POWDER TECHNOLOGY
·
2024
·
IF 4.5
Xinyu Liu,Han Guo,Shihao Ding,Qinglin Yin,Yaowen Xing,Xiahui Gui
Studies have reported that bubble coalescence causes particle–bubble detachment in the flotation pulp and foam phases. Most coalescence experiments have been conducted using bubble pairs with the same diameter; however, this is not the case in real flotation. In this study, particle–bubble detachment behavior during the coalescence of two bubbles with different sizes was investigated using a high–speed camera, and the variation of the coalescing bubble area was fitted to a damped oscillatory equation and analyzed. To explore the intrinsic detachment mechanism of the bubble size effect, the flow field variation in the bubble periphery was simulated using COMSOL 6.1. Results show that the particle–bubble detachment probability decreased with increasing bubble size difference. The released energy is greatest when the two equal bubbles coalesced, thus leading to the strongest oscillation and highest detachment probability. The simulation results show that turbulent kinetic energy affects particle-bubble stability and is an important reason for inducing particle-bubble detachment. Notably, particle–bubble detachment did not occur at the maximum turbulent energy, because there was a delay due to the time required for the sliding contraction of the three–phase contact line. The research finding provides new insights into the mechanism of particle–bubble detachment.
研究领域:
矿物加工工程
·
流体力学
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2022
·
IF 5.518
Ming Li,Ming Xu,Lijuan Sun,Chunyun Zhu,Jincheng Liu,Qinshan Liu,Yaowen Xing,Xiahui Gui
The surface microbubbles (SMBs) induced by air nucleation on mineral surfaces exert a powerful influence over enhancing the adhesion of air bubbles or oil droplets on mineral surfaces in flotation . The contact angles and TPLs were characterized by captive-bubble/oil droplet on the graphite surfaces. They were combined with dynamic bubble/oil droplet-graphite surface attachment and detachment visualization and force measurements using a microbalance system equipped with a camera to demonstrate the role of SMBs in bubble/oil droplet-graphite surface adhesion. The results show that after depressurization, the dissolved air in water nucleates on both hydrophobic and oxidized graphite surfaces, resulting in SMBs formation, which can enhance the adhesion of bubbles/oil droplets with the different graphite surfaces. For bubble-solid adhesion, these enhancements are attributed to the bridging effect of the SMBs coalescing with the large bubble increasing three-phrase contact lines (TPLs) and with this the adhesion forces. For oil-solid interactions, SMBs induce the attachment and spreading of the oil droplet on the graphite surfaces, as the TPLs and spreading forces are increased. SMBs also result in a more stable oil droplet-graphite interface, as the adhesion forces are improved. Therefore, SMBs are efficient for improving graphite flotation by increasing the stability of the mineralized bubble and promoting the spreading and adhesion of dodecane oil. Hence, SMBs coupled with the modification of the surface hydrophobicity may be more beneficial for flotation separation.
研究领域:
矿物加工工程
·
界面科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Surfaces and Interfaces
·
2021
·
IF 4.837
Man-Yu Qian,Ji-Huan He
A critical hurdle in membrane fabrication is the threshold thickness, beyond which the artificial membrane becomes impossible. In contrast, biological membranes have a nanoscale thickness, enabling their excellent permeability and remarkably perfect selectivity . We address this challenge by designing a novel bubble spinning process that can produce nanoscale members instead of nanofibers from polymer bubbles. The process herein is to enlarge the bubble so that the thickness of the bubble wall is only a few tens of nanometers. The fragments of the broken bubbles are received on a mesh receptor, and an artificial membrane with nanoscale thickness is obtained. This process sheds a bright light on the biomimetic fabrication of nanoscale membranes. Moreover, although our work focuses on the mechanism, we anticipate that the bubble spinning can be used for large-scale fabrication of natural-inspired extremely thin membranes with good permeability and ideal selectivity, and other functions.
