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Palliyalil AC, Mohan A, Dash S, Tomar G. Ion-Specific Bubble Coalescence Dynamics in Electrolyte Solutions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:1035-1045. [PMID: 38134361 DOI: 10.1021/acs.langmuir.3c03259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
Bubble coalescence time scale is important in applications such as froth flotation, food and pharmaceutical industries, and two-phase thermal management. The time scale of coalescence is sensitive to the dissolved ions. In this study, we investigate the evolution of a thin electrolyte film between a bubble and a hydrophilic substrate during coalescence. We present a thin-film equation-based numerical model that accounts for the dependence of the surface tension gradient and electric double layer (EDL) on the concentration of ions at the air-liquid interface. The influence of Marangoni stresses and the EDL on the hydrodynamics of drainage determines the coalescence time scale. We show that the electrolytes, such as NaCl, Na2SO4, and NaI retard coalescence, in contrast to HCl and HNO3 that have little effect on the coalescence time scale. We also show that the drainage of the electrolyte films with higher concentrations is retarded due to increased Marangoni stresses at the air-water interface. The slow drainage triggers an early formation of the dimple in the thin film, thus trapping more fluid within, which further decreases the drainage rate. For a hydrophilic substrate, EDL along with van der Waals for a given concentration governs the final dynamics of thin films, eventually resulting in a stable thin layer of the electrolyte between the bubble and the substrate. The stabilizing thickness reduces by an order of magnitude as the NaCl concentration increases from 0.01 to 10 mM. For Na2SO4 solution, the film is stabilized at a smaller thickness due to higher valency cations resulting in higher screening of the EDL repulsion.
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Affiliation(s)
| | - Ananthan Mohan
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Susmita Dash
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Gaurav Tomar
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore 560012, India
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Xie L, Wang J, Lu Q, Hu W, Yang D, Qiao C, Peng X, Peng Q, Wang T, Sun W, Liu Q, Zhang H, Zeng H. Surface interaction mechanisms in mineral flotation: Fundamentals, measurements, and perspectives. Adv Colloid Interface Sci 2021; 295:102491. [PMID: 34332278 DOI: 10.1016/j.cis.2021.102491] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 07/16/2021] [Accepted: 07/18/2021] [Indexed: 12/23/2022]
Abstract
As non-renewable natural resources, minerals are essential in a broad range of biological and technological applications. The surface interactions of mineral particles with other objects (e.g., solids, bubbles, reagents) in aqueous suspensions play a critical role in mediating many interfacial phenomena involved in mineral flotation. In this work, we have reviewed the fundamentals of surface forces and quantitative surface property-force relationship of minerals, and the advances in the quantitative measurements of interaction forces of mineral-mineral, bubble-mineral and mineral-reagent using nanomechanical tools such as surface forces apparatus (SFA) and atomic force microscope (AFM). The quantitative correlation between surface properties of minerals at the solid/water interface and their surface interaction mechanisms with other objects in complex aqueous media at the nanoscale has been established. The existing challenges in mineral flotation such as characterization of anisotropic crystal plane or heterogeneous surface, low recovery of fine particle flotation, and in-situ electrochemical characterization of collectorless flotation as well as the future work to resolve the challenges based on the understanding and modulation of surface forces of minerals have also been discussed. This review provides useful insights into the fundamental understanding of the intermolecular and surface interaction mechanisms involved in mineral processing, with implications for precisely modulating related interfacial interactions towards the development of highly efficient industrial processes and chemical additives.
