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Chen Z, Wang X, Zhang J, Zhang W, Duan M, Xiong Y, Fang S. Study on the structure-activity relationship of cationic polyacrylates for the treatment of oilfield produced water. RSC Adv 2024; 14:8124-8134. [PMID: 38464688 PMCID: PMC10921276 DOI: 10.1039/d4ra00188e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 03/05/2024] [Indexed: 03/12/2024] Open
Abstract
Cationic polyacrylates exhibit both reverse demulsification and flotation performance, which can avoid incompatibility between the reverse demulsifier and flotation agent during treatment of produced water from offshore oilfields. In our previous work, the effect of the structure of the cationic unit on the reverse demulsification and flotation performance of cationic polyacrylates was studied. However, the structure-activity relationship of cationic polyacrylates has not been systematically studied. In this study, the relationships between the structure (acrylate type, tertiary amine type, mass ratio of acrylate to tertiary amine, and degree of cationicity), interfacial properties (surface tension, interfacial tension, zeta potential, interfacial elastic modulus, interaction force between oil droplets, and film drainage time of an oil-covered bubble), and reverse demulsification and flotation performance of cationic polyacrylates were investigated. A reduction in the elastic modulus of the oil-water interface was the key factor for good reverse demulsification performance, whereas a decrease in the film drainage time of an oil-covered bubble was the key factor for good flotation performance. Ethyl acrylate (EA) was superior to methyl acrylate (MA), and dimethylaminopropyl methacrylamide (DPM) was superior to dimethylaminoethyl methacrylate (DEM). Increases in the mass ratio of ethyl acrylate to dimethylaminopropyl methacrylamide and the degree of cationicity were beneficial for reducing the elastic modulus of the oil-water interface and the film drainage time of an oil-covered bubble. This is the first time that the structure-property-performance relationship of cationic polyacrylates has been systematically studied. A cationic polyacrylate that exhibited both good reverse demulsification performance and good flotation performance is recommended.
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Affiliation(s)
- Zhiping Chen
- School of Chemistry and Chemical Engineering, Southwest Petroleum University 8 Xindu Avenue, Xindu District Chengdu Sichuan 610500 China +86-2883037346 +86-2883037346
| | - Xiujun Wang
- State Key Laboratory of Offshore Oil Exploitation Beijing China
- CNOOC Research Institute Company, Ltd. Beijing China
| | - Jian Zhang
- State Key Laboratory of Offshore Oil Exploitation Beijing China
- CNOOC Research Institute Company, Ltd. Beijing China
| | - Wenju Zhang
- School of Chemistry and Chemical Engineering, Southwest Petroleum University 8 Xindu Avenue, Xindu District Chengdu Sichuan 610500 China +86-2883037346 +86-2883037346
| | - Ming Duan
- School of Chemistry and Chemical Engineering, Southwest Petroleum University 8 Xindu Avenue, Xindu District Chengdu Sichuan 610500 China +86-2883037346 +86-2883037346
| | - Yan Xiong
- School of Chemistry and Chemical Engineering, Southwest Petroleum University 8 Xindu Avenue, Xindu District Chengdu Sichuan 610500 China +86-2883037346 +86-2883037346
| | - Shenwen Fang
- School of Chemistry and Chemical Engineering, Southwest Petroleum University 8 Xindu Avenue, Xindu District Chengdu Sichuan 610500 China +86-2883037346 +86-2883037346
- Industrial Hazardous Waste Disposal and Resource Utilization Research Institute, Southwest Petroleum University Chengdu Sichuan China
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Khalesi Moghaddam R, Mhatre S, Yarranton HW, Natale G. Optical Tweezers-Based Measurements of Colloidal Forces between Asphaltene Thin Films: Effect of Ultrasonication. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:17009-17020. [PMID: 38000781 DOI: 10.1021/acs.langmuir.3c01183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2023]
Abstract
Oil production and processing often involve the treatment of water-in-oil emulsions stabilized by asphaltenes. The asphaltenes adsorb irreversibly at the water-oil interface and, by self-association at the interface, form a viscoelastic film that stabilizes the emulsions mechanically and sterically. Hydrophobic forces associated with these films may also contribute to the emulsion stability. A key step in treating these emulsions is to weaken the asphaltene film at the interface, and one way to do so is with ultrasonic treatment. The effect of ultrasonic waves on the interactions between asphaltene films was investigated at a silica-water interface using optical tweezers. Silica microparticles were aged in asphaltene solutions to form asphaltene coatings on their surfaces. The particles were dispersed in water, and interparticle force measurements were performed with optical tweezers to capture the steric force and hydrophobic force contributions. The asphaltene coating thickness and hydrophobic coefficient (a factor resembling the strength of the hydrophobic interaction) were obtained from fitting these forces. The effect of ultrasonication on the thickness of the asphaltene films on the surfaces of the particles was investigated. No change in the hydrophobic coefficient was observed upon changing the interfacial asphaltene concentration. The asphaltene film thickness increased with the concentration of the asphaltene solution and aging time. After treatment of the dispersion with ultrasonic waves for different durations (between 5 and 40 min), a significant reduction in the coating thickness was observed. This reduction was confirmed by thermogravimetric analysis (TGA) measurements. It is hypothesized that cavitation at the interface removed part of the surface layer of asphaltenes from the coated particles. Based on these findings, we proved that a low-power ultrasound field can effectively break asphaltene-stabilized water-in-oil emulsions.
