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Yang ZY, Yang SZ, Sun GZ, Wang WD, Fei D, Mu BZ, Gang HZ. High efficiency of biosurfactants in stabilizing oil micro-droplets within the aging time scale of milliseconds: a microfluidic study. SOFT MATTER 2024; 20:6635-6647. [PMID: 39109438 DOI: 10.1039/d4sm00630e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/23/2024]
Abstract
Rapid adsorption of surfactants onto a freshly formed interface is vital for emulsification because emulsification is a competitive process occurring between the very short time span of interface formation and surfactant mass transport. The biosurfactant surfactin has been previously reported to reach adsorption equilibrium at the hydrophobic/hydrophilic interface within hundreds of milliseconds and rapidly reduce the interfacial tension compared to chemically synthesized surfactants. According to a prior study, surfactin is expected to exhibit good performance in stabilizing micro-droplets of oil within the aging time scale of milliseconds. Herein, the stabilities of micro-droplets of n-hexadecane in the presence of a biosurfactant, surfactin (C15-SFT), and a chemically synthesized surfactant, sodium cetyl benzene sulfonate (8-SCBS), were investigated using a microfluidic method. The coalescence frequency of micro-droplets, the evolution of micro-droplet size, and the coalescence time of micro-droplets were evaluated. The results indicated that C15-SFT exhibited superiority over 8-SCBS in stabilizing the micro-droplets of n-hexadecane. Biosurfactant C15-SFT effectively reduced the fusion probability between oil droplets and elongated the coalescence time compared to 8-SCBS, and these phenomena were obvious at a shorter aging time (150 ms) and lower surfactant concentration (0.1 × critical micelle concentration). The stabilities of micro-droplets increased with aging time and the bulk concentration of surfactants. Stable micro-droplets of n-hexadecane were formed in 1 × 10-4 mol L-1 C15-SFT solution at 600 ms aging time, and the bulk concentration was 1 × 10-3 mol L-1 in the case of 8-SCBS. The micro-droplets rarely coalesced in the presence of 1 × 10-4 mol L-1 C15-SFT after 600 ms aging time, but the micro-droplets in 1 × 10-4 mol L-1 8-SCBS coalesced frequently in the midstream and downstream of the coalescence chamber, and big droplets were dominant in the emulsion. The coalescence time of micro-droplets stabilized by C15-SFT was obviously longer than that of those stabilized by 8-SCBS under the same condition, indicating that the interfacial film formed by C15-SFT has much strength to resist coalescence during collisions. This work is helpful for understanding the activity of lipopeptides in the very short early stage of the emulsification process, laying the foundation for biosurfactant research in the fields of enhanced oil recovery, bioremediation of contaminated water or soil, etc.
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Affiliation(s)
- Zhi-Yuan Yang
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering, East China University of Science and Technology, Meilong 130, 200237 Shanghai, P. R. China
| | - Shi-Zhong Yang
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering, East China University of Science and Technology, Meilong 130, 200237 Shanghai, P. R. China
- Engineering Research Center of Microbial Enhanced Oil Recovery, MOE, East China University of Science and Technology, Meilong 130, Shanghai, 200237, P. R. China
| | - Gang-Zheng Sun
- Shengli Oilfield Company, Sinopec, Dongying, 257000, P. R. China
- Research Institute of Petroleum Engineering and Technology, Shengli Oilfield Company, Sinopec, Dongying, 257000, P. R. China
| | - Wei-Dong Wang
- Shengli Oilfield Company, Sinopec, Dongying, 257000, P. R. China
| | - Dan Fei
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering, East China University of Science and Technology, Meilong 130, 200237 Shanghai, P. R. China
| | - Bo-Zhong Mu
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering, East China University of Science and Technology, Meilong 130, 200237 Shanghai, P. R. China
- Engineering Research Center of Microbial Enhanced Oil Recovery, MOE, East China University of Science and Technology, Meilong 130, Shanghai, 200237, P. R. China
| | - Hong-Ze Gang
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering, East China University of Science and Technology, Meilong 130, 200237 Shanghai, P. R. China
- Engineering Research Center of Microbial Enhanced Oil Recovery, MOE, East China University of Science and Technology, Meilong 130, Shanghai, 200237, P. R. China
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Arbabi S, Deuar P, Denys M, Bennacer R, Che Z, Theodorakis PE. Molecular dynamics simulation of the coalescence of surfactant-laden droplets. SOFT MATTER 2023; 19:8070-8080. [PMID: 37801284 DOI: 10.1039/d3sm01046e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
We investigate the coalescence of surfactant-laden water droplets by using several different surfactant types and a wide range of concentrations by means of a coarse-grained model obtained by the statistical associating fluid theory. Our results demonstrate in detail a universal mass transport mechanism of surfactant across many concentrations and several surfactant types during the process. Coalescence initiation is seen to occur via a single pinch due to aggregation of surface surfactant, and its remnants tend to become engulfed in part inside the forming bridge. Across the board we confirm the existence of an initial thermal regime with constant bridge width followed by a later inertial regime with bridge width scaling roughly as the square root of time, but see no evidence of an intermediate viscous regime. Coalescence becomes slower as surfactant concentration grows, and we see evidence of the appearance of a further slowdown of a different nature for several times the critical concentration. We anticipate that our results provide further insights in the mechanisms of coalescence of surfactant-laden droplets.