研究领域:
材料科学
·
生物仿生学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING RESEARCH & DESIGN
·
2022
·
IF 4.119
Sijia Zhao,Ajuan Song,Yijun Cao,Siyuan Yang,Chao Li
The diameter of bubbles generated from submerged orifices is closely related to the air pressure, which consists of static and dynamic pressures. It has been proven that switching the air supply from a steady to oscillatory flow can improve the dynamic pressure and thus lead to smaller bubbles. To complement the control strategy for bubble size optimization, this study proposes an approach to enhance static pressure by introducing a Y-junction shunting configuration under an oscillatory air supply. A model of gas pressure as a function of the shunting ratio was developed and validated experimentally. A positive correlation was observed between the shunting ratio and static pressure. The bubble size first decreased and then increased as the shunting ratio increased from 0 to 3.0. The smallest bubbles were obtained at a shunting ratio of 1.5 with a diameter reduction of 26% compared with no shunting. By segregating the bubble formation process, the bubble diameter at detachment continuously decreases over the shunting ratio. However, the number of coalesced bubbles first decreased and then increased, and the underlying mechanism is discussed. The findings indicated that the shunting air supply could facilitate bubble size optimization when the shunting ratio was appropriately controlled.
研究领域:
流体力学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
WATER RESEARCH
·
2024
·
IF 11.4
Xiemin Liu,Jin Jin,Yu Gao,Zheng Zhou,Feng Zhang,Jiao Geng
Efforts have been made to enhance ozone utilization efficiency and reduce energy costs in ozone-aerated wastewater treatment. Microbubbles, characterized by their large interfacial area and efficient gas-liquid mass transfer, are extensively used to boost ozone utilization. However, generating microbubbles demands significant energy, and their actual efficiency requires careful evaluation due to the absence of universal strategies for designing microbubbles with optimal performance. This study established an integrated mathematical model for ozone oxidation in wastewater treatment, based on comprehensive ozone reaction kinetics, microbubble mass transfer control theory, and mass conservation equations for gas-liquid phase components. Simulation results showed a pollutant removal rate with a prediction error of less than 20 %, confirming the model's reliability. Further analysis revealed that although the initial mass transfer rate of 0.5 mm bubbles is lower than that of 0.1 mm bubbles, the total mass transfer quantity is reduced by only 8.7 %. This suggests that an optimal bubble diameter can balance mass transfer efficiency and energy consumption. Based on this finding, we integrated ozone production and bubble generation energy consumption to develop a regulation mechanism for optimizing bubble diameter, minimizing total energy consumption while meeting target removal rates. Results indicate that the optimal bubble diameter is closely related to water depth: as depth increases, the optimal bubble diameter also increases. At a depth of 2.1 meters, the optimized bubble diameter reduces energy consumption by 33.5 % and 16.2 % compared to millimeter-sized and 100-micron bubbles, respectively. Sensitivity analysis shows that total energy consumption is more sensitive to changes in specific ozone energy consumption, while variations in bubble generation energy remain relatively stable. These results underscore the feasibility of using the proposed model to guide energy-efficient bubble size selection.
研究领域:
环境科学
·
废水处理工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER TESTING
·
2020
·
IF 3.275
Lei Xu,Zhengliang Huang,Yao Yang,Binbo Jiang,Jingyuan Sun,Jingdai Wang,Yongrong Yang
High density polyethylene/n-Hexane system was adopted to investigate the bubbles nucleation and collapse in polymer melt with a visualization apparatus at different temperatures. The results showed that the initial bubble number, initial total bubble volume and the mean bubble diameter all increased with the temperature increasing, and the bubble diameter distribution changed from single peak distribution to bimodal distribution. Moreover, the effect of temperature on the maximum bubble diameter was mainly reflected in the change of the pressure in bubbles due to the change of the volatile content in the polyethylene melt. For bubble collapse, the collapse time became longer but the bubble collapse rate became faster with the temperature increasing, and a fitting model was established in which the collapse coefficient n was used to describe the collapse rate. Through dimension analysis, the correlation between the collapse coefficient n and the melt surface tension σ , zero-shear melt viscosity η 0 , diffusion coefficient D , maximum bubble diameter d max , melt density ρ , initial bubble number density N ini were established and the variation of D with temperature could be predicted as an exponential correlation.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Nature Communications