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Affiliation(s)
- R Khalesi Moghaddam
- Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada
| | - S Mhatre
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, BC V6T 1Z3, Canada
| | - H W Yarranton
- Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada
| | - G Natale
- Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada
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Yang N, Zhang Y, Su C, Zhu C, Jia J, Nishinari K. The effect of sodium alginate on the nanomechanical properties and interaction between oil body droplets studied using atomic force microscopy. Food Hydrocoll 2023. [DOI: 10.1016/j.foodhyd.2023.108587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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Yan J, Yang Z, Qiao X, Kong Z, Dai L, Wu J, Xu X, McClements DJ. Interfacial characteristics and in vitro digestion of emulsion coated by single or mixed natural emulsifiers: lecithin and/or rice glutelin hydrolysates. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2022; 102:2990-2999. [PMID: 34773407 DOI: 10.1002/jsfa.11639] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 10/12/2021] [Accepted: 11/13/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND The interfacial characteristics and in vitro digestion of emulsion were related to emulsifier type. The mean droplet diameter, ζ-potential, microstructure, interfacial tension, Quartz crystal microbalance with dissipation (QCM-D) and in vitro gastrointestinal fate of emulsions stabilized by soybean lecithin, hydrolyzed rice glutelin (HRG) and their mixture were researched. RESULTS The value of interfacial tension was much more dramatically declined for the sample containing 20 g kg-1 of HRG. For QCM-D, a rigid layer was formed for all the samples after rinsing. The layer thickness was 0.87 ± 0.20, 2.11 ± 0.31 and 2.63 ± 0.22 nm, and adsorbed mass was 87.17 ± 10.31, 210.56 ± 20.12 and 263.09 ± 23.23 ng cm-2 , for HRG, lecithin and HRG/lecithin, respectively, indicating both HRG and lecithin were adsorbed at the oil-water interface. Structural rearrangements at the interface occurred for HRG/lecithin. The kinetics and final amount of lipid digestion depended on emulsifier type: lecithin > HRG/lecithin > HRG. These differences in digestion rate were primarily due to differences in the aggregation state of the emulsifiers. CONCLUSION The incorporation of lecithin into HRG emulsions had better interfacial properties comparing with HRG emulsion and facilitated lipid digestibility. These results provide important information for the rational design of plant-based functional food. © 2021 Society of Chemical Industry.