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Affiliation(s)
- Soheil Arbabi
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland.
| | - Piotr Deuar
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland.
| | - Mateusz Denys
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland.
| | - Rachid Bennacer
- Université Paris-Saclay, CentraleSupélec, ENS Paris-Saclay, CNRS, LMPS - Laboratoire de Mécanique Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - Zhizhao Che
- State Key Laboratory of Engines, Tianjin University, 300350 Tianjin, China
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Jylhä JP, Jokilaakso A. CFD-DEM models for matte droplet settling in a flash smelting settler. Heliyon 2023; 9:e21570. [PMID: 37954391 PMCID: PMC10638000 DOI: 10.1016/j.heliyon.2023.e21570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/02/2023] [Accepted: 10/24/2023] [Indexed: 11/14/2023] Open
Abstract
The flash smelting process is widely used in copper production. In the process, sulfidic feed and flux are oxidized. The heat released in the reactions melts the feed which forms a slag layer through which matte droplets must settle. Understanding the different phenomena affecting the settling is important to minimize losses. Due to the high temperature, simulation methods were employed to study settling. In this work, coupled CFD-DEM was used to study the effect of coalescence and reactions with in-house built submodels and scaled-down geometries. Colliding droplets often coalesce into larger droplets while reactions decrease their size and make them denser. These increase the settling velocity which is further enhanced by the formation of a channeling flow. Channels make the droplet cluster denser causing more collisions. This method enables the phenomena to be studied at the individual droplets' details, although simulating a full-scale process is beyond the available computational resources.
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Affiliation(s)
- Jani-Petteri Jylhä
- Aalto University, School of Chemical Engineering, Department of Chemical and Metallurgical Engineering, Kemistintie 1, Espoo, 02150, Finland
| | - Ari Jokilaakso
- Aalto University, School of Chemical Engineering, Department of Chemical and Metallurgical Engineering, Kemistintie 1, Espoo, 02150, Finland
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4
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Jayakumar J, Ballon A, Pallarès J, Vernet A, de Lamo-Castellví S, Güell C, Ferrando M. Lesser mealworm (A. diaperinus) protein as a replacement for dairy proteins in the production of O/W emulsions: Droplet coalescence studies using microfluidics under controlled conditions. Food Res Int 2023; 172:113100. [PMID: 37689864 DOI: 10.1016/j.foodres.2023.113100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/29/2023] [Accepted: 06/09/2023] [Indexed: 09/11/2023]
Abstract
Dairy proteins are commonly used to stabilize oil-in-water (O/W) emulsions, which can be replaced by other sustainable sources of proteins, such as insects. This study investigated the potential of lesser mealworm protein concentrate (LMPC) as a sustainable alternative to whey protein isolate (WPI) in stabilizing oil-in-water (O/W) emulsions using microfluidics. The frequency of coalescence (Fcoal) was calculated using images of emulsion droplets obtained near the inlet and outlet of the coalescence channel. The stability of O/W emulsions, produced using sunflower oil (SFO) or hexadecane and stabilized with varying concentrations of LMPC and WPI (0.02% to 0.0005% w/v), was compared under controlled conditions. The dispersed phase fraction (5.3%-14.3% v/v), protein adsorption time onto oil droplets (0.0398-0.158 s), and pH (pH = 3 and pH = 7) were also studied. Fcoal was greatest (0.42 s-1) when the protein concentration was lowest (0.0005%), the oil percentage was highest (14.3%), the adsorption period was shortest (0.0398 s), and the pH was 3. Droplet diameters did not vary significantly, with values between 55 and 118 μm, across protein concentrations or adsorption periods, but a rise in oil fraction resulted in a substantial increase in droplet diameters. Increases in protein content, adsorption duration, and oil percentage all resulted in increased stability (reduction of Fcoal). While LMPC and WPI showed similar results in microfluidic experiments and other test conditions, further research is needed to verify LMPC's efficacy as a replacement for WPI in food emulsification. Nonetheless, the findings suggest that LMPC has potential as a substitute for WPI in this application.