·
2025
·Vol. 16
·期 1
·1-11
·
IF 15.7
Yang Sheng,Yuan Jing,Xie Pengpeng,Li Bo,Li Mengxuan,Zhou Daojin,Luo Liang,Sun Xiaoming
To adapt fluctuating renewable energy for water splitting is challenging, since the growth of electrochemically generated nanobubbles at early stage requires high supersaturation during the repeated start-stop cycles, which can accelerate the deactivation of electrodes and cause extra energy consumption. Herein, we propose a “bubble seeding” strategy by introducing nanobubbles (NBs, ~200 nm in diameter) into electrolyte to promote the generation of macroscopic bubbles. The precursive nanobubbles can act as the beforehand nuclei with a certain supersaturation, lower the supersaturation barrier for further growth, and result in reduced overpotential as high as 130 mV for oxygen evolution reaction. The enhancement depends on nanobubble coverage and size, with higher coverage and larger sizes favoring macrobubble growth. The nanobubbles with inert gas species (e.g. N 2 for oxygen evolution reaction) can also work as the seeds, while the interfering or consumable gas species (e.g. O 2 for hydrogen evolution reaction) would hinder the generation of macroscopic bubbles and enlarge the overpotential. The water splitting device working at presence of nanobubbles exhibits stable operation voltage during repeated start-stop cycles in contrast to traditional electrolyte without NBs, indicating great potential of such traceless nanobubble additive strategy for stabilizing gas evolution applications.
研究领域:
电化学
·
能量转换
·
纳米技术
·
可再生能源系统
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Nano
·
2025
·
IF 16
Yunli Zhou,Jiaxin Feng,Jincan Pei,Canjun Liu,Jie Zhang,Zhangquan Peng
Bubble engineering enhances mass transfer in electrochemical gas-evolution devices by accelerating bubble detachment. Understanding dynamics from single-bubble growth to microscale bubble–bubble interactions is fundamental to bubble engineering but remains challenging. Herein, by integrating ultramicroelectrode electrochemistry with high-speed dark-field microscopy, we correlate electrochemical responses to bubble dynamics with synchronized optical signals, revealing dynamics beyond the single-bubble regime at millisecond temporal resolution and microscale spatial resolution. At the single-bubble level, position-dependent growth dynamics (edge vs center) of O2 bubbles generated during water electrolysis are characterized. An electrochemical method quantifies contact angles using residual current ratios and bubble diameters, revealing superior aerophobicity (θ ≈ 170°) of electrogenerated Ni(OH)2 surfaces. Crucially, beyond the single-bubble regime, we decipher electrode–bubble interactions and bubble–bubble interactions by prepositioning an O2 bubble adjacent to the electrode. Electrode–bubble interactions reveal electrochemically driven growth of a neighboring bubble and ∼30% enhancement of local mass transfer. Bubble–bubble interactions demonstrate coalescence-induced recovery of bubble-blocked current within ∼4 ms via accelerated detachment. These results highlight interactions transcending the single-bubble regime, specifically pairwise bubble interactions, and establish a mechanistic framework of counteract-bubbles-with-bubbles strategy for macroscopic bubble engineering. This strategy is expected to promote the structural design of practical gas-evolution devices with minimized mass transfer resistance.
研究领域:
电化学
·
微纳流体力学
·
界面科学
·
能源材料
·
反应工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF POWER SOURCES
·
2021
·
IF 9.127
Yuan Zhou,Yang Yang,Xun Zhu,Ding-ding Ye,Rong Chen,Qiang Liao
The power generation property of direct liquid fuel cells at high current densities is plagued by gas bubbles generation. Herein, we propose a bubble-trap layer to help mitigate the problem and improve the power generation stability performance. A novel chip-based liquid fuel cell with the bubble-trap layer is fabricated as a facile visualization and fast test platform, validating that most of CO 2 bubble releases from the bubble-trap layer in situ rather than at the microchannel outlet. The dynamic behaviors of gas bubbles are visualized and their impact on the power generation performance is discussed. It suggests the fuel cell equipped with the bubble-trap layer has superior power generation stability, power density (29 mW cm −2 ) and current density (163 mA cm −2 ), which are 10% and 27% higher than that without the bubble-trap layer. And a maximum power density of 35 mW cm −2 is achieved. The bubble growth and gas emission mechanisms are analyzed according to the mechanical model, providing a guidance for the channel design and operation condition determination of cells. These results demonstrate the viability of applying the bubble-trap layer for stabilizing power generation and cast new light on the structure design of direct liquid fuel cells.