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Affiliation(s)
- Jiakai Yan
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Zhenyu Yang
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Xin Qiao
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Zhihao Kong
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Lei Dai
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Jianyong Wu
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China
| | - Xingfeng Xu
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
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Wang Y, Fang S, Wang X, Wang Y, Xiong Y, Duan M. Synthesis of a novel reverse demulsifier with the characteristics of polyacrylate and polycation and its demulsification performance. J Appl Polym Sci 2021. [DOI: 10.1002/app.51200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Yifan Wang
- College of Chemistry and Chemical Engineering Southwest Petroleum University Chengdu China
| | - Shenwen Fang
- College of Chemistry and Chemical Engineering Southwest Petroleum University Chengdu China
| | - Xiujun Wang
- Beijing Research Center China National Offshore Oil Corporation Beijing China
- EOR Research Center State Key Laboratory of Offshore Oilfield Exploitation Beijing China
| | - Yongjun Wang
- Oilfield Chemicals R&D Center CNOOC(Tianjin) Oilfield Chemical Co., Ltd Tianjin China
| | - Yan Xiong
- College of Chemistry and Chemical Engineering Southwest Petroleum University Chengdu China
| | - Ming Duan
- College of Chemistry and Chemical Engineering Southwest Petroleum University Chengdu China
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Nakauchi H, Maeda M, Kanayama N. Terminal Sequence-Specific Interparticle Attraction between DNA Duplex-Carrying Polystyrene Microparticles in Aqueous Salt Solution Assessed by Optical Tweezers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:5573-5581. [PMID: 33871256 DOI: 10.1021/acs.langmuir.1c00349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The dispersion behavior of DNA duplex-carrying colloidal particles in aqueous high-salt solutions shows extraordinary selectivity against the duplex terminal sequence. We investigated the interparticle force between DNA duplex-carrying polystyrene (dsDNA-PS) microparticles in aqueous salt solutions and examined their behavior in relation to the duplex terminal sequences. Force-distance (F-D) curves for a pair of dsDNA-PS particles were recorded with a dual-beam optical tweezers system with the two optically trapped particles closely approaching each other. Interestingly, only 3-5% of the oligo-DNA strands on the dsDNA-PS particles formed a duplex with complementary DNAs, and the F-D curves showed a distinct specificity to the duplex terminal sequences in the interparticle force at a high-NaCl concentration; a clear attraction peak was observed in F-D curves only when the duplex terminal was a complementary base pair. The attractive strength reached 2.6 ± 0.5 pN at 500 mM NaCl and 4.3 ± 1.0 pN at 750 mM NaCl. By sharp contrast, no significant attraction occurred for the particles with mismatched duplex terminals even at 750 mM NaCl. Similar duplex terminal-specificity in the interparticle force was also confirmed for dsDNA-PS particles in divalent MgCl2 solutions. Considering that the duplex terminal sequences on the dsDNA-PS particles showed only a negligible difference in their surface charges under identical salt conditions, we concluded that the interparticle attraction observed only for the dsDNA-PS particles with complementary duplex terminals is attributable to the salt-facilitated stacking interaction between the paired terminal nucleobases (i.e., blunt-end stacking) on the dsDNA-PS surfaces. Our results thus demonstrate the occurrence of a duplex terminal-specific interparticle force between dsDNA-PS particles under high-salt conditions.
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Affiliation(s)
- Hiroya Nakauchi
- Department of Biomedical Engineering, Graduate School of Medicine, Science and Technology, Shinshu University, 4-17-1 Wakasato, Nagano-shi, Nagano 380-8553, Japan
| | - Mizuo Maeda
- Department of Biomedical Engineering, Graduate School of Medicine, Science and Technology, Shinshu University, 4-17-1 Wakasato, Nagano-shi, Nagano 380-8553, Japan
- Bioengineering Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Naoki Kanayama
- Department of Biomedical Engineering, Graduate School of Medicine, Science and Technology, Shinshu University, 4-17-1 Wakasato, Nagano-shi, Nagano 380-8553, Japan
- Bioengineering Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Institute of Biomedical Science, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan
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Chen A, Liu X, Wu Y, Luo G, Xu JH. Interactions between CO 2-Responsive Switchable Emulsion Droplets Determined by Using Optical Tweezers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:4600-4606. [PMID: 32299211 DOI: 10.1021/acs.langmuir.0c00203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
CO2-responsive switchable emulsions have been of great interest in some industrial processes where the stability of the emulsion is only required temporarily, such as oil transport, drug delivery, and fossil fuel production. The good understanding of the stability and instability mechanism is vital to the switchable behavior between emulsification and demulsification. Herein, a novel approach was developed to determine the interactions between two switchable emulsion droplets directly by a dual-laser optical tweezers instrument. The repulsive force between a couple of tetradecane droplets occurs to increase progressively with the increasing concentration of switchable surfactant in solutions. However, the repulsive force appears to decrease progressively in turn when the switchable surfactant concentration is far higher than the critical micelle concentration (CMC). Moreover, the depletion effect starts to emerge in the higher surfactant concentration which is attributed to the switchable surfactant micelles generated in solutions. In addition, according to the measurements of interaction forces, a mechanism of the switchable behavior is well proposed, which is established by the principle of self-assembly/detachment of the switchable surfactant, resulting in the weakening and re-enhancing of the electrostatic double-layer (EDL) repulsive forces between tetradecane droplets, upon selective introduction and removal of CO2. Based on this work, a novel perspective was provided to study the switchable emulsion, which can contribute instructive messages for the understanding of stability and instability mechanisms of switchable emulsions.