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Affiliation(s)
- Lei Xie
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Jingyi Wang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Qiuyi Lu
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Wenjihao Hu
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada; School of Metallurgy and Environment, Central South University, Changsha 410083, China
| | - Diling Yang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Chenyu Qiao
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Xuwen Peng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Qiongyao Peng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Tao Wang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Wei Sun
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China
| | - Qi Liu
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Hao Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
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Liu B, Manica R, Xu Z, Liu Q. The boundary condition at the air–liquid interface and its effect on film drainage between colliding bubbles. Curr Opin Colloid Interface Sci 2020. [DOI: 10.1016/j.cocis.2020.07.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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4
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Forces between a hard surface and an air–aqueous interface with and without films. Curr Opin Colloid Interface Sci 2020. [DOI: 10.1016/j.cocis.2019.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Villa S, Stocco A, Blanc C, Nobili M. Multistable interaction between a spherical Brownian particle and an air-water interface. SOFT MATTER 2020; 16:960-969. [PMID: 31845955 DOI: 10.1039/c9sm01472a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report the measurement of the interaction energy between a charged Brownian polystyrene particle and an air-water interface. The interaction potential is obtained from the Boltzmann equation by tracking particle interface distance with a specifically designed Dual-Wave Reflection Interference Microscopy (DW-RIM) setup. The particle has two equilibrium positions located at few hundreds of nanometers from the interface. The farthest position is well accounted by a DLVO model complemented by gravity. The closest one, not predicted by current models, more frequently appears in water solutions at relatively high ions concentrations, when electrostatic interaction is screened out. It is accompanied by a frozen rotational diffusion dynamics that suggests an interacting potential dependent on particle orientation and stresses the decisive role played by particle surface heterogeneities. Building up on both such experimental results, the important role of air nanobubbles pinned on the particle interface is discussed.
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Affiliation(s)
- Stefano Villa
- Laboratoire Charles Coulomb (L2C), University of Montpellier, CNRS, Montpellier, France.
| | - Antonio Stocco
- Institut Charles Sadron (ICS), University of Strasbourg, CNRS, Strasbourg, France
| | - Christophe Blanc
- Laboratoire Charles Coulomb (L2C), University of Montpellier, CNRS, Montpellier, France.
| | - Maurizio Nobili
- Laboratoire Charles Coulomb (L2C), University of Montpellier, CNRS, Montpellier, France.
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Carnie SL, Del Castillo L, Horn RG. Mobile Surface Charge Can Immobilize the Air/Water Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:16043-16052. [PMID: 31310140 DOI: 10.1021/acs.langmuir.9b01691] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Recent Surface Force Apparatus measurements on thin film drainage as a bubble approaches a surface are reinterpreted in terms of a new model for the air/water interface. In this model, surface charge at the interface can be convected and can diffuse along the surface as the film drains. This creates surface tension gradients, since surface tension includes a charge-dependent contribution from the double-layer free energy. Although this electrocapillary effect is relatively small, we show here that the gradients are large enough to create Marangoni effects that influence the hydrodynamic flow in real systems. The new model can account for observed changes in hydrodynamic boundary condition from mobile initially to immobile during early stages of film drainage, and back to partially mobile as drainage progresses. Experimental film profiles for a millimeter-size bubble in 1 mM KCl solution driven toward a mica surface at 27 μm/s are reasonably well described with this mobile surface charge model. At longer times, there are still features of the experimental data that remain to be explained, which suggests further modeling is warranted.