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Affiliation(s)
- Jitesh Jayakumar
- Departament d'Enginyeria Química, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Spain
| | - Aurélie Ballon
- Departament d'Enginyeria Química, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Spain
| | - Jordi Pallarès
- Departament d'Enginyeria Mecànica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Spain
| | - Anton Vernet
- Departament d'Enginyeria Mecànica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Spain
| | - Sílvia de Lamo-Castellví
- Departament d'Enginyeria Química, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Spain
| | - Carme Güell
- Departament d'Enginyeria Química, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Spain
| | - Montserrat Ferrando
- Departament d'Enginyeria Química, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Spain.
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A Microfluidic Approach to Investigate the Contact Force Needed for Successful Contact-Mediated Nucleation. COLLOIDS AND INTERFACES 2023. [DOI: 10.3390/colloids7010012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Emulsions with crystalline dispersed phase fractions are becoming increasingly important in the pharmaceutical, chemical, and life science industries. They can be produced by using two-stage melt emulsification processes. The completeness of the crystallization step is of particular importance as it influences the properties, quality, and shelf life of the products. Subcooled, liquid droplets in agitated vessels may contact an already crystallized particle, leading to so-called contact-mediated nucleation (CMN). Energetically, CMN is a more favorable mechanism than spontaneous nucleation. The CMN happens regularly because melt emulsions are stirred during production and storage. It is assumed that three main factors influence the efficiency of CNM, those being collision frequency, contact time, and contact force. Not all contacts lead to successful nucleation of the liquid droplet, therefore, we used microfluidic experiments with inline measurements of the differential pressure to investigate the minimum contact force needed for successful nucleation. Numerical simulations were performed to support the experimental data obtained. We were able to show that the minimum contact force needed for CMN increases with increasing surfactant concentration in the aqueous phase.
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ØYE G, SIMON S, RUSTAD T, PASO K. Trends in Food Emulsion Technology: Pickering, Nano and Double Emulsions. Curr Opin Food Sci 2023. [DOI: 10.1016/j.cofs.2023.101003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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7
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Schroën K, Deng B, Berton-Carabin C, Marze S, Corstens M, Hinderink E. Microfluidics-based observations to monitor dynamic processes occurring in food emulsions and foams. Curr Opin Food Sci 2023. [DOI: 10.1016/j.cofs.2023.100989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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8
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Ren X, Wang X, Jing B, Xiong Y, Duan M, Fang S. Preparation of acrylate-modified cationic flocculant by polymer reaction and its performance in treating oilfield-produced water. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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9
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Design of shear-based microfluidic channels for production and stability assessment of food emulsions. Curr Opin Food Sci 2022. [DOI: 10.1016/j.cofs.2022.100957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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10
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Deng B, Schroën K, de Ruiter J. Dynamics of bubble formation in spontaneous microfluidic devices: Controlling dynamic adsorption via liquid phase properties. J Colloid Interface Sci 2022; 622:218-227. [DOI: 10.1016/j.jcis.2022.04.115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/28/2022] [Accepted: 04/20/2022] [Indexed: 11/26/2022]
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11
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Kaysan G, Schork N, Herberger S, Guthausen G, Kind M. Contact-mediated nucleation in melt emulsions investigated by rheo-nuclear magnetic resonance. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:615-627. [PMID: 34700357 DOI: 10.1002/mrc.5228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/21/2021] [Accepted: 10/23/2021] [Indexed: 06/13/2023]
Abstract
Increasing the efficiency of disperse phase crystallization is of great interest for melt emulsion production as the fraction of solidified droplets determines product quality and stability. Nucleation events must appear within every single one of the μm-sized droplets for solidification. Therefore, primary crystallization requires high subcooling and is, thus, time and energy consuming. Contact-mediated nucleation is a mechanism for intensifying the crystallization process. It is defined as the successful nucleation of a subcooled liquid droplet induced by contact with an already crystallized droplet. We investigated contact-mediated nucleation under shear flow conditions up to shear rates of 457 s-1 for a quantitative assessment of this mechanism. Rheo-nuclear magnetic resonance was successfully used for the time-resolved determination of the solids fraction of the dispersed phase of melt emulsions upon contact-mediated nucleation events. The measurements were carried out in a dedicated Taylor-Couette cell. The efficiency of contact-mediated nucleation λsec decreased with increasing shear rate, whereas the effective second order kinetic constant kcoll,eff increased approximately linearly at small shear rates and showed a linear decrease for shear rates higher than about 200 s-1 . These findings are in accordance with coalescence theory. Thus, the nucleation rate is optimal at specific flow conditions. There are limitations for successful inoculation at a low shear rate because of rare contact events and at a high shear rate due to too short contact time.
