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Li N, Pang Y, Sun Z, Sun X, Li W, Sun Y, Zhu L, Li B, Wang Z, Zeng H. Unraveling Partial Coalescence Between Droplet and Oil-Water Interface in Water-in-Oil Emulsions under a Direct-Current Electric Field via Molecular Dynamics Simulation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:5992-6003. [PMID: 38445586 DOI: 10.1021/acs.langmuir.3c04024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
When the electric field strength (E) surpasses a certain threshold, secondary droplets are generated during the coalescence between water droplets in oil and the oil-water interface (so-called the droplet-interface partial coalescence phenomenon), resulting in a lower efficiency of droplet electrocoalescence. This study employs molecular dynamics (MD) simulations to investigate the droplet-interface partial coalescence phenomenon under direct current (DC) electric fields. The results demonstrate that intermolecular interactions, particularly the formation of hydrogen bonds, play a crucial role in dipole-dipole coalescence. Droplet-interface partial coalescence is categorized into five regimes based on droplet morphology. During the contact and fusion of the droplet with the water layer, the dipole moment of the droplet exhibits alternating increases and decreases along the electric field direction. Electric field forces acting on sodium ions and the internal interactions within droplets promote the process of droplet-interface partial coalescence. High field strengths cause significant elongation of the droplet, leading to its fragmentation into multiple segments. The migration of hydrated ions has a dual impact on the droplet-interface partial coalescence, with both facilitative and suppressive effects. The time required for droplet-interface partial coalescence initially decreases and subsequently increases as the field strength increases, depending on the competitive relationship between the extent of droplet stretching and the electric field force. This work provides molecular insights into the droplet-interface coalescence mechanisms in water-in-oil emulsions under DC electric fields.
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Affiliation(s)
- Ning Li
- College of New Energy, China University of Petroleum (East China), Qingdao 266580, China
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G1H9, Canada
| | - Yunhui Pang
- College of New Energy, China University of Petroleum (East China), Qingdao 266580, China
| | - Zhiqian Sun
- College of New Energy, China University of Petroleum (East China), Qingdao 266580, China
| | - Xiaoyu Sun
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G1H9, Canada
| | - Wangqing Li
- College of New Energy, China University of Petroleum (East China), Qingdao 266580, China
| | - Yongxiang Sun
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G1H9, Canada
| | - Liyun Zhu
- College of New Energy, China University of Petroleum (East China), Qingdao 266580, China
| | - Bin Li
- School of Energy and Power Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Zhenbo Wang
- College of New Energy, China University of Petroleum (East China), Qingdao 266580, China
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G1H9, Canada
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Su X, Yang X, Yu Y, Gao F, Wang X. A simulation approach to predict electrostatic coalescence performance of water-in-oil emulsion using population balance model. SEP SCI TECHNOL 2022. [DOI: 10.1080/01496395.2022.2131577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Xin Su
- SINOPEC Dalian Research Institute of Petroleum and Petrochemicals Co, Ltd, 7th Research Division, Dalian, China
| | - Xiuna Yang
- SINOPEC Dalian Research Institute of Petroleum and Petrochemicals Co, Ltd, 7th Research Division, Dalian, China
| | - Ying Yu
- SINOPEC Dalian Research Institute of Petroleum and Petrochemicals Co, Ltd, 7th Research Division, Dalian, China
| | - Feng Gao
- SINOPEC Dalian Research Institute of Petroleum and Petrochemicals Co, Ltd, 7th Research Division, Dalian, China
| | - Xiaoxuan Wang
- Exploration and Development Research Institute of Huabei Oilfield Company, Renqiu, China
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Huang X, Luo X, Han Y, Li W, Lai Y, Teng L. Deformation and breakup of water droplets containing polymer under a
DC
electric field. AIChE J 2022. [DOI: 10.1002/aic.17786] [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]
Affiliation(s)
- Xin Huang
- College of Chemical Engineering Fuzhou University Fuzhou China
| | - Xiaoming Luo
- College of Pipeline and Civil Engineering, China University of Petroleum (East China) Qingdao China
| | - Yunrui Han
- Institute of Marine Science and Technology Shandong University Qingdao China
| | - Weidong Li
- College of Chemical Engineering Fuzhou University Fuzhou China
| | - Yuekun Lai
- College of Chemical Engineering Fuzhou University Fuzhou China
| | - Lin Teng
- College of Chemical Engineering Fuzhou University Fuzhou China
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Wang R, Fu M, Yang J, Zhong Y, Zhang R, Zhang Q, Liu Y, Zhou Y. Surface Charge Regulation of MIL-100(Fe) by Anion Exchange for Demulsifying the Cationic Surfactant-Stabilized O/W Emulsion. ACS APPLIED MATERIALS & INTERFACES 2021; 13:49964-49973. [PMID: 34652892 DOI: 10.1021/acsami.1c14602] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Demulsifying ionic surfactant-stabilized emulsions remains an emerging issue due to the stringent electrostatic barriers. In this work, a phosphate-mediated anion exchange strategy was proposed to fabricate a metal-organic framework, MIL-100(Fe), with adjustable surface charge for effective demulsification toward a cationic surfactant-stabilized emulsion. By adjusting the pH of the phosphate precursor solution, the surface charge of MIL-100(Fe) can be fine-tuned. At pH 3.0, the phosphate-exchanged MIL-100(Fe) with the zeta potential decreasing from 21.4 to 6.1 mV exhibited a significant enhancement of the demulsification efficiency (DE) from 35 to 91%. Further elevating the pH to 9.0 results in the zeta potential of the phosphate-exchanged MIL-100(Fe) to be reversed to -2.0 mV, and the DE can be optimized to 96% within 5 min. The demulsification mechanism was systematically explored based on the zeta potential, distribution of the surfactant, viscoelastic modulus evaluation, and morphological characterization of the emulsion in combination with monitoring of the dynamics process of demulsification. It was found that the phosphate-exchanged MIL-100(Fe) captured by the emulsion can lead to the release of the surfactant and heterogenization of the interfacial film, causing the elasticity of the emulsion to decrease and the irreversible deformation of emulsion droplets. Consequently, the destabilized emulsion could be subjected to the effective demulsification either by the fusion pathway mediated by the phosphate-exchanged MIL-100(Fe) or direct rupture. This work emphasized a facile and promising approach to deal with the cationic surfactant-emulsified oily wastewater and disclosed the fundamental demulsification process.