研究领域:
能源科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
LANGMUIR
·
2022
·
IF 4.331
Dayong Li,Juan Gu,Yong Li,Ziqun Zhang,Yutong Ji
Trapped nanobubbles are observed nucleating at nanopits on a pitted substrate, while surface nanobubbles are usually formed on the smooth solid surface in water. In this work, trapped nanobubbles and surface nanobubbles were captured by a tapping-mode atomic force microscope (AFM) on a nanopitted substrate based on the temperature difference method. A single trapped nanobubble was manipulated to change into a surface nanobubble, then to change into the trapped nanobubble again. At the same time, surface nanobubbles can be moved to merge into a trapped nanobubble. Our results show that the scan load and the size of the scan area were the main factors that significantly affect the mobility of surface/trapped nanobubbles. The coalescence and mutual transformation of the two kinds of nanobubbles indicate that trapped nanobubbles and surface nanobubbles have the same chemical nature, which also provides vital experimental proof of the existence of nanobubbles in the course of contact line depinning. Our results are of great significance for understanding nanobubble stability and providing guidelines in some industrial applications.
研究领域:
物理学
·
材料科学
·
纳米技术
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Jiaxin Tang,Yanguang Shan,Youhua Jiang
Hypothesis : For an evaporating nanofluid droplet that contains a bubble inside, we suspect the bubble boundary remains pinned during evaporation whereas the droplet perimeter recedes. Thus, the dry-out patterns are mainly determined by the presence of the bubble and their morphology can be tuned by the size and location of the added bubble. Experiments : Bubbles with varying base diameters and lifetimes are added into evaporating droplets that contain nanoparticles with different types, sizes, concentrations, shapes, and wettability. The geometric dimensions of the dry-out patterns are measured. Findings : For a droplet containing a long-lifetime bubble, a complete ring-like deposit forms, and its diameter and thickness increases and decreases with the bubble base diameter, respectively. The ring completeness, i.e., the ratio of actual ring length to its imaginary perimeter, decreases with the decrease in bubble lifetime. The pinning of droplet receding contact line by particles near the bubble perimeter has been found to be the key factor leading to ring-like deposits. This study introduces a strategy of producing ring-like deposit and allows a control of the ring morphology in a simple, cheap, and impurity-free fashion, which is applicable to various applications associated with evaporative self-assembly.
研究领域:
材料科学
·
表面化学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Small
·
2020
·Vol. 16
·期 29
·2001548
·
IF 11.459
Xin Yan,Jinliang Xu,Zhijun Meng,Jian Xie,Hao Wang
Radiation pressure refers to the momentum transfer of photons during light “particles” impacting a surface. The force is too small to drive microengines. Different from the classical radiation pressure, the indirect radiation pressure ( F m ) is introduced, coming from the momentum change of light-induced bubble expansion. F m is shown to obey F m ∼ ( I · r b ) 2 , behaving faster growth of indirect radiation pressure versus light intensity I and bubble radius r b . An effective bubble size range is identified for F m to suppress other forces for bubble in liquid. The top laser irradiation on nanofluid is used in this experiment. A well-defined bubble pulsating flow, being a new principle of bubble piston engine, is demonstrated. During pulse on (≈ns scale), F m exceeding other forces generates an extremely large acceleration, which is three to four orders larger than the gravity acceleration, propelling the bubble traveling downward. During pulse off, the bubble is floating upward due to the nonexistence of F m . In such a way, the piston engine sustains the oscillating ranges of 38–347 µm for bubble diameters and 2.7–457.9 µm for traveling distances of piston. This work is useful to manipulate bubble dynamics in solar energy systems, and can find various applications in optofluidics.
研究领域:
光学
·
流体力学
·
微纳米技术
·
光流体学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）