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Affiliation(s)
- An Chen
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Xueyan Liu
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Yuxin Wu
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Guangsheng Luo
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Jian-Hong Xu
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
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Chen A, Wang F, Zhou Y, Xu JH. In Situ Measurements of Interactions between Switchable Surface-Active Colloid Particles Using Optical Tweezers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:4664-4670. [PMID: 32279500 DOI: 10.1021/acs.langmuir.0c00398] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Switchable surface-active colloid particles are critical to the preparation of switchable Pickering emulsions, which are widely involved in multitudinous fundamental and practical fields, such as biomedical, food products, and spinning cosmetics. The stability of switchable surface-active particles relies on the full understanding of interaction forces between individual colloid particles quantitatively. In this work, a dual-laser optical tweezers instrument was applied to measure the interaction forces between silica particles coated with a common cationic surfactant (cetyltrimethylammonium bromide, CTAB) in water, and all of the measured forces can be well fitted with the theoretical model derived from the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. It was revealed that the minimum surface distance to engender the interaction forces between silica particles was closer progressively with the increase of CTAB concentrations, suggesting that the introduction of CTAB molecules in the solution thinned the electric double layer. In addition, the minimum surface distance between surface-inactive silica particles further decreased compared to surface-active states, although the ζ-potential has returned to the initial value of bare silica in pure water when the molecular ratio of 1:1 anionic surfactant (sodium dodecyl sulfate, SDS) was added into the solution to switch the surface-active silica particles to surface-inactive states. Our results provide a considerate methodology for quantifying the interaction forces and investigating the switchable behaviors of CTAB molecules from the adsorption to desorption at the particle-water interfaces, which provide vital foresights into the stabilization mechanism of switchable surface-active colloid particles and the further development of switchable Pickering emulsions.
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Affiliation(s)
- An Chen
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Fajun Wang
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Yiwei Zhou
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Jian-Hong Xu
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
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Liu S, Hu Y, Xia J, Fang S, Duan M. In Situ Measurement of Depletion Caused by SDBS Micelles on the Surface of Silica Particles Using Optical Tweezers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:13536-13542. [PMID: 31574218 DOI: 10.1021/acs.langmuir.9b02041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Dual-trap optical tweezers have been used to directly measure the interaction forces between two silica particles upon controlling the concentration of the ionic surfactant sodium dodecylbenzenesulfonate (SDBS). By capturing two silica particles in one spot optical trap and one linear optical trap and controlling the linear trap to bring one particle to approach another sufficiently closer, the interaction forces between these two particles can be measured as the separation distance changes. Results showed that with increasing concentrations of SDBS, the interaction force between the two silica particles emerges at closer surface distance between two silica particles. Only repulsive force exists between silica particles below the critical micelle concentration (cmc) of SDBS and it could be well-fitted using the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. However, the depletion attraction force appears above the cmc of SDBS which is induced by the generation of SDBS micelles. By in situ measurement of the interaction force between two silica particles in the presence of different concentrations of SDBS, the depletion force can be quantitatively calculated.
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Affiliation(s)
- Shuai Liu
- Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, College of Chemistry and Chemical Engineering , Southwest Petroleum University , Chengdu , Sichuan 610500 , P. R. China
| | - Yue Hu
- Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, College of Chemistry and Chemical Engineering , Southwest Petroleum University , Chengdu , Sichuan 610500 , P. R. China
| | - Jing Xia
- School of Engineering and Applied Sciences , Harvard University , Cambridge , Massachusetts 02138 , United States
| | - Shenwen Fang
- Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, College of Chemistry and Chemical Engineering , Southwest Petroleum University , Chengdu , Sichuan 610500 , P. R. China
| | - Ming Duan
- Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, College of Chemistry and Chemical Engineering , Southwest Petroleum University , Chengdu , Sichuan 610500 , P. R. China
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Chen A, Li SW, Jing D, Xu JH. Interactions between colliding oil drops coated with non-ionic surfactant determined using optical tweezers. Chem Eng Sci 2019. [DOI: 10.1016/j.ces.2018.09.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Zhang L, Xie L, Cui X, Chen J, Zeng H. Intermolecular and surface forces at solid/oil/water/gas interfaces in petroleum production. J Colloid Interface Sci 2018; 537:505-519. [PMID: 30469119 DOI: 10.1016/j.jcis.2018.11.052] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/12/2018] [Accepted: 11/12/2018] [Indexed: 11/25/2022]
Abstract
Many challenging issues are encountered along the petroleum production such as the wettability alteration of reservoir solids due to deposition of petroleum materials, stabilization/destabilization of water-in-oil and oil-in-water emulsions and treatment of tailings water. All these problems are essentially driven by the fundamental intermolecular and surface forces among the different components (i.e., water, oil, solid and gas) in the surrounding complex fluid media, and comprehensive understanding of the interactions among these components will pave the way to the development of advanced materials and technologies for improved petroleum production processes. In this work, we have reviewed the quantitative force measurement methods in different petroleum systems by using nanomechanical techniques including surface forces apparatus (SFA) and atomic force microscope (AFM). Interaction forces between petroleum components (e.g., asphaltenes) and mineral solids in both organic solvents and aqueous solutions are reviewed and correlated to the wettability change of the reservoir solids. The recent key progress in quantifying the surface forces of water-in-oil and oil-in-water emulsion drops using AFM drop probe techniques are discussed. The interaction forces of polymer flocculants and colloidal particles are correlated to the performance of tailings water treatment. The current knowledge gap and future perspectives are also presented.