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Affiliation(s)
- Rui Wang
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan Province 610500, China
- Carbon Neutralization Research Institute, School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan Province 610500, China
| | - Miao Fu
- Carbon Neutralization Research Institute, School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan Province 610500, China
| | - Juncai Yang
- Carbon Neutralization Research Institute, School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan Province 610500, China
| | - Yunqian Zhong
- Carbon Neutralization Research Institute, School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan Province 610500, China
| | - Ruiyang Zhang
- Carbon Neutralization Research Institute, School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan Province 610500, China
| | - Qian Zhang
- Carbon Neutralization Research Institute, School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan Province 610500, China
| | - Yucheng Liu
- College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan Province 610500, China
| | - Ying Zhou
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan Province 610500, China
- Carbon Neutralization Research Institute, School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan Province 610500, China
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Nie C, Han G, Ni J, Guan S, Du H, Zhang Y, Wang H. Stability Dynamic Characteristic of Oil-in-Water Emulsion from Alkali-Surfactant-Polymer Flooding. ACS OMEGA 2021; 6:19058-19066. [PMID: 34337244 PMCID: PMC8320156 DOI: 10.1021/acsomega.1c02367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/09/2021] [Indexed: 05/04/2023]
Abstract
The relationship model between the droplet lifetime and interface properties is established to characterize the stability of oil droplets, and then, the influence of the alkali-surfactant-polymer (ASP) concentration on the lifetime is analyzed by theoretical calculations. The stability dynamic characteristics of oil-in-water (O/W) emulsions from ASP flooding were evaluated using the emulsion stability model (Civan model) based on two-phase separation. The effect of ASP on dynamic characteristics of the emulsion was explored by analyzing film strength qualitatively and measuring interfacial tension and ζ potential. The results showed that the Civan model was suitable to evaluate the stability of the O/W emulsion and to obtain the corresponding dynamic characteristics. The O/W emulsions became more stable with the increasing alkali concentration first at a low alkali concentration (c NaOH < 200 mg/L) and then became less stable with the increasing alkali concentration at a high alkali concentration (c NaOH > 200 mg/L). The stabilities of O/W emulsions were improved with the increasing concentrations of the surfactant and polymer. The mechanism of stabilization of the O/W emulsion by ASP is as follows. The surface-active substances formed by the reaction of alkali and acidic substances in the oil phase, together with surfactants, adsorb at the oil-water interface, reducing the interfacial tension and increasing the strength of the oil-water interface film. The polymer only increases the strength of the interface film by increasing the viscoelasticity of the oil-water interface film.
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Qi C, Li Y, Liu Z, Kong T. Electrohydrodynamics of droplets and jets in multiphase microsystems. SOFT MATTER 2020; 16:8526-8546. [PMID: 32945331 DOI: 10.1039/d0sm01357a] [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
Electrohydrodynamics is among the most promising techniques for manipulating liquids in microsystems. The electric stress actuates, generates, and coalesces droplets of small sizes; it also accelerates, focuses, and controls the motion of fine jets. In this review, the current understanding of dynamic regimes of electrically driven drops and jets in multiphase microsystems is summarized. The experimental description and underlying mechanism of force interplay and instabilities are discussed. Conditions for controlled transitions among different regimes are also provided. Emerging new phenomena either due to special interfacial properties or geometric confinement are emphasized, and simple scaling arguments proposed in the literature are introduced. The review provides useful perspectives for investigations involving electrically driven droplets and jets.
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Affiliation(s)
- Cheng Qi
- College of Mechatronics and Control Engineering, Shenzhen University, Shenzhen 518000, Guangdong, China
| | - Yao Li
- College of Mechatronics and Control Engineering, Shenzhen University, Shenzhen 518000, Guangdong, China
| | - Zhou Liu
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518000, Guangdong, China.
| | - Tiantian Kong
- Department of Biomedical Engineering, School of Medicine, Shenzhen University, Shenzhen 518000, Guangdong, China.
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