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Affiliation(s)
- Gina Kaysan
- Institute for Thermal Process Engineering, KIT, Karlsruhe, Germany
| | - Nicolas Schork
- Institute for Mechanical Engineering and Mechanics, KIT, Karlsruhe, Germany
| | | | - Gisela Guthausen
- Institute for Mechanical Engineering and Mechanics, KIT, Karlsruhe, Germany
- Engler-Bunte Institute, Water Science and Technology, KIT, Karlsruhe, Germany
| | - Matthias Kind
- Institute for Thermal Process Engineering, KIT, Karlsruhe, Germany
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12
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Dudek M, Ruwoldt J, Øye G. Characterization and assessment of wax and wax inhibitors systems in microfluidic oil-in-water coalescence experiments. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2021.128186] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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Rutkowski GP, Azizov I, Unmann E, Dudek M, Grimes BA. Microfluidic droplet detection via region-based and single-pass convolutional neural networks with comparison to conventional image analysis methodologies. MACHINE LEARNING WITH APPLICATIONS 2022. [DOI: 10.1016/j.mlwa.2021.100222] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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14
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Porto Santos T, Cejas CM, Cunha RL. Microfluidics as a tool to assess and induce emulsion destabilization. SOFT MATTER 2022; 18:698-710. [PMID: 35037925 DOI: 10.1039/d1sm01588e] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Microfluidic technology enables judicious control of the process parameters on a small length scale, which in turn allows speeding up the destabilization of emulsion droplets interface in microfluidic devices. In this light, microfluidic channels can be used as an efficient tool to assess emulsion stability and to observe the behavior of the droplets immediately after their formation, enabling to determine whether or not they are prone to re-coalescence. Observation of the droplets after emulsifier adsorption also allows the investigation of emulsion stability over time. Both evaluations would contribute to determine emulsion stability aiming at specific applications in food and pharmaceutical industries. Furthermore, emulsion coalescence can also be performed under extremely controlled conditions within the microfluidic devices in order to explore emulsion droplets as micro-reactors (for regulated biological and chemical assays). Such microfluidic procedures can be performed either in confined environments or under dynamic flow conditions. Under confined environments, droplets are observed in fixed positions simulating different environmental conditions. On the other hand, with the scrutiny of emulsions under dynamic flow processes, it is possible to determine the behavior of the droplets when subjected to shear forces, comparable to those experienced in conventional emulsification techniques or even in pumping operations. Given the above, this paper reviews different microfluidic techniques (such as changing channel geometry or wettability) hitherto used to destabilize emulsions, mainly focusing on the specificities of each study, whether the droplets are destabilized in confined or dynamic flow processes. Thereby, by going deeper into this review, readers will be able to identify different strategies for emulsion destabilization (in order to understand stabilizing mechanisms or even to apply these droplets as micro-reactors), as this paper shows the particularities of the most recent studies and elucidates the current state-of-the-art of this microfluidic-related application.
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Affiliation(s)
- Tatiana Porto Santos
- Department of Food Engineering, Faculty of Food Engineering, University of Campinas, Rua Monteiro Lobato, 80-CEP 13083-862 Campinas, Brazil.
| | - Cesare M Cejas
- Microfluidics, MEMS, Nanostructures Laboratory, CNRS Chimie Biologie Innovation (CBI) UMR 8231, Institut Pierre Gilles de Gennes (IPGG), ESPCI Paris, PSL Research University, 6 rue Jean Calvin 75005, Paris, France.
| | - Rosiane Lopes Cunha
- Department of Food Engineering, Faculty of Food Engineering, University of Campinas, Rua Monteiro Lobato, 80-CEP 13083-862 Campinas, Brazil.