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Affiliation(s)
- Steven L Carnie
- School of Mathematics and Statistics , The University of Melbourne , Parkville 3010 , Australia
| | - Lorena Del Castillo
- Future Industries Institute , University of South Australia , Mawson Lakes 5095 , Australia
| | - Roger G Horn
- School of Chemistry , Monash University , Clayton 3168 , Australia
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Kékicheff P. The long-range attraction between hydrophobic macroscopic surfaces. Adv Colloid Interface Sci 2019; 270:191-215. [PMID: 31277036 DOI: 10.1016/j.cis.2019.06.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 10/26/2022]
Abstract
Direct measurements of the long-range strongly attractive force observed between macroscopic hydrophobic surfaces across aqueous solutions are reexamined in light of recent experiments and theoretical developments. The focus is on systems in the absence of submicroscopic bubbles (preexistent or induced) to avoid capillary bridging forces. Other possible interferences to the measurements are also eliminated. The force-distance profiles are obtained directly (no contributions from electrical double layer or hydrodynamics) between symmetric identical hydrophobic surfaces, overall charge-neutral, at the thermodynamic equilibrium and in a quenched state. Therefore in the well-defined geometry of crossed-cylinders, sphere-flat, or sphere-sphere, there is no additional interaction to be considered except the ever-present dispersion forces, negligible at large separations. For the three main categories of substrates rendered hydrophobic, namely surfaces obtained with surfactant monolayers physically adsorbed from solution to deposited ones, and substrates coated with a hydrophobizing agent bonded chemically onto the surface, the interaction energy scales as A exp (-2κD)/2κD at large separations, with measured decay lengths in accord with theoretical predictions, simply being half the Debye screening length, κ-1/2, at least in non vanishing electrolyte. Taken together with the prefactor A scaling as the ionic strength, the interaction energy is demonstrated to have an electrostatic origin in all the systems. Thanks to our recent SFAX coupling force measurements with x-ray solution scattering under controlled nano-confinement, the microstructuration of the adsorbed film emerges as an essential feature in the molecular mechanism for explaining the observed attraction of larger magnitude than dispersion forces. The adsorption of pairs of positive and negative ions on small islands along the interface, the fluctuation of the surface charge density around a zero mean-value with desorption into or adsorption from the electrolyte solution, the correlations in the local surface ion concentrations along the surfaces, the redistribution of counterions upon intersurface variation, all contribute and are tuned finely by the inhomogeneities and defects present in the hydrophobic layers. It appears that the magnitude of the interacting energy can be described by a single master curve encompassing all the systems.
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Liu B, Manica R, Liu Q, Klaseboer E, Xu Z, Xie G. Coalescence of Bubbles with Mobile Interfaces in Water. PHYSICAL REVIEW LETTERS 2019; 122:194501. [PMID: 31144923 DOI: 10.1103/physrevlett.122.194501] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 02/11/2019] [Indexed: 06/09/2023]
Abstract
The fluid flow inside a thin liquid film can be dramatically modified by the hydrodynamic boundary condition at the interfaces. Aqueous systems can be easily contaminated by trace amounts of impurities, rendering the air-liquid interface immobile, thereby significantly resisting the fluid flow. Using high speed interferometry, rapid thinning of the liquid film, on the order of the collision speed, was observed between two fast approaching air bubbles in water, indicating negligible resistance and a fully mobile boundary condition at the air-water interface. By adding trace amounts of surfactants that changed the interfacial tension by 10^{-4} N/m, a transition from mobile to immobile was observed. This provides a fundamental explanation why the bubble coalescence time can vary by over 3 orders of magnitude.
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Affiliation(s)
- Bo Liu
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton T6G 1H9, Canada
| | - Rogerio Manica
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton T6G 1H9, Canada
| | - Qingxia Liu
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton T6G 1H9, Canada
| | - Evert Klaseboer
- Institute of High Performance Computing, 1 Fusionopolis Way, Singapore 138632
| | - Zhenghe Xu
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton T6G 1H9, Canada and Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Guangyuan Xie
- Department of Chemical Engineering, China University of Mining and Technology, Xuzhou 221116, China
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Liu B, Manica R, Zhang X, Bussonnière A, Xu Z, Xie G, Liu Q. Dynamic Interaction between a Millimeter-Sized Bubble and Surface Microbubbles in Water. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:11667-11675. [PMID: 30183304 DOI: 10.1021/acs.langmuir.8b01202] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The coalescence between microbubbles and millimeter-sized bubbles is an elementary process in various industrial applications such as froth flotation and wastewater treatment. Fundamental understanding of the coalescence behavior between two colliding bubbles requires knowledge of water drainage from the thin liquid film between the deformable air-water surfaces, a simple phenomenon with high complexity in physics because of the interplay of surface forces, hydrodynamic drainage, and surface rheology. In this work, we performed simultaneous measurements of the interaction force and spatial thin-film thickness during the collision between a millimeter-sized bubble (radius 1.2 mm) and surface microbubbles (radii between 30 and 700 μm) using our recently developed dynamic force apparatus. The interaction force during the collision agrees well with the prediction from the Stokes-Reynolds-Young-Laplace model with the tangentially immobile boundary condition at the air-liquid interface. However, the measured coalescence times for different bubble sizes are shorter than the model predictions, possibly caused by a rapid drainage behavior along with the loss of symmetry of the thin liquid film. In dozens of experimental runs, the bubbles coalesced at a critical film thickness of 25 ± 15 nm, which agrees reasonably well with the predicted rupture thickness using attractive van der Waals interaction force. These results suggest that the nonsymmetric drainage process, rather than the rupture thickness, contributes to the scattering of the experimental coalescence time between two fast-colliding air bubbles. Furthermore, our results suggest that smaller surface bubbles (30-100 μm) are more effective for the attachment onto a large bubble as the coalescence time decreases considerably when the microbubbles are smaller than 100 μm.
