium oleate and nanobubble solution on the mica surface at higher concentration is shown in Figure f.…”

Section: Resultsmentioning

confidence: 99%

Effect of Sodium Oleate on the Adsorption Morphology and Mechanism of Nanobubbles on the Mica Surface

et al. 2019

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Nanobubbles promote the flotation of fine-grained minerals. In the associated mechanism, the aggregation of fine particles is first promoted, which increases the probability of collision between particles and bubbles. However, the interaction between nanobubbles and mineral particles is often neglected, especially when the surface properties of the nanobubbles are modified by flotation collectors. In this study, the interaction mechanism between nanobubbles and the mica surface is investigated by nanoparticle tracking analysis, zeta potential measurement, and atomic force microscopy. The results reveal that the hydrophobic group of sodium oleate points toward the inside of the nanobubble and the hydrophilic group faces outward after the interaction of sodium oleate molecules and nanobubbles. A surfactant micelle with nanobubbles as the core is formed, thus considerably reducing the concentration of sodium oleate to form micelles. The adsorption of the modified nanobubbles on the mineral surface is carried out by the specific adsorption of the exposed hydrophilic group and the mineral surface. This adsorption method is superior to the hydrophobic interaction between the nanobubbles and the hydrophobic mineral surface. Further, the nanobubbles are highly selective for the activation sites on the mineral surface in the adsorption mode. This study will help understand the interaction between nanobubbles and collectors to further apply nanobubbles to treat fine-grained mineral particles.

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Section: Resultsmentioning

confidence: 99%

Effect of Sodium Oleate on the Adsorption Morphology and Mechanism of Nanobubbles on the Mica Surface

et al. 2019

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“…11. [179][180][181] If the internal pressure is not in balance with the degree of gas saturation in the surrounding liquid, the bubble gas should dissolve into the liquid, making the bubble smaller down to complete dissolution. The internal pressure of nanobubbles is, however, anomalously high, since an unrealistic supersaturation degree of the liquid would be required to ensure their existence.…”

Section: Bubble Mechanism: the Existential Crisis Of Nanobubblesmentioning

confidence: 99%

Plasma physics of liquids—A focused review

Vanraes

Bogaerts

2018

Applied Physics Reviews

181

118

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The interaction of plasma with liquids has led to various established industrial implementations as well as promising applications, including high-voltage switching, chemical analysis, nanomaterial synthesis, and plasma medicine. Along with these numerous accomplishments, the physics of plasma in liquid or in contact with a liquid surface has emerged as a bipartite research field, for which we introduce here the term "plasma physics of liquids." Despite the intensive research investments during the recent decennia, this field is plagued by some controversies and gaps in knowledge, which might restrict further progress. The main difficulties in understanding revolve around the basic mechanisms of plasma initiation in the liquid phase and the electrical interactions at a plasma-liquid interface, which require an interdisciplinary approach. This review aims to provide the wide applied physics community with a general overview of the field, as well as the opportunities for interdisciplinary research on topics, such as nanobubbles and the floating water bridge, and involving the research domains of amorphous semiconductors, solid state physics, thermodynamics, material science, analytical chemistry, electrochemistry, and molecular dynamics simulations. In addition, we provoke awareness of experts in the field on yet underappreciated question marks. Accordingly, a strategy for future experimental and simulation work is proposed.

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“…Molecular simulations have the spatial resolution to address these questions. However, while several computational studies have been carried out to shed light on the unexpected stability and nucleation of nanobubbles, − the nucleation and stationary states of electrochemically generated nanobubbles have never been studied by molecular simulations. In this work, we investigate the nucleation and stationary states of electrochemically generated nanobubbles, using molecular dynamics simulations with an algorithm that mimics the electro-generation of gas at the electrode.…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of Nucleation and Stationary States of Electrochemically Generated Nanobubbles

et al. 2019

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Gas evolving reactions are ubiquitous in the operation of electrochemical devices. Recent studies of individual gas bubbles on nanoelectrodes have resulted in unprecedented control and insights on their formation. The experiments, however, lack the spatial resolution to elucidate the molecular pathway of nucleation of nanobubbles and their stationary size and shape. Here we use molecular simulations with an algorithm that mimics the electrochemical formation of gas, to investigate the mechanisms of nucleation of gas bubbles on nanoelectrodes, and characterize their stationary states. The simulations reproduce the experimental currents in the induction and stationary stages, and indicate that surface nanobubbles nucleate through a classical mechanism. We identify three distinct regimes for bubble nucleation, depending on the binding free energy per area of bubble to the electrode, Δγ bind . If Δγ bind is negative, the nucleation is heterogeneous and the nanobubble remains bound to the electrode, resulting in a low-current stationary state. For very negative Δγ, the bubble fully wets the electrode, forming a one-layer-thick micropancake that nucleates without supersaturation. On the other hand, when Δγ bind > 0 the nanobubble nucleates homogeneously close to the electrode, but never attaches to it. We conclude that all surface nanobubbles must nucleate heterogeneously. The simulations reveal that the size and contact angle of stationary nanobubbles increase with the reaction driving force, although their residual current is invariant. The myriad of driven nonequilibrium stationary states with the same rate of production of gas, but distinct bubble properties, suggests that these dissipative systems have attractors that control the stationary current.

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A review of recent theoretical and computational studies on pinned surface nanobubbles

Cited by 20 publications

References 95 publications

Effect of Sodium Oleate on the Adsorption Morphology and Mechanism of Nanobubbles on the Mica Surface

Effect of Sodium Oleate on the Adsorption Morphology and Mechanism of Nanobubbles on the Mica Surface

Plasma physics of liquids—A focused review

Mechanisms of Nucleation and Stationary States of Electrochemically Generated Nanobubbles

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