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15
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Ho TM, Razzaghi A, Ramachandran A, Mikkonen KS. Emulsion characterization via microfluidic devices: A review on interfacial tension and stability to coalescence. Adv Colloid Interface Sci 2022; 299:102541. [PMID: 34920366 DOI: 10.1016/j.cis.2021.102541] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 09/22/2021] [Accepted: 10/03/2021] [Indexed: 01/29/2023]
Abstract
Emulsions have gained significant importance in many industries including foods, pharmaceuticals, cosmetics, health care formulations, paints, polymer blends and oils. During emulsion generation, collisions can occur between newly-generated droplets, which may lead to coalescence between the droplets. The extent of coalescence is driven by the properties of the dispersed and continuous phases (e.g. density, viscosity, ion strength and pH), and system conditions (e.g. temperature, pressure or any external applied forces). In addition, the diffusion and adsorption behaviors of emulsifiers which govern the dynamic interfacial tension of the forming droplets, the surface potential, and the duration and frequency of the droplet collisions, contribute to the overall rate of coalescence. An understanding of these complex behaviors, particularly those of interfacial tension and droplet coalescence during emulsion generation, is critical for the design of an emulsion with desirable properties, and for the optimization of the processing conditions. However, in many cases, the time scales over which these phenomena occur are extremely short, typically a fraction of a second, which makes their accurate determination by conventional analytical methods extremely challenging. In the past few years, with advances in microfluidic technology, many attempts have demonstrated that microfluidic systems, characterized by micrometer-size channels, can be successfully employed to precisely characterize these properties of emulsions. In this review, current applications of microfluidic devices to determine the equilibrium and dynamic interfacial tension during droplet formation, and to investigate the coalescence stability of dispersed droplets applicable to the processing and storage of emulsions, are discussed.
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Deng B, Schroën K, de Ruiter J. Effects of dynamic adsorption on bubble formation and coalescence in partitioned-EDGE devices. J Colloid Interface Sci 2021; 602:316-324. [PMID: 34130178 DOI: 10.1016/j.jcis.2021.06.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 10/21/2022]
Abstract
HYPOTHESIS Dynamic adsorption effects can play a crucial role in bubble formation and stabilization. We hypothesize that microfluidic tools provide direct insights to these effects, and that the final bubble size depends on the intersection of time scales for bubble formation versus adsorption of proteins. EXPERIMENTS We use a microfluidic device to study Laplace pressure-driven formation of bubbles that are stabilized by whey proteins. Bubble behavior is studied as a function of the pressure difference imposed across the pores (Pd∗), and thus the bubble formation time (τ, ranging from μs to s), using highspeed recordings, quasi-static pressure arguments and a semi-empirical coalescence model. FINDINGS We observe two distinct bubble formation regimes, delimited by the pressure difference required to initiate bubble formation in pure water, Pd∗= 1400 mbar. When Pd∗<1400 mbar, protein adsorption is a requisite to lower the surface tension and initialize bubble formation. Individual bubbles (fixed d0~ 25 μm) are formed slowly with τ≫1 ms. When Pd∗ exceeds 1400 mbar, bubbles (fixed d0~ 16 μm) experience no adsorption lag and thus are formed at steeply increasing frequency, with τ < 1 ms. Interaction between these bubbles causes finite coalescence to a diameter dcoal that increases for lower τ. A minimum time of 0.4 ms is needed to immediately stabilize individual bubbles. Our study provides a promising microfluidic tool to study bubble formation and coalescence dynamics simultaneously.
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Affiliation(s)
- Boxin Deng
- Wageningen University, Food Process Engineering Group, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Karin Schroën
- Wageningen University, Food Process Engineering Group, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Jolet de Ruiter
- Wageningen University, Food Process Engineering Group, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands.
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17
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A microfluidic study of oil displacement in porous media at elevated temperature and pressure. Sci Rep 2021; 11:20349. [PMID: 34645911 PMCID: PMC8514519 DOI: 10.1038/s41598-021-99796-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/27/2021] [Indexed: 11/08/2022] Open
Abstract
Microfluidics methods offer possibilities for visual observations of oil recovery processes. Good control over test parameters also provides the opportunity to conduct tests that simulate representative reservoir conditions. This paper presents a setup and procedure development for microfluidic oil recovery tests at elevated temperature and pressure. Oil recovery factors and displacement patterns were determined in single- or two-step recovery tests using two crude oils, high salinity salt solutions and low salinity surfactant solutions. Neither the displacement pattern nor the recovery factor was significantly affected by the pressure range tested here. Increasing temperature affected the recovery factor significantly, but with opposite trends for the two tested crude oils. The difference was justified by changes in wettability alteration, due to variations in the amounts and structure of the acidic and basic oil fractions. Low salinity surfactant solutions enhanced the oil recovery for both oils.