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Affiliation(s)
- Ling Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Lei Xie
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Xinwei Cui
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Jingsi Chen
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada.
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Bizmark N, Ioannidis MA. Nanoparticle-stabilised emulsions: droplet armouring vs. droplet bridging. SOFT MATTER 2018; 14:6404-6408. [PMID: 30035287 DOI: 10.1039/c8sm00938d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We speculate that the ability of small nanoparticles to stabilise emulsions via droplet bridging is controlled by the balance between an energy increase, due to the interaction between two oil-water interfaces in close proximity through surface forces, and an energy decrease due to the adsorption of a bridging particle on two oil-water interfaces. For nanoparticles of diameter greater than about 10 nm, tuning this interaction may render bridging possible, whereas nanoparticles smaller than 10 nm may stabilise emulsions only via the formation of dense layers of adsorbed particles on droplets. Both predictions are experimentally testable.
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Affiliation(s)
- Navid Bizmark
- Department of Chemical Engineering, University of Waterloo, 200 University Ave. West., Waterloo, ON N2L 3G1, Canada.
| | - Marios A Ioannidis
- Department of Chemical Engineering, University of Waterloo, 200 University Ave. West., Waterloo, ON N2L 3G1, Canada.
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Chen A, Li SW, Sang FN, Zeng HB, Xu JH. Interactions between micro-scale oil droplets in aqueous surfactant solution determined using optical tweezers. J Colloid Interface Sci 2018; 532:128-135. [PMID: 30077826 DOI: 10.1016/j.jcis.2018.07.116] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 07/26/2018] [Accepted: 07/27/2018] [Indexed: 01/09/2023]
Abstract
HYPOTHESIS The stability of the emulsions is crucial, which relies on a well-developed understanding of dynamic interaction forces between single dispersed droplets. In the previous studies, many interests focus on the oil droplets of size range of 20-200 µm. However, emulsion droplets with diameter below 10 µm are rarely mentioned, which is the size scale of real emulsion droplets in various applications, such as toners, spacers for liquid crystal displays, and materials in biomedical and biochemical analysis. The micro-scale droplets have many differences on the deformation, internal pressure and hydrodynamic effects. It is necessary to understand the interaction mechanisms between two real size scales of oil droplets for guiding practical production and application. EXPERIMENTS In this work, tetradecane was chosen as the model oil phase in all experiments. The interaction forces of two tetradecane droplets with the diameter of 5.0 µm in water in the presence of surfactant and salt solution were directly measured using optical tweezers. The force-distance curves were established, and the zeta potential of tetradecane droplets was studied using Zetasizer Nano ZSP. FINDINGS The absolute value of zeta potential of tetradecane droplets was found to decrease with the increase of salt concentration and increase with the increase of surfactant concentration. The repulsive force between two tetradecane droplets was found to decrease with the increase of salt concentration because the electrostatic double-layer force was suppressed gradually with the increase of salt concentration. The "hydrodynamic suction" effect during the process of retraction becomes more pronounced due to the corresponding increase in the hydrodynamic force with the increase of the approaching velocity between the tetradecane droplets. Furthermore, we found the existing model for the measurement of large droplets by atomic force microscope (AFM) is invalid for the measurement of micro-scale droplets by optical tweezers. The deformation of colliding micro-scale droplets can be safely ignored, which is quite different from the large droplets. Our results provide a useful method to study the interaction forces between micro-scale emulsion droplets with pN force resolution, and gives a deep insight of the stabilization mechanism of real size scale of O/W emulsions. These findings have significant implications on the stability of emulsions in many food, cosmetics, medicine, and advanced materials.
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Affiliation(s)
- An Chen
- The State Key Lab of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, PR China
| | - Shao-Wei Li
- Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, PR China.
| | - Fu-Ning Sang
- The State Key Lab of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, PR China
| | - Hong-Bo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Jian-Hong Xu
- The State Key Lab of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, PR China.
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