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Affiliation(s)
- Bo Liu
- Department of Chemical and Materials Engineering , University of Alberta , Edmonton T6G 1H9 , Canada
| | - Rogerio Manica
- Department of Chemical and Materials Engineering , University of Alberta , Edmonton T6G 1H9 , Canada
| | - Xurui Zhang
- Department of Chemical and Materials Engineering , University of Alberta , Edmonton T6G 1H9 , Canada
| | - Adrien Bussonnière
- Department of Chemical and Materials Engineering , University of Alberta , Edmonton T6G 1H9 , Canada
| | - Zhenghe Xu
- Department of Chemical and Materials Engineering , University of Alberta , Edmonton T6G 1H9 , Canada
| | - Guangyuan Xie
- Department of Chemical Engineering , China University of Mining and Technology , Xuzhou 221116 , China
| | - Qingxia Liu
- Department of Chemical and Materials Engineering , University of Alberta , Edmonton T6G 1H9 , Canada
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Ionic strength and ion-specific effects on the cloud point and the gel swelling of thermo-sensitive polymers in water. Colloid Polym Sci 2018. [DOI: 10.1007/s00396-018-4363-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Xing Y, Gui X, Pan L, Pinchasik BE, Cao Y, Liu J, Kappl M, Butt HJ. Recent experimental advances for understanding bubble-particle attachment in flotation. Adv Colloid Interface Sci 2017; 246:105-132. [PMID: 28619381 DOI: 10.1016/j.cis.2017.05.019] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 05/29/2017] [Accepted: 05/30/2017] [Indexed: 11/27/2022]
Abstract
Bubble-particle interaction is of great theoretical and practical importance in flotation. Significant progress has been achieved over the past years and the process of bubble-particle collision is reasonably well understood. This, however, is not the case for bubble-particle attachment leading to three-phase contact line formation due to the difficulty in both theoretical analysis and experimental verification. For attachment, surface forces play a major role. They control the thinning and rupture of the liquid film between the bubble and the particle. The coupling between force, bubble deformation and film drainage is critical to understand the underlying mechanism responsible for bubble-particle attachment. In this review we first discuss the advances in macroscopic experimental methods for characterizing bubble-particle attachment such as induction timer and high speed visualization. Then we focus on advances in measuring the force and drainage of thin liquid films between an air bubble and a solid surface at a nanometer scale. Advances, limits, challenges, and future research opportunities are discussed. By combining atomic force microscopy and reflection interference contrast microscopy, the force, bubble deformation, and liquid film drainage can be measured simultaneously. The simultaneous measurement of the interaction force and the spatiotemporal evolution of the confined liquid film hold great promise to shed new light on flotation.
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Affiliation(s)
- Yaowen Xing
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China; Chinese National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China; Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Xiahui Gui
- Chinese National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China; Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
| | - Lei Pan
- Department of Chemical Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton 49931, USA
| | - Bat-El Pinchasik
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Yijun Cao
- Chinese National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China
| | - Jiongtian Liu
- Chinese National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China
| | - Michael Kappl
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
| | - Hans-Jürgen Butt
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
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Effects of NaCl, NaOH, and HCl concentration on the cloud point of poly(vinyl methyl ether) in water—electrostatic interactions are inevitably involved in the hydrophobic interaction. Colloid Polym Sci 2017. [DOI: 10.1007/s00396-017-4130-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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