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18
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Thin liquid films: Where hydrodynamics, capillarity, surface stresses and intermolecular forces meet. Curr Opin Colloid Interface Sci 2021. [DOI: 10.1016/j.cocis.2021.101441] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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19
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Aarøen O, Riccardi E, Sletmoen M. Exploring the effects of approach velocity on depletion force and coalescence in oil-in-water emulsions. RSC Adv 2021; 11:8730-8740. [PMID: 35423378 PMCID: PMC8695179 DOI: 10.1039/d1ra00661d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 02/18/2021] [Indexed: 11/21/2022] Open
Abstract
An emulsion is a thermodynamically unstable system consisting of at least two immiscible liquid phases, one of which is dispersed in the other in the form of droplets of varying size. Most studies on emulsions have focused on the behaviour of emulsion droplets with diameter from ∼50 μm and upwards. However, the properties of smaller droplets may be highly relevant in order to understand the behaviour of emulsions, including their performance in numerous applications within the fields of food, industry, and medical science. The relatively long life-time and small size of these droplets compared to other emulsion droplets, make them suited for optical trapping and micromanipulation technologies. Optical tweezers have previously shown potential in the study of stabilized emulsions. Here we employ optical tweezers to examine unstable oil-in-water emulsions to determine the effects of system parameters on depletion force and coalescence times.
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Affiliation(s)
- Ola Aarøen
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology Høgskoleringen 5 7491 Trondheim Norway
| | - Enrico Riccardi
- Department of Chemistry, Norwegian University of Science and Technology Høgskoleringen 5 7491 Trondheim Norway
- Department of Informatics, UiO Gaustadalléen 23B 0373 Oslo Norway
| | - Marit Sletmoen
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology Høgskoleringen 5 7491 Trondheim Norway
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Dudek M, Ullaland HS, Wehrle A, Øye G. Microfluidic testing of flocculants for produced water treatment: Comparison with other methodologies. WATER RESEARCH X 2020; 9:100073. [PMID: 33089131 PMCID: PMC7567950 DOI: 10.1016/j.wroa.2020.100073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 10/06/2020] [Accepted: 10/09/2020] [Indexed: 05/11/2023]
Abstract
Flocculants are often added during produced water treatment to improve the crude oil droplet growth and separation from the water phase. Prior to use in the field, their performance is tested in laboratory conditions, typically with jar tests that require quite large volumes of sample. In this paper we present a microfluidic method as an alternative to study the efficiency of flocculants on enhancing coalescence between oil droplets. Two crude oil emulsions and four flocculants at different concentrations were tested. The new method is also compared to the more traditional techniques. An anionic flocculant showed the biggest improvement in separation for almost all systems. What is more, marked differences were observed between methods with static (bottle and turbidity tests) and dynamic test conditions (light scattering and microfluidics), where stabilization and dispersion effects were observed for the latter. The microfluidic methodology, with added benefits such as visualization, lower sample volumes and shorter measurement times, yielded similar trends as compared to other techniques. Overall, it was shown that microfluidics is a viable alternative to the standard tests.
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Affiliation(s)
- Marcin Dudek
- Ugelstad Laboratory, Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Corresponding author. Sem Sælandsvei 4, Trondheim 7491, Norway.
| | - Hanne Skudal Ullaland
- Ugelstad Laboratory, Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Amandine Wehrle
- National Graduate School of Engineering (ENSICAEN), Caen, France
| | - Gisle Øye
- Ugelstad Laboratory, Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Corresponding author.
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21
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Bouhid de Aguiar I, Schroën K. Microfluidics Used as a Tool to Understand and Optimize Membrane Filtration Processes. MEMBRANES 2020; 10:E316. [PMID: 33138236 PMCID: PMC7692330 DOI: 10.3390/membranes10110316] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 12/13/2022]
Abstract
Membrane filtration processes are best known for their application in the water, oil, and gas sectors, but also in food production they play an eminent role. Filtration processes are known to suffer from a decrease in efficiency in time due to e.g., particle deposition, also known as fouling and pore blocking. Although these processes are not very well understood at a small scale, smart engineering approaches have been used to keep membrane processes running. Microfluidic devices have been increasingly applied to study membrane filtration processes and accommodate observation and understanding of the filtration process at different scales, from nanometer to millimeter and more. In combination with microscopes and high-speed imaging, microfluidic devices allow real time observation of filtration processes. In this review we will give a general introduction on microfluidic devices used to study membrane filtration behavior, followed by a discussion of how microfluidic devices can be used to understand current challenges. We will then discuss how increased knowledge on fundamental aspects of membrane filtration can help optimize existing processes, before wrapping up with an outlook on future prospects on the use of microfluidics within the field of membrane separation.
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Affiliation(s)
- Izabella Bouhid de Aguiar
- Membrane Science and Technology—Membrane Processes for Food, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands;
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22
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Chatzigiannakis E, Vermant J. Breakup of Thin Liquid Films: From Stochastic to Deterministic. PHYSICAL REVIEW LETTERS 2020; 125:158001. [PMID: 33095612 DOI: 10.1103/physrevlett.125.158001] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 09/08/2020] [Indexed: 06/11/2023]
Abstract
The thinning and rupture of thin liquid films is a ubiquitous process, controlling the lifetime of bubbles, antibubbles, and droplets. A better understanding of rupture is important for controlling and modeling the stability of multiphase products. Yet literature reports that film breakup can be either stochastic or deterministic. Here, we employ a modified thin film balance to vary the ratio of hydrodynamic to capillary stresses and its role on the dynamics of thin liquid films of polymer solutions with adequate viscosities. Varying the pressure drop across planar films allows us to control the ratio of the two competing timescales, i.e., a controlled hydrodynamic drainage time and a timescale related to fluctuations. The thickness fluctuations are visualized and quantified, and their characteristics are for the first time directly measured experimentally for varying strengths of the flow inside the film. We show how the criteria for rupture depend on the hydrodynamic conditions, changing from stochastic to deterministic as the hydrodynamic forces inside the film damp the fluctuations.
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Affiliation(s)
| | - Jan Vermant
- Department of Materials, ETH Zürich, Vladimir Prelog Weg 5, 8032 Zürich, Switzerland
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23
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Wang Y, Qian L, Chen Z, Zhou F. Coalescence of Binary Droplets in the Transformer Oil Based on Small Amounts of Polymer: Effects of Initial Droplet Diameter and Collision Parameter. Polymers (Basel) 2020; 12:polym12092054. [PMID: 32917051 PMCID: PMC7570392 DOI: 10.3390/polym12092054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/29/2020] [Accepted: 09/07/2020] [Indexed: 11/16/2022] Open
Abstract
In engineering applications, the coalescence of droplets in the oil phase dominates the efficiency of water-oil separation. To improve the efficiency of water-oil separation, many studies have been devoted to exploring the process of water droplets colliding in the oil phase. In this paper, the volume of fluid (VOF) method is employed to simulate the coalescence of water droplets in the transformer oil based on small amounts of polymer. The influences of the initial diameter and collision parameter of two equal droplets on droplet deformation and coalescence time are investigated. The time evolution curves of the dimensionless maximum deformation diameter of the droplets indicate that the larger the droplet diameter, the more obvious the deformation from central collisions. As the collision parameter increases, the contact area of the two droplets, as well as the kinetic energy that is converted into surface energy, decreases, resulting in an increase in droplet deformation. Furthermore, the effects of the initial droplet diameter and collision parameter on coalescence time are also investigated and discussed. The results reveal that as the initial droplet diameter and collision parameter increase, the droplet coalescence time increases.
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24
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Narayan S, Makhnenko I, Moravec DB, Hauser BG, Dallas AJ, Dutcher CS. Insights into the Microscale Coalescence Behavior of Surfactant-Stabilized Droplets Using a Microfluidic Hydrodynamic Trap. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:9827-9842. [PMID: 32693603 DOI: 10.1021/acs.langmuir.0c01414] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Coalescence of micrometer-scale droplets is impacted by several parameters, including droplet size, viscosities of the two phases, droplet velocity, angle of approach, as well as interfacial tension and surfactant coverage. The thinning dynamics of films between coalescing droplets can be particularly complex in the presence of surfactants, due to the generation of Marangoni stresses and reduced film mobility. Here, a microfluidic hydrodynamic "Stokes" trap is used to gently steer and trap surfactant-laden micrometer-sized droplets at the center of a cross-slot. Water droplets are formed upstream of the cross-slot using a microfluidic T-junction, in heavy and light mineral oils and stabilized using SPAN 80, an oil-soluble surfactant. Incoming droplets are made to coalesce with the trapped droplet, yielding measurements of the film drainage time. Film drainage times are measured as a function of continuous phase viscosity, incoming droplet speed, trapped droplet size, and surfactant concentrations above and below the critical micelle concentration (CMC). As expected, systems with higher surfactant concentrations and slower incoming droplet speed exhibit longer film drainage times. At low surfactant concentrations, the drainage time is longer for the more viscous heavy mineral oil in the continuous phase, whereas at high surfactant concentrations, the dependence on continuous phase viscosity vanishes. Perhaps more surprisingly, larger droplets and high confinement also result in longer film drainage times, potentially due to deformation of the droplet interfaces. The results are used here to determine critical conditions for coalescence, including both an upper and a lower critical capillary number. Moreover, it is shown that induced surfactant concentration gradient effects enable coalescence events after the droplets had originally flocculated, at surfactant concentrations above the CMC. The microfluidic hydrodynamic trap provides new insights into the role of surfactants in film drainage and opens avenues for controlled coalescence studies at micrometer length scales and millisecond time scales.
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Affiliation(s)
- Shweta Narayan
- Department of Mechanical Engineering, University of Minnesota-Twin Cities, Minneapolis, MN 55455, United States
| | - Iaroslav Makhnenko
- Department of Mechanical Engineering, University of Minnesota-Twin Cities, Minneapolis, MN 55455, United States
| | - Davis B Moravec
- Donaldson Company, Inc., Bloomington, MN 55431, United States
| | - Brad G Hauser
- Donaldson Company, Inc., Bloomington, MN 55431, United States
| | - Andrew J Dallas
- Donaldson Company, Inc., Bloomington, MN 55431, United States
| | - Cari S Dutcher
- Department of Mechanical Engineering, University of Minnesota-Twin Cities, Minneapolis, MN 55455, United States
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities, Minneapolis, MN 55455, United States
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25
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Zhang Z, Song J, Lin YJ, Wang X, Biswal SL. Comparing the Coalescence Rate of Water-in-Oil Emulsions Stabilized with Asphaltenes and Asphaltene-like Molecules. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:7894-7900. [PMID: 32597186 DOI: 10.1021/acs.langmuir.0c00966] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Asphaltenes are a significant contributor to flow assurance problems related to crude oil production. Because of their polydispersity, model molecules such as coronene and violanthrone-79 (VO-79) have been used as mimics to represent the physiochemical properties of asphaltenes. This work aims to evaluate the emulsion-stabilization characteristics of fractionated asphaltenes and these two model molecules. Such evaluation is expected to better characterize the stabilizing mechanisms of asphaltenes on water-in-oil emulsions. The coalescence process of water-in-oil emulsion droplets is visualized using a microfluidic flow-focusing geometry. The rate of coalescence events is used as the parameter to assess emulsion stability. Interfacial tension (IFT) and oil/brine zeta potential are measured to help explain the differences in the rates of coalescence. VO-79 is found to be better at stabilizing emulsions as compared to coronene. Although VO-79 and asphaltenes have similar interfacial tension and oil/brine zeta potential values, the rate of coalescence differs significantly. This highlights the difficulty in using model molecules to mimic the transport dynamics of asphaltenes.
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Affiliation(s)
- Zhuqing Zhang
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Jin Song
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Yu-Jiun Lin
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Xinglin Wang
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Sibani Lisa Biswal
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
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Dudek M, Vik EA, Aanesen SV, Øye G. Colloid chemistry and experimental techniques for understanding fundamental behaviour of produced water in oil and gas production. Adv Colloid Interface Sci 2020; 276:102105. [PMID: 31978641 DOI: 10.1016/j.cis.2020.102105] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 01/08/2020] [Accepted: 01/08/2020] [Indexed: 01/30/2023]
Abstract
Due to increasing volumes of produced water and environmental concerns related to its discharge, water treatment has become a major challenge during the production of crude oil and natural gas. With continuously stricter regulations for discharging produced water to sea, the operators are obliged to look for ways to improve the treatment processes or re-use the water in a beneficial way, for example as a pressure support during oil recovery (produced water re-injection). To improve the knowledge of the underlying phenomena governing separation processes, detailed information of the composition and interfacial properties of produced water is undoubtedly useful and could provide valuable input for better understanding and improving separation models. This review article summarizes knowledge gained about produced water composition and the most common treatment technologies, which are later used to describe the fundamental phenomena occurring during separation. These colloidal interactions, such as coalescence of oil droplets, bubble-droplet attachment or partitioning of components between oil and water, are of crucial importance for the performance of various technologies and are sometimes overlooked in physical considerations of produced water treatment. The last part of the review deals with the experimental methodologies that are available to study these phenomena, provide data for models and support development of more efficient separation processes.
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